[MOD] Self Powered USB OTG on the HP Touchpad! (v2 Full Size) 11-30-12

[MOD] Self Powered USB OTG on the HP Touchpad! (v2 Full Size) 11-30-12 - TouchPad General

First:
Major Credit to SDX's FTEN for being first with his very original idea and micro Usb version of this hardware mod. If it weren't for him, I would not have dared to do this.
See his original thread: Self Powered USB Host on the HP Touchpad! and at RootzWiki
SDX Version of this thread
Rootzwiki Version of this thread
DISCLAIMER: I'm not a dev, nor do I play one on t.v. Use the information and links at your own risk. Read and understand what you're doing FIRST is the best bet. I take no credit for the original idea, just ran a bit farther out on the branch before it broke.
Afterwards be sure to check out:
[Tips and Tricks] OTG (USB Host Support) - Requires kernel support
and
My 2 Port 2 Amp OTG Charger & Mod post further down.
This is a difficult modification that requires you to completely disassemble Touchpad (correct tools a plus), cut and dremel out excess material from the back cover (risk of permanent damage) and display frame. You also need to have some soldering equipment plus skill with very small circuit boards/traces (if you want more than a full size power port) and loads of patience (this took several hours over 4-6 separate days).
Still interested? Have a look:
Parts:
- USB-A Female Connector from a USB Extension cable (and it's spare wire)
(or optional microUSB breakout as FTEN used in his original version)
- Small, thin, SPDT switch (single pole double throw) from a Dollar Store toy, ie "DollarTree"
- VPack PRT-08290 (5v Regulator) and it's PDF Reference file
- micro USB (M) connector from a cable or OTG Adapter (if you can't get the Enable switch landed you'll need this cut up into a plug with the ID pin shorted)
( or maybe AppleCable's Powered OTG Cable )
Tools:
- Spudger Tool set (or similar for cracking open the TP)
- Variable Speed Dremel with "Rotary File" bit
- Decent Soldering Iron (ie: Weller WES51) with small conical tip, and small electrical solder (LeadFree compatible recommended)
- Hobby knife Set (ie X-Acto with various blades and handles)
- Hot Glue Gun and sticks
Basic Disassembly/Reassembly: iFixit's HP Touchpad Battery Removal Guide
(You should be confident with the above. Be prepared to break a few of the 7 clips; superglue helps).
The Finished Product:
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Part 0 - Parts, Planning, & Schematics:
My Original sketch of the wiring schematic for the mod
The 3.7v to 5vdc Step-Up Regulator board
My wife's Simon Toy supplied the OTG Enable Switch (she wasn't thrilled)
Here's another option for the switch from my local "DollarTree" store
Here's the Full Size USB-A Extension Cable before and after modifiying
Lesson Learned: Go ahead and strip the Potting Material off the USB-A (F) connector to expose the 4 solder points and remove the wires (or at least the 2 DATA lines). I think you will have better success if you "land" the Data wires and OTG Enable Switch wire to the TP's USB Controller Board first and then connect the leads to the USB-A Connector and Enable Switch since those solder points are more durable.
** Make sure that the cable wiring is "Copper Colored" not silver, etc. The copper wire will solder more easily without damage to the USB Controller Board later on **

Part 1 Pictures (MB Power Leads and Routing):

Part 1 pictures (Sim Slot Modification & Test Fitting):
When it's all mounted up (Later) the connector will stick out the back like this:

Part 1 Pictures (Regulator/Connector Placement and Wiring)
Soldering the Battery leads to the Regulator input (take time to get the length & routing correct)
* See Previous note about soldering Data and OTG Switch wire to USB Controller Board First *
Here the 5vdc to the USB connector is soldered to the Regulator Output & a DC Rtn from the regulator is soldered to the switch's "common".

Part 2 Pictures (Sim Slot/Display frame notching)

Part 3 Pictures (USB Controller Board info)
Part 3 Pictures (USB Controller Board info)
Note: You can skip this step if you just want a full size USB-A power port and don't care about it having working "data" communication and OTG Enable Switch (I screwed up the enable switch solder pad).
Please read the notes in the pictures for this section, they will help avoid my mistakes.

Part 4 Pictures (finished)
Updated: 12-3-12

Additional Reference Info
Here'a an OTG Cable reference schematic that I made to help people make their own OTG cables and OTG shorting plugs. It works as a good reference to figure out how a purchased cable is wired up (some are different).
And here's a picture of the micro-USB breakout board (4pins only) from Sparkfun.com that Ften used in his original mod mentioned at the top of the OP. If you prefer, you can squeeze this into the sim slot without dremeling the back cover to a "paper thinness" and hook up your data and pwr to it, but you will have to make or purchase a male microUSB to USB-A adapter (an OTG one would work since there isn't an ID pin hooked up). I avoided this option because I don't want someone hooking it up to a USB wall charger by accident and possibly killing the regulator

2 Port 2Amp USB OTG Charger & Mod
Here's an update...
My CrazyOnDigital 2 port charger doesn't have the data pins shorted (D+ and D-) like the stock HTC unit. This causes any "Android" phone to charge at the lower 500ma Max "Charging USB" rate vs "AC Charging" (explains my slow charging when travelling), but a bonus is that it allows me to pass data b/w the 2 ports like a simple hub.
- If the D+ and D- pins are shorted when an OTG USB cable is plugged in, the phone/device will go into "AC Charging" mode, but not allow OTG devices to work, but if the phone is still connected and the data pins opened back up, you retain "AC Charging" mode and have USB OTG functions.
(I'm thinking that a simple on/off switch installed across the data pins of my charger will give me a dual mode charger).
AC CHARGING / USB CHARGING (Data Pass Through) MOD 12-1-12
- I got tired of having a 2 port 2 Amp charger that only allowed 500ma "USB Charging" with Android & OTG. See pix:

Since breaking my power button and not knowing where to find a replacement part, I am very interested in what you are doing here.
I was considering finding a way to install an SDHC card in the same spot you've done your USB port. Do you imagine that there would be any additional complications?
I'd also like to add a power switch via the battery.
Sent from my SAMSUNG-SGH-T989 using xda premium

-SGA- said:
Since breaking my power button and not knowing where to find a replacement part, I am very interested in what you are doing here.
I was considering finding a way to install an SDHC card in the same spot you've done your USB port. Do you imagine that there would be any additional complications?
I'd also like to add a power switch via the battery.
Sent from my SAMSUNG-SGH-T989 using xda premium
Click to expand...
Click to collapse
In case you not aware there is an app called Button Saviour that can mimic all your hardware buttons including power.
Edit which I have just realised is of no help whatsoever if your Tablet is off . Best of luck.

-SGA- said:
Since breaking my power button and not knowing where to find a replacement part, I am very interested in what you are doing here.
I was considering finding a way to install an SDHC card in the same spot you've done your USB port. Do you imagine that there would be any additional complications?
I'd also like to add a power switch via the battery.
Click to expand...
Click to collapse
My suggestion for the power switch would be to get another TP off Ebay to rob for the switch (probably the only way I will get another USB board to finish my OTG mod 100%). I saw the guts of a 16gb (no screen assy) go for $41 the other day.
As for an SDHC card, don't know. You'd probably have to connect it the same way as the OTG connector (pwr & Data). You'd still need the switch or OTG plug to get the TP to check the bus, the 5v step up to pwr it, some sort of micro-Sd "socket (so there's room for the switch) and an app like "StickMount" to mount it for use. Ultimately, it'd still be OTG but without the option to connect anything else. I'd recommend the OTG port instead.
Edit: I updated Part 4 pictures with a fillet around the port and added a link to the OTG Tips & Tricks Thread (Evo3D)

i saw the orig post you referred to in your OP..
altho i like it very much and admire your work, i will never
be qualified to attempt it..
i just wonder why the cable still has to run outside from your new usb port to the micro usb port.
is it stupid to ask why it could not permanently connect from the inside and use a switch for charging / data transfer ?
again, i will never be able to do this so you could ignore this post..
also, from your evo 3d thread, i see that someone uses a 4 port 12000mah
battery charger for data... is this correct?..
i use a solar powered 4 port hub but would like to see a battery charger modded to charger / data transfer w/ a switch..
the solar hub of mine doesnt last so long
thanx foryour reply..

amkaos said:
i just wonder why the cable still has to run outside from your new usb port to the micro usb port.
is it stupid to ask why it could not permanently connect from the inside and use a switch for charging / data transfer?
Click to expand...
Click to collapse
Look closer at the USB Board post pictures. If the OTG switch wire is connected to the board internally, then no external setup is needed. I damaged the board just enough that I couldn't finish it until I can locate another board.
Others may not be willing to attempt the board soldering and choose only a full size power port (or microUSB) that needs the external cable that provides power back to the otg device plugged into the original port.
Sent from my "Up all night, Sleep all day" EVO3D!

mpgrimm2 said:
Look closer at the USB Board post pictures. If the OTG switch wire is connected to the board internally, then no external setup is needed. I damaged the board just enough that I couldn't finish it until I can locate another board.
Others may not be willing to attempt the board soldering and choose only a full size power port that needs the external cable that provides power back to the otg device plugged into the original port.
Sent from my "Up all night, Sleep all day" EVO3D!
Click to expand...
Click to collapse
thanx for the explanation.. i get it now..that makes so much sense
do you know what i was speaking of relating to the mod to a battery charger to switch between charge / otg ?
if possible to do , i could attempt that mod

amkaos said:
also, from your evo 3d thread, i see that someone uses a 4 port 12000mah
battery charger for data... is this correct?..
i use a solar powered 4 port hub but would like to see a battery charger modded to charger / data transfer w/ a switch..
the solar hub of mine doesnt last so long
Click to expand...
Click to collapse
I'm not sure what u mean by this. Post some links or quote the post and I will see if I can figure it out.
Sent from my "Up all night, sleep all day" HP CM9 Touchpad

shoot... sorry i thought i did link...
http://forum.xda-developers.com/showthread.php?t=1916638
to me , this is interesting because the OP shows a modded OTG cable to connect the mini port on his solar hub to the micro port of his evo3d..
this eliminates one cable:: from hub mini port to OTG usb..
he does say how it works but i dont know if the mod would be exactly the same for our HPTP..
i have that same self powered hub and it works fine.. just not much run time.. maybe 700mah.. iirc
secondly post #2 in that thread speaks of his 12000mah charger. it seems to me like he modded it to do OTG..
this would be good because of how much run time it would have..
could be great if he put on the charger a switch for charge / data transfer if it would need a switch to use like that..
anyway your current mod is soo ambitious but i saw you modded a wall charger ..
thanx again

OK I see what he did with the charger. It uses an adapter (host) cable to go from the main hub port to the PC (mini-USB to full size USB-A).
It looks like he spliced the micro-USB OTG cable (pin 4&5 shorted) to a mini-USB cable, and made a custom OTG Host cable. He mentions he disconnected/broke the +5v wire to prevent it charging the phone due to the small battery in it. I wouldn't do that myself, but I'd also ideally want a 3000-4000mah Solar Hub to modify for OTG & keeping the phone/tablet charged.
Have a look at my OTG cable schematics in reference post 9 above, particularly cable 1.
Sent from my "Up all night, sleep all day" HP CM9 Touchpad

mpgrimm2 said:
OK I see what he did with the charger. It uses an adapter (host) cable to go from the main hub port to the PC (mini-USB to full size USB-A).
It looks like he spliced the micro-USB OTG cable (pin 4&5 shorted) to a mini-USB cable, and made a custom OTG Host cable. He mentions he disconnected/broke the +5v wire to prevent it charging the phone due to the small battery in it. I wouldn't do that myself, but I'd also ideally want a 3000-4000mah Solar Hub to modify for OTG & keeping the phone/tablet charged.
Have a look at my OTG cable schematics in reference post 9 above, particularly cable 1.
Sent from my "Up all night, sleep all day" HP CM9 Touchpad
Click to expand...
Click to collapse
hi
so his phone supports data / charging at the same time?
but to mod an OTG cable for hptp and the mini usb port Hub, we just need to replace the usb end?
and leave pins 4 and 5 as they are?
How else would you make it instead..
I looked everywhere for a better self powered hub whether replaceable battery or not and would have liked to find something better.
thanx.. maybe I can try to make one

Related

[Q] Will this work ?

Just wondering if a typical cell charger can provide enough power to power these three things. (or if it will even work properly)
1 The Phone
2 A USB flash drive
3 HML adapter
What I want to do is connect power to the USB splitter male (I already have a wall plug to USB female adapter) then with the USB female ends I will connect a USB flash drive and then use a male USB to male micro-USB cable to power the MHL adapter. The phone goes to the other micro-USB end of the MHL adapter.
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I want this for two reasons. 1 So I can play media from a flash drive to a TV or monitor and 2 (if this will even work) use it to connect a USB to XLR cable so that I can record with a better quality microphone to my phone.
I realize that the phone being able to recognize and use the flash drive or microphone may be an issue but I can take a chance on that if nobody can confirm if it will or will not work.
BTW: if you have not already noticed, we are finally starting to get some reasonably priced MHL adapters on fleabay now. They are ranging from around 20-26 CAD (one in picture is 26)

I would like to know as well, as that sounds like a great alternative to carrying around DVD's and stuff, maybe even an externally powered harddrive, would need extfat or ntfs support though for large files.
Sent from my GT-I9100 using XDA Premium App

Linux reads NTFS hard drives and flash drives fine, so I am hoping that Android should also.
I was planning on getting the MHL adapter regardless anyway, and the other cables that I would need would only be like 10 bucks. So I am wanting to try it out since, like you say, opens up more options for portability that may replace other devices or at least take up less space.
I was mainly looking to see if I would hear a show stopper of why not to do this, like if this set up could damage something that is connected.

K3VL4R said:
Linux reads NTFS hard drives and flash drives fine, so I am hoping that Android should also.
I was planning on getting the MHL adapter regardless anyway, and the other cables that I would need would only be like 10 bucks. So I am wanting to try it out since, like you say, opens up more options for portability that may replace other devices or at least take up less space.
I was mainly looking to see if I would hear a show stopper of why not to do this, like if this set up could damage something that is connected.
Click to expand...
Click to collapse
You will need a proper usb to go cable to connect the flash drive or hdd, i have connected a flash drive to my phone without any problems..
I would think you would need a custom kernels or ntfs-3G modules for the kernel you are using.
The big thing is if the phone can deal with being charged, output hdmi and connect to a HDD over the same usb port at the same time?
Maybe a powered hub?
Also wondering if there would be enough bandwidth on the bus to support that all.
The big thing that would be good for me is that I could buy a cheap self powered hdd, load it up with movies and stuff and watch it while at work where there's a lot of down time, and being able to charge and use tv out at the same time would mean I could watch the iplayer or something on the tv without having to worry about battery life!
Hey, connect a mouse and keyboard as well and your phone is basically a normal computer!
Sent from my GT-I9100 using XDA Premium App

Good idea. This powered hub is almost as cheap as the splitter cable and should take care of any power requirements.
As for the on-the-go cable, I have different angled micro male to usb female cables already so that I can help take stress off the jack when using it while charging. My USB flash drive does not power up with this cable. I just assumed it needed external power. What is different about the OTG cable, did they twist some wires or are mine just meant for charging if they are not working ? All the pins are present and the cable is thick, so no reason why they would not just connect everything internally.
Thanks for the replies so far.

K3VL4R said:
Good idea. This powered hub is almost as cheap as the splitter cable and should take care of any power requirements.
As for the on-the-go cable, I have different angled micro male to usb female cables already so that I can help take stress off the jack when using it while charging. My USB flash drive does not power up with this cable. I just assumed it needed external power. What is different about the OTG cable, did they twist some wires or are mine just meant for charging if they are not working ? All the pins are present and the cable is thick, so no reason why they would not just connect everything internally.
Thanks for the replies so far.
Click to expand...
Click to collapse
In order for usb to go to work you need a special cable, its got a special pin that's grounded or floating or has a few different values depending, the cables are very cheap on eBay or there's guides on how to make them.
OTG won't work with generic cables im afraid.
I just want this idea to work myself :d
Sent from my GT-I9100 using XDA Premium App

Im sitting here with a SGS2 with a USB kb, mouse, and a flash drive connected to it.
SGS2> (usb to go cable) > Powered hub > Mouse + keyboard + flash drive.
To get random devices to work (not hubs, input devices) you will need to add the device ids, see this thread for more info, more info and some device/vendor ids and a huge list of almost every device/vendor id
Attached is a rules file with logitech and some other vendors, add and expand as needed!
Now I need to buy a micro USB > many micro USB's and a mhl cable!
The powered hub is a must or stuff just wont work due to the power draw.
Im looking at picture of the MHL adaptor, and they all have a USB port for passthough, so we can defo at the very least charge while outputting via it.
The big question now is if you can daisy chain and do MHL and OTG at the same time!
Well, unless on a lucky chance the USB port will work with a splitter, you cant do MHL and OTG at the same time. A real shame

Thanks for the updates and links veyka. It also looks like the OTG cables do not charge the phone with the jumpered pins, so I will have to make sure and mark the OTG cables when they get here.
I should have the rest of my cables arrive in about 2-3 weeks and will post an update of what will or will not work. Sounds like the OTG cable alone should work with the USB to XLR cable for a microphone, as long as I can find a way to get the phone to recognize it. Though it would be nice to charge at the same time as well which the OTG does not support.
Do you know off hand what the headphone jack will accept for inputs ? Will it take TRRS or TRS audio in as well ? I am just looking at more options for XLR to the phone for connectivity without needing a mixer. Then I will use a mixer as well to see how much of a difference the balanced XLR out will make.

K3VL4R said:
Thanks for the updates and links veyka. It also looks like the OTG cables do not charge the phone with the jumpered pins, so I will have to make sure and mark the OTG cables when they get here.
I should have the rest of my cables arrive in about 2-3 weeks and will post an update of what will or will not work. Sounds like the OTG cable alone should work with the USB to XLR cable for a microphone, as long as I can find a way to get the phone to recognize it. Though it would be nice to charge at the same time as well which the OTG does not support.
Do you know off hand what the headphone jack will accept for inputs ? Will it take TRRS or TRS audio in as well ? I am just looking at more options for XLR to the phone for connectivity without needing a mixer. Then I will use a mixer as well to see how much of a difference the balanced XLR out will make.
Click to expand...
Click to collapse
In the end android should support anything linux does, you might need to build a kernel module (driver) or find someone that will for you.
You can get pretty much any input device going with the links above, but other stuff, I dont know im afraid
Hope lives eternal.
No clue im afraid

No problem bud. You have been more than helpful already. I already have a plethora of cables and devices for recording on laptop and PC with Windows and Linux. My Android uses for recording are so far purely just for practicing so that I have it down in case something of interest is created. So ease of use and portability is the main factor.
It also interested me just to be able to find different ways of recording since so much of it is done through software these says. The more knowledgeable I am with cables, signals and processing, the more options that I will have available to me. Though I still like to mic an amp then process afterwards.

HOW TO: $15 stand alone powered USB dongle for touchpad

I made a USB dongle that plugs into the USB port on the touchpad and provides a powered female USB-A port. It is basically a portable USB charger/battery with an OTG cable soldered to the USB port. Attached is a quick pdf showing the process. It's much smaller and more portable than using a y-cable and powered hub or battery pack.
The charger is $13 on Amazon with free prime shipping and OTG cables around $2 on ebay.
It's nice because it's small and I can secure it to the my case with a rubber band, providing a quick connection to a keyboard/mouse or usb flash drive. The particular charger charges via any powered USB port with a provided cable.
This is the battery pack I ordered, note the picture on the amazon page is not 100% accurate:
http://www.amazon.com/T-Mobile-Port..._1_1?s=wireless&ie=UTF8&qid=1325984238&sr=1-1
This is the cable I purchased, there are cheaper ones, but they ship from China:
http://www.ebay.com/itm/Micro-USB-O...ccessories&hash=item1e69fbb3c5#ht_1336wt_1398

Would that be powerful enough to power external portable hard drive like WD Passport?

gedas5 said:
Would that be powerful enough to power external portable hard drive like WD Passport?
Click to expand...
Click to collapse
Unfortunately, I don't have the power specs on the battery pack. If I come across a USB-powered hard drive, I'll test it.

scarletwahoo said:
I made a USB dongle that plugs into the USB port on the touchpad and provides a powered female USB-A port. It is basically a portable USB charger/battery with an OTG cable soldered to the USB port. Attached is a quick pdf showing the process. It's much smaller and more portable than using a y-cable and powered hub or battery pack.
The charger is $13 on Amazon with free prime shipping and OTG cables around $2 on ebay.
It's nice because it's small and I can secure it to the my case with a rubber band, providing a quick connection to a keyboard/mouse or usb flash drive. The particular charger charges via any powered USB port with a provided cable.
This is the battery pack I ordered, note the picture on the amazon page is not 100% accurate:
http://www.amazon.com/T-Mobile-Port..._1_1?s=wireless&ie=UTF8&qid=1325984238&sr=1-1
This is the cable I purchased, there are cheaper ones, but they ship from China:
http://www.ebay.com/itm/Micro-USB-O...ccessories&hash=item1e69fbb3c5#ht_1336wt_1398
Click to expand...
Click to collapse
that looks nice.. but you re saying that its plug and play?..
you dont have to mount/unmount?
why didnt you get one w/ more usb ports?
your pics are clear.
i wonder how easy it is to do the battery hub like yours but w/ 4 usb ports

Nicely done, very good solution and tutorial. again excellent!!!!

amkaos said:
that looks nice.. but you re saying that its plug and play?..
you dont have to mount/unmount?
why didnt you get one w/ more usb ports?
your pics are clear.
i wonder how easy it is to do the battery hub like yours but w/ 4 usb ports
Click to expand...
Click to collapse
http://www.amazon.com/Solar-Powered-Battery-Charger-Adapter/dp/B006DVMW92
This hub has 4 ports, a battery plus solar charging. That said, if I buy it I'll probably just plug it directly into the OTG cable rather than solder them together. Then again my soldering can be a little rough.
- Sent from a Prime terminal using a friends account

So can we only use the Micro Usb OTG host to connect to a USB drive/keyboard?

tpcm said:
So can we only use the Micro Usb OTG host to connect to a USB drive/keyboard?
Click to expand...
Click to collapse
yes plus 10char

Deserves sticky, love mods like this even if not always practical.
Cant believe they didnt give the touchpad a powered usb host. I guess they figured people would have issues with not enough power or drain the battery too quick with it.
So I think when I have some spare time I may mod your mod and show how to make a powered usb host that plugs into the wall charger so when your "docking" somewhere to charge you can hook up a keyboard and use it without restriction and even be charging the touchpad at the same time.
Probably don't even need to be too creative a proper Y cable may do the trick out the gate. Just to track one down.

Probably a stupid question, but it wouldn't be my first one...
Could you simply use a USB male-to-male cable to go between the battery pack and the OTG cable? Eliminate the soldering that way?
Or am I missing something?

I found a cable that I think will work perfectly for my idea of doing this from the charger instead of from battery: http://www.dealextreme.com/p/usb-fe...gb-tf-card-card-reader-kit-for-xtc-clip-82289
You can do it much cheaper with adapters and a regular y adapter though, and you may want to do so, so that you can have a longer cable from the charger to the y split, but yeah I will try this out sometime soon and let you know how it works.
The charger probably gives enough power to easily run things like a external HDD and such while the battery pack may not.

@Vicious ... couldn't that possibly put too much power to a USB device? Just saying since it is probably meant to be hooked up to a regular USB 5v port and (I don't know the specifics but) the touchpad USB power adapter has a high AMP output (might be talking sht here).

Nothing to worry about a device only "pulls" the amperage it needs so you can have extra with no harm to the device. It is the voltage that needs to match and usb is standard 5v.
Having too little amperage can actually cause a device harm due to malfunction, like a head crashing on a 2.5" hdd during use or a thumb drive failing to flash properly corrupting a sector.
I feel anybody that uses the touchpad in a docked setting that wants to use a keyboard may very well make use of my idea, that I of course got from the OP's idea.
I'll part it out for the cheapest way to make it without any cutting/soldering and test it soon enough.

mountaindewmi said:
@Vicious ... couldn't that possibly put too much power to a USB device? Just saying since it is probably meant to be hooked up to a regular USB 5v port and (I don't know the specifics but) the touchpad USB power adapter has a high AMP output (might be talking sht here).
Click to expand...
Click to collapse
That cable will work fine. I wasn't doing anything special, only eliminating the y-cable. I mainly wanted a small form factor way of adding a USB port to my case for portability. Now I can put a movie on a usb drive and watch it on the go.
You generally don't have to worry about using a supply that is to powerful. As long as the voltage output is 5 V, the device will only draw a certain current and consume the corresponding amount of power. The rating on a constant voltage supply is simply the maximum current it can provide, the amount it provides depends on the properties of the device.
Say you have a device, it states it operates at 5 V and draws 100 mA of current. That means the impedance of the device is R = V / I = 50 ohms. So if you use a 5 V supply rated to at least 100 mA, the device will only draw 100 mA. The supply can be rated for 100 mA or 1000 amps, it does not matter. (Although you wouldn't want to use 1000 A source as if something breaks or shorts it can draw a higher current)
Wikipedia "ohms law" if you are not familiar.

I tried to do this but can't get it to work, the touchpad shows the charging battery icon only it's not charging, and running dmesg it say source=charger mA=100 and usb otg exited low power mode and then right after says it entered low power mode... Not sure what the issue is...
edit: I'm thinking it may be my soldering work, gonna give it another pass...

joenathane said:
I tried to do this but can't get it to work, the touchpad shows the charging battery icon only it's not charging, and running dmesg it say source=charger mA=100 and usb otg exited low power mode and then right after says it entered low power mode... Not sure what the issue is...
edit: I'm thinking it may be my soldering work, gonna give it another pass...
Click to expand...
Click to collapse
You may have the two data pins shorted together. To the best of my knowledge, this tells the touchpad to go into charging mode. The touchpad charger does this, because in order to charge, it must draw more power than USB ports are designed to provide.
You need to remove the two resistors circled in the PDF. These keep the data pins shorted together as well.

This is a really great idea I think I might try it and your tut is very well explained thanks for taking the time out to put it all together
Thanks

Mouse works fine, keyboard hasn't been tried yet. How do you access a flash drive through this? What are the steps?

If you just cut out the resistors in the battery hub, could you just use the TP's regular cable to plug into one of the ports on the hub?

tpcm said:
Mouse works fine, keyboard hasn't been tried yet. How do you access a flash drive through this? What are the steps?
Click to expand...
Click to collapse
Stick mount works great
Sent from my CM9 TouchPad

[Tips and Tricks] OTG (USB Host Support) - Requires kernel support

Some kernels for the Evo 3D on XDA now have On-The-Go (OTG) USB host support built-in so it's very easy to support USB peripherals such as keyboards, mice, flash drives and portable hard drives from your phone regardless of the ROM installed. If you would like more information about OTG, here's a very good thread in the XDA Sensation forum that covers it pretty well.
The commands to mount and unmount USB storage devices manually are covered in that thread, but I've found the easiest way to mount and dismount my flash drive is to use an app called [root]StickMount from Chainfire, the developer of SuperSU. Depending on the ROM installed, it may not be considered compatible and won't show in the Play Store, so I've attached the .apk in case that happens.
I haven't used devices other than flash drives so far on my phone, but other users have indicated that keyboards, mice and other USB devices also work. If you are using OTG to attach any type of USB devices, please share your experiences and any tips you might have. Also, please use this thread for any questions you might have about OTG support and devices, even if you haven't gotten around to trying it yourself yet.
Other XDA threads about OTG related stuff:
Solar powered USB hub (kinda cool)
usb otg cradle
Nitty gritty OTG hardware discussion
Post with diagram of OTG connections
Thanks to mpgrimm2 for suggesting that we share this information from another site (there's actually more over there ).
ramjet73

I want to thank Markmx6 for his guide on another site that was easy for me to follow to make my own OTG cable and Ramjet73 for digging up and posting his links here. Maybe Markmx6 will add his info over here now too since all this works with the Buttered Toast Kernel (bigwillyg).
I got to looking around and wondering with the parts I have if I am setup for OTG and just need to plug everything together without hacking up a power supply which I'd prefer not to do.
Here's what I have on hand:
I ohmed out the " CrazyOnDigital 2 port charger's" data pins:
Port1-pin3 & port2-pin3 = 0.1 ohms (and about 30k to gnd/shld)
Port1-pin2 & port2-pin2 = 0.1 ohms (and about 30k to gnd/shld)
(I also reversed the leads in case I was reading through a diode)
So it looks like the data pins on this aren't shorted together and that it will function as a Powered USB "y" cable/pass through between ports 1 & 2.
Part 2
I realize that my purchased USB OTG cable won't plug in between the charger & my phone so I may use a USB extension Cable and USB A to A adapter that I have (not pictured) or I may just hack a spare USB A to Micro USB (5pin) cable that I have into another OTG Cable.
Q: My understanding is that an OTG cable has the ID pin (pin 4 of the 5pin Micro) tied to Gnd, like Markmx6 did in his original cable; correct? So, that's why the micro USB end gets cut open a bit.
A: Yes.
----------------------------------------------------------------
My Additional References:
Zoom [DIY] MicroUSB Host Cable
So in a normal micro/mini USB cable, there are 4 wires, 5 pins.
1. Red - V+
2. White - Data -
3. Green - Data +
4. Empty
5. Black - Ground
That micro male to mini female cable above has the 4th (5th?) wire, brown. This is the ID wire. Shorted to ground, it makes the cable a host cable.
Click to expand...
Click to collapse
Wikipedia's: USB On-The-Go page
The OTG cable has a micro-A plug on one side, and a micro-B plug on the other (it cannot have two plugs of the same type). OTG adds a fifth pin to the standard USB connector, called the ID-pin; the micro-A plug has the ID pin grounded, while the ID in the micro-B plug is floating. The device that has a micro-A plugged in becomes an OTG A-device, and the one that has micro-B plugged becomes a B-device. The type of the plug inserted is detected by the state of the pin ID .
Three additional ID pin states are defined[4] at the nominal resistance values of 124 kΩ, 68 kΩ, and 36.5 kΩ, with respect to the ground pin. These permit the device to work with a USB Accessory Charger Adapter which allows the OTG device to be attached to both a charger and another device simultaneously.[6]
These three states are used in the cases of:
- A charger and either no device or an A-device that is not asserting VBUS (not providing power) are attached. The OTG device is allowed to charge and initiate SRP but not connect.[6]
- A charger and an A-device that is asserting VBUS (is providing power) are attached. The OTG device is allowed to charge and connect but not initiate SRP.[6]
- A charger and a B-device are attached. The OTG device is allowed to charge and enter host mode.[6]
Click to expand...
Click to collapse
Micro-USB connector pinout
-----------------------------------------------------
Part3: SUCCESS! (with Otg Enabled kernel)
I went ahead and modified a spare USB A to Micro B cable for OTG without power. Plugged everything up with my Logitech Wireless USB mouse and it works! Cool as can be! See new pics. (Yellow wire is the Jumper).
Still have a few questions:
Q: Would the "purchased" OTG Cable already have pin 4 & 5 Shorted?
A: YES it should, but one of the cables I bought was defective.
Q: Does your OTG setup from the op charge the phone at the same time (and/or keep it charged)?
A: Yes
Edit: Apparently I broke the +5v wire during reassembling the cable. See next post.
(SEE UPDATED POSTS FARTHER DOWN)
EDIT:
In Relation to my Following Posts, I have patched together the following cable schematics as a reference to the cables I have either made or purchased.

If you have the ability & willingness to find out what the ID pin resistance is in your "Accessory" device as mentioned below please let me know. I am trying to correlate the info from the Wikipedia/USB OTG reference to all the available ID pin states.
Mpgrimm2; I have a small update from some of my testing regarding the USB OTG 4 ID pin states (pin 4 to pin 5 "gnd" ).
Ininity (Open) = Standard USB data/charge
0 Ω (shorted) = USB OTG host
36.5K Ω = desktop cradle/dock
(my seidio actually has a 47k Ω resistor said:
Anyone want to open their car dock and check the resistor?
Anyone want to open their MHL adapter & check the resistor on that too?[/COLOR]
Wikipedia's: USB On-The-Go page
Click to expand...
Click to collapse
Here's what I've found out or verified:
- I'm still not sure about the 3 different USB OTG ID modes that were mentioned. In the test rig (pictured) for different values of resistance between pin 4 (ID) and pin 5 (gnd):
0 ohm (Short) = USB OTG host
36.5k ohm (47k in use) = Dock Mode
68K ohm (74k in use) = Dock Mode
124k Ohm (127k in use) = No discernible effect
I also determined that my first homemade USB OTG cable wouldn't allow the phone to charge because of a broken +5v wire during reassembly (new one works correctly, but so far I preferred the simplicity of the original setup & charger over the new cable I made, but time will tell.
Here's the Ebay link to the OTG cable RamJet73 recommended (same as the last one I made b/c I didn't want to wait) so that I can keep it linked in one place.

Here are the pictures of the 2nd cable that I made that is "very similar" to the one Ramjet73 mentioned at eBay but 2ft longer (See Schematic #4 in later post).
Keep in mind that the OTG function will be disabled if an OTG cable is plugged into a USB charger that has the data pins shorted internally (AC charging), but this doesn't appear to happen with a powered hub (isolated)

Markmx6's "Homemade Powered OTG Cable" Part 1
I got permission from Markmx6 to repost this here:
Markmx6; said:
First off, I am not responsible for you screwing up your phone, shorting your house out, frying your SD card, burning down your home, or anything else that may or may not occur from you building this...
Tools you will need: Razor blade, Soldering iron, Solder, Super glue.
Optional tools: Dremel with cut-off wheel.
I started with components I imagine you will all have, since they came with the phone. The HTC charging cable and outlet adapter.
First, cut around the base of the outlet adapter. This is around 3/16" thick, and the cut is better off to be made on the "shiny" plastic than the "dull" portion. I used a Dremel, but any type of blade will do, it just may take more time.
Make a cut along the white line on the board (Shown in red here) Otherwise this will not work. On typical chargers they short out the Data+ and the Data- connections (mpg2 edit: it forces "AC Charging" mode). Not sure why... Digging a razor blade across this several times should do the trick, but if you want to make sure with a continuity tester that will always give piece of mind.
Now you need to cut your cable, I recommend leaving around 2" or more from the standard usb side. (A little of this wire will come in handy for later in this project)
Cut and then strip your wires, there will be a braided shielding wire just under the insulation. Then it will be helpful to "Tin" the ends of your wires.
The shielding can be completely removed, or you can ground it out, but I haven't found this to be needed.
You will now need to solder the wires to the circuit board. This will obviously need to be in the correct order.
From the top will be:
RED = 5V+
WHITE = Data +
GREEN = Data -
BLACK = 5V-
Now you can re-assemble the Outlet adapter if you choose.
Now you need to cut up the other (phone) end of your cable to enable the OTG function.
Post 2 will outline this.
Click to expand...
Click to collapse

Markmx6's "Homemade Powered OTG Cable" Part 2
Markmx6; said:
Carefully cut down the sides of the connector, if you can do this in one clean cut it will be helpful when you re-attach then after your modifications.
Carefully cut away the plastic, and what looks like hot glue. You need to expose the side that has a blank terminal. and the one on the other side that has a black wire.
Pins 4 and 5 need to be attached, so a small piece of wire (from the leftover ends of the cable comes in handy) works really well.
It doesn't really show up in the pictures though
Now re-glue the pieces from the end of the cable back onto the connector
That is all.
I am using 3.2.8otg for a kernel and negalite2.9 and otg helper and everything works as it should.
http://forum.xda-developers.com/showthread.php?t=1588979
For usb storage you need to have all of the cables hooked up before you insert the SD card.
Click to expand...
Click to collapse
NOTE: Bigwillig's [Kernel] ButteredToasT ICS RLS 04 | Linux 3.0.46 | linaro 4.7 -o3 | otg | HTC beats also supports OTG with any rom that will boot the kernel.
Sent from my "Up all night, Sleep all day" EVO3D!

Ebay/Applecable Purchased OTG Cable & USB Hub
I just verified that if you get the Micro USB Host OTG Cable With USB power ($6 from AppleCable on Ebay) that Ramjet73 mentioned (or this one), it will work with any standard USB charger (ie the 1 Amp HTC or 2 Amp HP Touchpad Charger) because the USB Power Connector is Isolated. I also picked up Applecable's USB 2.0 3 Port Hub with data Sync Charger cable for $7
(I may try to modify it to be a USB OTG powered hub with this OTG Adapter and this USB to 3.5mm/1.3mm Adapter to power the hub directly from "ANY" USB charger.
EDIT: It works fine, but modified it anyway).
Here's some updated AppleCable Ebay Store links (4-18-14):
Micro USB Host OTG Cable With USB power
USB 2.0 3 Port Hub with data Sync Charger cable (not OTG, but a cheap hub that works. can be modified for OTG)
Micro USB Host OTG Cable w/micro USB power
Left Angled Micro USB Host OTG Cable w/USB power
Right Angled Micro USB Host OTG Cable w/USB power

^^^
been looking for something like this!! post back on your progress

mpgrimm2 said:
I just verified that if you get the Micro USB Host OTG Cable With USB power ($6 from AppleCable on Ebay) that Ramjet73 mentioned (or this one), it will work with any standard USB charger (ie the 1 Amp HTC or 2 Amp HP Touchpad Charger) because the USB Power Connector is Isolated. I also picked up Applecable's USB 2.0 3 Port Hub with data Sync Charger cable for $7 (I may try to modify it to be a USB OTG powered hub with this).
Click to expand...
Click to collapse
I just found out that the version of the OTG cable with the female microUSB connector doesn't charge the phone when power is applied to that connector. The eBay listing at your link above doesn't say one way or the other, but this link was posted on another site and that listing specifically says it doesn't. I'm not sure why that is, but it looks like the same brand (Chen Yang) in both listings.
The version with the male USB A connector for power can definitely charge the phone when in use. I've tested that myself.
ramjet73

Now that I've made a few on my own and bought the one you recommended, I can say it likely has to do with the way that it's wired up. I would bet that the Applecable one with the M & F microUSB allows charging.
Note: I also updated my previous post with a new USB to 3.5mm adapter for the hub. I ordered both adapters (so I don't have to cut/solder mods to the hub) and will report back once I get it. (also picked up a 2nd 3d for my son's b-day coming up so I don't waste an upgrade just yet).

Edited

I just don't get it... Found many usb hubs with internal rechargeable batteries, but all are old posts, not available for sell anymore . Why is it so complicated for Evo 3D to connect usb to it? I really want to connect my Razer Banshees to it, but all this running around to find a usb hub with internal battery is killing me, and having one that works on charger is ilogical, from my point of view. If i want to do this, I want it to be portable, otherwise I'd just connect it to my pc/laptop. I connected them to a Galaxy S3 and they worked instantly. I use Coolexe's ROM and Kernel (v4.0), and it says that it has usb support and usb headset support

posedatull said:
I just don't get it... Found many usb hubs with internal rechargeable batteries, but all are old posts, not available for sell anymore . Why is it so complicated for Evo 3D to connect usb to it? I really want to connect my Razer Banshees to it, but all this running around to find a usb hub with internal battery is killing me, and having one that works on charger is ilogical, from my point of view. If i want to do this, I want it to be portable, otherwise I'd just connect it to my pc/laptop. I connected them to a Galaxy S3 and they worked instantly. I use Coolexe's ROM and Kernel (v4.0), and it says that it has usb support and usb headset support
Click to expand...
Click to collapse
Unlike Samsung, HTC hasn't officially supported OTG so we are lucky to have some ROM's and kernels that do support it. Even the utilities like stickmount don't download from the Play Store because the Evo 3D is not considered a compatible device.
USB mice and keyboards can work without external power, but many other devices need power and would drain the phone battery very quickly even if they could use it. I have no experience with USB headphones on a phone, but it would make more sense to me to have batteries in the headphones and not depend on the phone for power. Another possibilty may be to use an external battery like this one connected to an OTG adapter that includes a connector for external power, but I haven't test that.
I use rechargeable stereo bluetooth headphones so I don't have to mess with cables at all, but if you prefer the USB headphones the options may be more limited with the Evo 3D than the SGS3.
ramjet73

Between the items Ramjet73 and I have mentioned in previous posts (edited below), you should be able to piece together the functionality you are looking for, but still not ideal as far as portability. Markmx6 has mentioned making his own "D" battery powered usb hub (I think) that he may post here sometime. Hope this helps.
mpgrimm2 said:
I also picked up
this USB 2.0 3 Port Hub with data Sync Charger cable for $7
this OTG Adapter
this USB to 3.5mm/1.3mm Adapter to power the hub directly from a USB port/charger).
Click to expand...
Click to collapse
ramjet73 said:
Another possibilty may be to use an external battery
like Rechargeable USB Universal Battery connected to an OTG adapter that includes a connector for external power, but I haven't tested that.
Click to expand...
Click to collapse
Good find Ramjet73! Got me thinking about options again, just waiting on my parts to get here. Mind if I paste this into the other sites thread?

Saw this app posted in the Buttered Toast thread and may give it a try for NTFS support:
mnomaanw said:
You can mount NTFS drives with this App ----> https://play.google.com/store/apps/details?id=com.paragon.mounter&hl=en
I think it can mount exFAT also.
Click to expand...
Click to collapse

posedatull said:
I just don't get it... Found many usb hubs with internal rechargeable batteries, but all are old posts, not available for sell anymore . Why is it so complicated for Evo 3D to connect usb to it? I really want to connect my Razer Banshees to it, but all this running around to find a usb hub with internal battery is killing me, and having one that works on charger is ilogical, from my point of view. If i want to do this, I want it to be portable, otherwise I'd just connect it to my pc/laptop. I connected them to a Galaxy S3 and they worked instantly. I use Coolexe's ROM and Kernel (v4.0), and it says that it has usb support and usb headset support
Click to expand...
Click to collapse
I built a 4 port charger using four "D" batteries for a trip I took to Disney world (five kids on a six hour flight.... required someway to recharge Nooks, cell phones, and etc)
To break it down simply I used a four battery holder. (Apparently I don't have enough posts to post links, pull up radioshacks website and search for "D" battery holder)
You don't need "D" batteries as these are bulky, I used them because size wasn't really a factor. "AA" or "AAA" batteries should be fine. Remember Alkaline batteries provide 1.5 volts each NiCad (Older rechargeable) 1.2 volts There are newer voltages to my knowledge...
I used four batteries because it produces 6 volts in series. MAY POSSIBLY DAMAGE YOUR PHONE
Ideally you would provide 5 volts which is what USB provides, I find 6 volts worked fine for me.
For my charger I shorted the DATA +/- terminals together to fool the phone into believing it was using AC power for a faster charge.
All you really need to do to continue to use the hub as a Data transfer device would be to solder the red and black wires to their respective terminals on the hub, it shouldn't matter which port you use as they should all be linked, other hubs may vary.
You may also be able to just wire a female USB port onto the battery holder and use a hub plugged into that...

My CrazyOnDigital 2 port charger doesn't have the data pins shorted (D+ and D-) like the stock HTC unit. This causes any "Android" phone to charge at the lower 500ma Max "Charging USB" rate vs "AC Charging" (explains my slow charging when travelling), but a bonus is that it allows me to pass data b/w the 2 ports like a simple hub.
- If the D+ and D- pins are shorted when an OTG USB cable is plugged in, the phone will go into "AC Charging" mode, but not allow OTG devices to work, but if the phone is still connected and the data pins opened back up, you retain "AC Charging" mode and have USB OTG functions.
(I'm thinking that a simple on/off switch installed across the data pins of my charger will give me a dual mode charger).
---------------------------------------------------------
AC CHARGING / USB CHARGING (Data Pass Through) MOD 12-1-12
- I got tired of having a 2 port 2 Amp charger that only allowed 500ma "USB Charging" with Android & OTG. See pix:

mpgrimm2 said:
I just verified that if you get the Micro USB Host OTG Cable With USB power ($6 from AppleCable on Ebay) that Ramjet73 mentioned (or this one), it will work with any standard USB charger (ie the 1 Amp HTC or 2 Amp HP Touchpad Charger) because the USB Power Connector is Isolated. I also picked up Applecable's USB 2.0 3 Port Hub with data Sync Charger cable for $7
(I may try to modify it to be a USB OTG powered hub with this OTG Adapter and this USB to 3.5mm/1.3mm Adapter to power the hub directly from "ANY" USB charger).
Click to expand...
Click to collapse
And here is my new OTG setup with the modified charger (no need to modify the charger with this) and modified hub:
Also works well with [MOD] Self Powered USB OTG on the HP Touchpad! (v2 Full Size) 11-30-12

Just out of curiousity, will a sixaxis controller be supported by otg? Could anybody confirm this for me.

Jsparta26 said:
Just out of curiousity, will a sixaxis controller be supported by otg? Could anybody confirm this for me.
Click to expand...
Click to collapse
I saw someone taking about it in the HP Touchpad CM9 thread, I will see if I can find the post & report back.
update: post was here
-------------------------------------------
Separately, I saw this (couldn't find the u12000 solar hub mentioned previously)
Opteka BP-SC4000 Ultra Thin Solar Powered High Capacity (4000mAh) Backup Battery and Charger
I know some have mentioned an interest in an all in one OTG enabled solar powered charger with battery backup. Sounds easy enough with the correct parts.
Sent from my "Up all night, sleep all day" HP CM9 Touchpad

[INFO] HP TP USB OTG Notes, Tips, & Tricks (4-28-14)

[INFO] HP TP USB OTG Notes, Tips, & Tricks
DISCLAIMER: I'm not a dev, nor do I play one on t.v. Use the information and links at your own risk. READ and UNDERSTAND what your doing before flashing is the best bet. I take no responsibility or credit for the information.
This is a work in progress... Still gathering my notes for the thread.
Major Credit to @ramjet73 for working with me on the Evo3d OTG Tips & Tricks thread and allowing me to reuse the info here:
-----------------------------------------------------------------------------------------------------------------------------------
Other XDA USB OTG related threads:
Spunker88's HP Touchpad USB OTG Compatibility List
Solar powered USB hub (kinda cool)
Nitty gritty OTG hardware discussion
Mpgrimm2's [MOD] Self Powered USB OTG on the HP Touchpad! (v2 Full Size)
ramjet73 said:
For kernels that have On-The-Go (OTG) USB host support built-in, it's very easy to support USB peripherals such as keyboards, mice, flash drives and portable hard drives from your phone regardless of the ROM installed. If you would like more information about OTG, here's a very good thread in the XDA Sensation forum that covers it pretty well.
The commands to mount and unmount USB storage devices manually are covered in that thread, but I've found the easiest way to mount and dismount my flash drive is to use an app called [root]StickMount from Chainfire, the developer of SuperSU. Depending on the ROM installed, it may not be considered compatible and won't show in the Play Store, let me know if that happens and I will post the apk.
If you are using OTG to attach any type of USB devices, please share your experiences and any tips you might have. Also, please use this thread for any questions you might have about OTG support and devices, even if you haven't gotten around to trying it yourself yet.
Click to expand...
Click to collapse
A couple of quick FYI's about using USB OTG with the Touchpad:
- USB OTG has been possible on the HP TP since CM9 (or earlier?)
- To enable OTG on any android device, Pin 4 (I.D. Pin) needs to be shorted to Pin 5 (DC Return) on the host device. This is the function of "OTG" cables. Note that I have purchased OTG cables that didn't work because Pins 4 & 5 were not shorted/manufactured correctly. On some devices with 3.x Kernels, it is possible to enable USB OTG via a sysfs command (not the TP yet).
- The HP Touchpad is not capable of supplying 5v power out the microUSB port for OTG functions so a standard OTG cable WILL NOT WORK. You must use either an OTG Cable with Isolated External Power Plug, an externally powered USB Hub, or a modified USB Charger/Cable.
- Even though external power is required for OTG, earlier support for USB OTG on the TP would only allow a device that draws/reports 100ma or less (ie USB mouse, small thumbdrives, etc) to be active when directly attached to the primary msm_otg port of the TP (Not Sure if this still applies). This limit can be "bypassed" for larger draw devices (ie portable hard drives) by using an externally powered USB Hub in between the TP's OTG Cable and the device. The hub's "Host" end will report 100ma or less to the TP and allow up to 480ma devices to be plugged into the hub. Good. (Credit to AndroidLover at RootzWiki for this info)
- It is possible to make your own USB OTG Cable with Power, or modify some USB Chargers for OTG functionality if you have some basic soldering skills and equipment.
- Most "dedicated" android USB Chargers have the "Data" pins sorted to tell an android device to use "AC Charging" ("fast charge") instead of "USB Charging". This "prevents data communication and only allows charging. Without a correctly "isolated" OTG Power Cable, OTG will not work with most chargers. Some chargers will either have shorted data pins (i.e. HTC), a low resistance across the pins (i.e. HP) or an "Open" (nothing) across the pins (i.e. aftermarket "Apple" chargers).
- Recommended minimum apps to use with USB OTG:
StickMount, USB Device Info, USB Host Diagnostics, ES File Explorer (or Similar)

Purchase Links for USB OTG items I Use with my TP
I just verified that if you get the Micro USB Host OTG Cable With USB power ($6 from AppleCable on Ebay) that Ramjet73 mentioned (or this one), it will work with any standard USB charger (ie the 1 Amp HTC or 2 Amp HP Touchpad Charger) because the USB Power Connector is Isolated. I also picked up Applecable's USB 2.0 3 Port Hub with data Sync Charger cable for $7
(I may try to modify it to be a USB OTG powered hub with this OTG Adapter and this USB to 3.5mm/1.3mm Adapter to power the hub directly from "ANY" USB charger.
EDIT: It works fine, but modified it anyway).
Here's some updated AppleCable Ebay Store links (4-18-14):
Micro USB Host OTG Cable With USB power
USB 2.0 3 Port Hub with data Sync Charger cable (not OTG, but a cheap hub that works. can be modified for OTG)
Micro USB Host OTG Cable w/micro USB power
Left Angled Micro USB Host OTG Cable w/USB power
Right Angled Micro USB Host OTG Cable w/USB power

USB OTG Cable Schematics. HP TP Needs Cable 2 or Cable 3
If you are able and want to make your own OTG cable, use the schematic for cable 2 (or cable 3) as needed for the TP.
Here are some pictures of an earlier version I made (Cable 4, not recommended) as an example.

Markmx6's HTC USB Charger/Powered OTG Cable Mod Part 1 of 2 : (Reposted here with permission)
Markmx6; said:
First off, I am not responsible for you screwing up your phone, shorting your house out, frying your SD card, burning down your home, or anything else that may or may not occur from you building this...
Tools you will need: Razor blade, Soldering iron, Solder, Super glue.
Optional tools: Dremel with cut-off wheel.
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I started with components I imagine you will all have, since they came with the phone. The HTC charging cable and outlet adapter.
First, cut around the base of the outlet adapter. This is around 3/16" thick, and the cut is better off to be made on the "shiny" plastic than the "dull" portion. I used a Dremel, but any type of blade will do, it just may take more time.
Make a cut along the white line on the board (Shown in red here) Otherwise this will not work. On typical chargers they short out the Data+ and the Data- connections (mpg2 edit: it forces "AC Charging" mode). Not sure why... Digging a razor blade across this several times should do the trick, but if you want to make sure with a continuity tester that will always give piece of mind.
Now you need to cut your cable, I recommend leaving around 2" or more from the standard usb side. (A little of this wire will come in handy for later in this project)
Cut and then strip your wires, there will be a braided shielding wire just under the insulation. Then it will be helpful to "Tin" the ends of your wires.
The shielding can be completely removed, or you can ground it out, but I haven't found this to be needed.
You will now need to solder the wires to the circuit board. This will obviously need to be in the correct order.
From the top will be:
RED = 5V+
WHITE = Data +
GREEN = Data -
BLACK = 5V-
Now you can re-assemble the Outlet adapter if you choose.
Now you need to cut up the other (phone) end of your cable to enable the OTG function.
Post 2 will outline this.
Click to expand...
Click to collapse

Markmx6's HTC USB Charger/Powered OTG Cable Mod Part 2 of 2 : (Reposted here with permission)
Markmx6; said:
Carefully cut down the sides of the connector, if you can do this in one clean cut it will be helpful when you re-attach then after your modifications.
Carefully cut away the plastic, and what looks like hot glue. You need to expose the side that has a blank terminal. and the one on the other side that has a black wire.
Pins 4 and 5 need to be attached, so a small piece of wire (from the leftover ends of the cable comes in handy) works really well.
It doesn't really show up in the pictures though
Now re-glue the pieces from the end of the cable back onto the connector
That is all.
For usb storage you need to have all of the cables hooked up before you insert the SD card.
Click to expand...
Click to collapse
Sent from my "Up all night, Sleep all day" EVO3D!

I got to looking around and wondering with the parts I have if I am setup for OTG and just need to plug everything together without hacking up a power supply which I'd prefer not to do.
Here's what I have on hand:
I ohmed out the " CrazyOnDigital 2 port charger's" data pins:
Port1-pin3 & port2-pin3 = 0.1 ohms (and about 30k to gnd/shld)
Port1-pin2 & port2-pin2 = 0.1 ohms (and about 30k to gnd/shld)
(I also reversed the leads in case I was reading through a diode)
So it looks like the data pins on this aren't shorted together and that it will function as a Powered USB "y" cable/pass through between ports 1 & 2.
Part 2
I realize that my purchased USB OTG cable won't plug in between the charger & my phone (Schematic #1) so I may use a USB extension Cable and USB A to A adapter that I have (not pictured) or I may just hack a spare USB A to Micro USB (5pin) cable that I have into another OTG Cable.
Q: My understanding is that an OTG cable has the ID pin (pin 4 of the 5pin Micro) tied to Gnd, like Markmx6 did in his original cable; correct? So, that's why the micro USB end gets cut open a bit.
A: Yes.
----------------------------------------------------------------
My Additional References:
Zoom [DIY] MicroUSB Host Cable
So in a normal micro/mini USB cable, there are 4 wires, 5 pins.
1. Red - V+
2. White - Data -
3. Green - Data +
4. Empty
5. Black - Ground
That micro male to mini female cable above has the 4th (5th?) wire, brown. This is the ID wire. Shorted to ground, it makes the cable a host cable.
Click to expand...
Click to collapse
Wikipedia's: USB On-The-Go page
The OTG cable has a micro-A plug on one side, and a micro-B plug on the other (it cannot have two plugs of the same type). OTG adds a fifth pin to the standard USB connector, called the ID-pin; the micro-A plug has the ID pin grounded, while the ID in the micro-B plug is floating. The device that has a micro-A plugged in becomes an OTG A-device, and the one that has micro-B plugged becomes a B-device. The type of the plug inserted is detected by the state of the pin ID .
Three additional ID pin states are defined[4] at the nominal resistance values of 124 kΩ, 68 kΩ, and 36.5 kΩ, with respect to the ground pin. These permit the device to work with a USB Accessory Charger Adapter which allows the OTG device to be attached to both a charger and another device simultaneously.[6]
These three states are used in the cases of:
- A charger and either no device or an A-device that is not asserting VBUS (not providing power) are attached. The OTG device is allowed to charge and initiate SRP but not connect.[6]
- A charger and an A-device that is asserting VBUS (is providing power) are attached. The OTG device is allowed to charge and connect but not initiate SRP.[6]
- A charger and a B-device are attached. The OTG device is allowed to charge and enter host mode.[6]
Click to expand...
Click to collapse
Micro-USB connector pinout
-----------------------------------------------------
Part3: SUCCESS! (with Otg Enabled kernel)
I went ahead and modified a spare USB A to Micro B cable for OTG without power. Plugged everything up with my Logitech Wireless USB mouse and it works! Cool as can be! See new pics. (Yellow wire is the Jumper).
Still have a few questions:
Q: Would the "purchased" OTG Cable already have pin 4 & 5 Shorted?
A: YES it should, but one of the cables I bought was defective.
Q: Does your OTG setup from the op charge the phone at the same time (and/or keep it charged)?
A: Yes (Not Likely on the HP TP)
Edit: Apparently I broke the +5v wire during reassembling the cable. See pictures.

My CrazyOnDigital 2 port charger doesn't have the data pins shorted (D+ and D-) like the stock HTC unit. This causes any "Android" device to charge at the lower 500ma Max "Charging USB" rate vs "AC Charging" (explains my slow charging when travelling), but a bonus is that it allows me to pass data b/w the 2 ports like a simple hub.
- If the D+ and D- pins are shorted when an OTG USB cable is plugged in, the phone will go into "AC Charging" mode, but not allow OTG devices to work, but if the phone is still connected and the data pins opened back up, you retain "AC Charging" mode and have USB OTG functions.
(I'm thinking that a simple on/off switch installed across the data pins of my charger will give me a dual mode charger).
---------------------------------------------------------
AC CHARGING / USB CHARGING (Data Pass Through) MOD 12-1-12I am not responsible for you screwing up your device, shorting your house out, frying your SD card, burning down your home, or anything else that may or may not occur from you building this...
- I got tired of having a 2 port 2 Amp charger that only allowed 500ma "USB Charging" with Android & OTG. See pix:

Post 8 for me.

Originally Posted: 2/23/13
Q: Does anyone know for certain if it's possible on the touchpad to echo the OTG "mode" command (ie host vs none) ?
On the evo3d there is a sysfs command that can be "echoed" to enable OTG with any standard cable and I was able to get the Kernel Tuner dev to add a toggle in his app for it.
If I can find someone who knows & can verify the sysfs command for our CM touchpad's I can have him add it into the app easily (Apr2014 Edit: KT not currently in development).
Note: I haven't found it yet by digging around with EsFileExplorer and activating OTG with a cable.
Mpgrimm2 said:
Didn't know OTG could be activated (on the Evo3D) using a standard cable with a sysfs command like:
Code:
echo host > /sys/kernel/debug/msm_otg/mode
Options are "host" or "none" (maybe this command can get added to "kernel Tuner" app! ). Wonder if it's the same for the Touchpad.
Fyi, don't know how different it would be on each device (ie GS3 vs. Evo3d & HP Touchpad), but it looks like for the Touchpad on CM9 it's
Code:
/sys/kernel/debug/otg/mode
Click to expand...
Click to collapse
I realize some may say "why bother, just use an OTG cable", but if you look through my OTG mod thread, you will realize that it's one less wire to solder to a circuit board and will also allow any user to avoid buying the cable.
Note: I also posted this in my [MOD] Self Powered USB OTG on the HP Touchpad! (v2 Full Size) 11-30-12 thread.
Dorregaray said:
In kernels 2.6.39 and newer the sysfs entry is named msm_otg. We're using the 2.6.35 kernel where the entry is named otg. The available options are: none, peripheral and host.
It seems that the:
Code:
echo host > /sys/kernel/debug/otg/mode
command should work.
Click to expand...
Click to collapse
Mpgrimm2 said:
Thank you for the feedback.
Code:
/sys/kernel/debug/otg/mode
That's what I was thinking too, but I can't seem to see any change of state at that location when activating it with a shorted ID pin and the developer for Kernel Tuner indicated that he added the code for it which doesn't seem to work either.
When I check the mode file there isn't anything there (blank). I have also tried settings permissions for rwx-rwx-rwx and manually typing "host" and saving the file. It goes immediately back to a blank file.
Admittedly I'm an amateur and was trying to echo it with an /init.d script at one point (edited with EsFileExplorer), shouldn't that work? I will fiddle with it some more.
Click to expand...
Click to collapse
Dorregaray said:
First of all try to echo from a terminal app on running system and check if it works, check also the dmesg if there's no error there. If it will be working then you can add an entry to init.d script
Click to expand...
Click to collapse

Last one for me. Feel free to comment.

Trouble with OTG/Touchpad/DS4 controller
I hope someone can help me. I am trying to connect my Dual Shock 4 PS4 controller to my Touchpad via OTG, so I can use Remote Play for my games. I am rooted, using PAC MAN ROM 4.4.4RC-1. Through trial and error (and this forum), I discovered that a normal OTG cable will not work. So, I ordered and received my powered OTG cable in the mail from China (I found the link in this thread a couple of weeks ago). Unfortunately, the HP Touchpad still doesn't seem to recognize the DS4, so I want to make sure I am doing this correctly. Pictures of the cable are attached, along with my setup. The only thing missing from the pix is the connection of the male USB side of the cable to the iPhone wall charger (the cable is very short to get all in one picture). I lost the official Barrel charger 2 years ago, but the iPhone wall charger DOES charge my Touchpad when in Android mode, so not sure why it won't work for OTG connectivity.
1. I connect the DS4 to the micro-USB controller cable that came with the PS4.
2. I then connect the male USB side of that cable to the female USB of the powered OTG cable.
3. I then connect the micro-USB of the powered cable to the HP Touchpad.
4. I then connect the male USB side to the female iPhone wall charger (I lost the TP Barrel charger a couple of years ago).
And I get nothing. The DS4 seems to have no connectivity with the HP Touchpad using this method.
FYI: Again, I am rooted and running Pac Man Rom 4.4.4RC-1
The strange thing is that when I connect the Touchpad to the iPhone wall charger when it's on Android, it charges! So I don't understand why it's not working when connected to the DS4. Is the official Barrel charger the only one that will work? Do I need to install some app or software to get the DS4 to be recognized via OTG?
Any help you can provide would be greatly appreciated!
Thank you!

ConfusedTouchpad said:
I hope someone can help me. I am trying to connect my Dual Shock 4 PS4 controller to my Touchpad via OTG, so I can use Remote Play for my games. I am rooted, using PAC MAN ROM 4.4.4RC-1. Through trial and error (and this forum), I discovered that a normal OTG cable will not work. So, I ordered and received my powered OTG cable in the mail from China (I found the link in this thread a couple of weeks ago). Unfortunately, the HP Touchpad still doesn't seem to recognize the DS4, so I want to make sure I am doing this correctly. Pictures of the cable are attached, along with my setup. The only thing missing from the pix is the connection of the male USB side of the cable to the iPhone wall charger (the cable is very short to get all in one picture). I lost the official Barrel charger 2 years ago, but the iPhone wall charger DOES charge my Touchpad when in Android mode, so not sure why it won't work for OTG connectivity.
1. I connect the DS4 to the micro-USB controller cable that came with the PS4.
2. I then connect the male USB side of that cable to the female USB of the powered OTG cable.
3. I then connect the micro-USB of the powered cable to the HP Touchpad.
4. I then connect the male USB side to the female iPhone wall charger (I lost the TP Barrel charger a couple of years ago).
And I get nothing. The DS4 seems to have no connectivity with the HP Touchpad using this method.
FYI: Again, I am rooted and running Pac Man Rom 4.4.4RC-1
The strange thing is that when I connect the Touchpad to the iPhone wall charger when it's on Android, it charges! So I don't understand why it's not working when connected to the DS4. Is the official Barrel charger the only one that will work? Do I need to install some app or software to get the DS4 to be recognized via OTG?
Any help you can provide would be greatly appreciated!
Thank you!
Click to expand...
Click to collapse
I will hopefully touch base with you shortly. PM sent.

Small update. Spoke over the phone briefly and he was able to get USB OTG working with a USB mouse (had to unplug/replug OTG cable from TP to have it initialize each time) so it looks like he has the basics for a working OTG setup and an OTG enabled ROM.
Might be the version of ps4 controller he is using or the apk/driver that enables it to work.
Hopefully more to come. Anyone else try this setup before? Chime in.
He is on
[ROM][OFFICIAL][KitKat 4.4.4][TENDERLOIN] PAC-man KK RELEASE [WEEKLY]http://forum.xda-developers.com/showthread.php?t=2779954
[NEW][ALL][PORT][4.0+] PS4 Remote Play for Android (New Thread)
http://forum.xda-developers.com/showthread.php?t=3068225
Sent from my LG G4 on Tapatalk.

An confused update
ConfusedTouchpad said:
Hi ....just an update following my email earlier:
1. I went to a local PC Repair place and they let me use a 5.3V wall charger, to see if some added juice might be enough to get the DS4 recognized by the TP over the OTG cable. Unfortunately, nothing.
2. I went to Gamestop and they let me connect their DS4 to the Touchpad, to see if it would work (using the iPhone wall charger I brought along). Again, nothing.
3. I don't know how this happened, but at one point during the process, the Touchpad turned completely blue and would not respond to anything. I was able to reboot by holding the Vol button down, plus the other 2 buttons. Freaky.
Maybe this info + my earlier email might help you know what's going on? It doesn't seem like this is going to work for me, but you never know.
Thanks!
Click to expand...
Click to collapse
Sent from my LG G4 on Tapatalk.

Another thought on the matter,
Last time I dug into OTG TP setup, there was an issue with either the kernel or the msm chipset that prevented it from using any device directly connected to the OTG cable/port that was asking for more than 100ma or so (ie USB portable drives, CDROM's, etc). You would think this doesn't matter since we are providing power externally separate from the TP but it didn't know that.
The work around was to connect a powered USB hub between the touchpad and the device so that the Touchpad sees the low power Hub on its port, and the hub acts as the middle man supplying the full 500ma out to the device, ie the DualShock4 controller.
Got a powered USB hub handy?
See post 2 for a picture of my hub setup.
(I see I mentioned this in post 1 also)
If u want to see the details, you can get USB port and current draw info from the USB Device Info app or USB Host Diagnostics app linked at the bottom of post 1
Sent from my LG G4 on Tapatalk.

Mr. Grimm....as always, thanks for the info. Other than your responses, it's pretty much crickets in here, eh? (Think everyone else abandoned this thread a long time ago).
I am a little confused about your post below. I did see posts #1 and #2, where it was stated that regular OTG cables wouldn't work for the TP, that you need a powered USB one. That's why I bought and tried a powered cable....in fact, there was a link to it in post #2: "Micro USB Host OTG Cable With USB power".
So if I understand your post below correctly, you're now saying I need something ADDITIONAL (power or an additional cable) on top of the one I just purchased? I'm not sure I understand....I thought I had done what I was supposed to. I connected the USB male part of the cable to the iPhone charger, and also a 5.3V wall charger I tried at a PC Repair store and neither would work. The only thing I've gotten to work, occasionally, is the USB mouse connected to the cable. DS4 not working.
Any help would be appreciated....thanks!
mpgrimm2 said:
Another thought on the matter,
Last time I dug into OTG TP setup, there was an issue with either the kernel or the msm chipset that prevented it from using any device directly connected to the OTG cable/port that was asking for more than 100ma or so (ie USB portable drives, CDROM's, etc). You would think this doesn't matter since we are providing power externally separate from the TP but it didn't know that.
The work around was to connect a powered USB hub between the touchpad and the device so that the Touchpad sees the low power Hub on its port, and the hub acts as the middle man supplying the full 500ma out to the device, ie the DualShock4 controller.
Got a powered USB hub handy?
See post 2 for a picture of my hub setup.
(I see I mentioned this in post 1 also)
If u want to see the details, you can get USB port and current draw info from the USB Device Info app or USB Host Diagnostics app linked at the bottom of post 1
Sent from my LG G4 on Tapatalk.
Click to expand...
Click to collapse

You MAY need the hub if the Ps4 controller indicates it needs more than 100ma on the USB port. Perhaps you can pick one up at Walmart and return it later if it doesn't work.
- Yeah, I don't think many people actually use or have tried OTG with their Touchpad. So there may not be a lot of traffic here.
Most of my OTG info actually originated from my Evo3D threads because it had the same chipset and processor as the Touchpad.
Sent from my LG G4 on Tapatalk.

Thanks. Is 100ma more than the stock TP barrel charger provides? Maybe I should just order one of those off Ebay, if that will provide the power needed, since I need one anyway after losing it. Is the USB hub more powerful than the barrel charger?
Also, adding all these things makes for a really clunky setup and sadly reduces the convenience of OTG connection. I guess I will have to decide if it's worth it.
mpgrimm2 said:
You MAY need the hub if the Ps4 controller indicates it needs more than 100ma on the USB port. Perhaps you can pick one up at Walmart and return it later if it doesn't work.
- Yeah, I don't think many people actually use or have tried OTG with their Touchpad. So there may not be a lot of traffic here.
Most of my OTG info actually originated from my Evo3D threads because it had the same chipset and processor as the Touchpad.
Sent from my LG G4 on Tapatalk.
Click to expand...
Click to collapse

ConfusedTouchpad said:
Thanks. Is 100ma more than the stock TP barrel charger provides? Maybe I should just order one of those off Ebay, if that will provide the power needed, since I need one anyway after losing it. Is the USB hub more powerful than the barrel charger?
Also, adding all these things makes for a really clunky setup and sadly reduces the convenience of OTG connection. I guess I will have to decide if it's worth it.
Click to expand...
Click to collapse
That is not exactly the issue, but you should be using a 2 Amp (2000ma) charger with your Touchpad. 1.8A may work fine though. (Stock is 2.0 or 2.1 Amp I believe)
Regardless of getting 'enough' actual power from a charger to the devices, here is the deal/conversation between the TP's chipset (Host device) and the DS4 controller's usb chipset...
DS4: knock knock. Hi, I'm a device that needs 480ma from your USB port, can you let me in.
TP: From behind the closed door... Sorry, only 100ma or less here.
DS4: But I have my own USB power. [email protected]#%
(TP lets hot little 30ma thumbdrive through, followed but 35ma mouse)
Later... Ds4 comes back with its cute little 75ma Hub friend...
Hub: knock knock. Hi, I'm a device that needs 75ma from your USB port, can you let me and my friends in?
TP: From behind the closed door... Uh, sure you all look like only 100ma or less.
Sent from my LG G4 on Tapatalk.

I don't know many people where I moved to recently but if I can get my hands on a ps4 controller, I can see how thing work on my setup.
Please install those 2 USB info apps I mentioned before, they will help identify what the TP sees on its port:
USB Device Info
USB Host Diagnostics
Sent from my LG G4 on Tapatalk.

[Mod] Apply more power to USB-Ports or add a selfmade powered USB-Hub

ErAzOr2k said:
Does anyone found a way to get 5V directly from the device?
Click to expand...
Click to collapse
Yes, I did. And i prepared a HOW-TO. See snapshots, and pdf in the attachments..
Now the USB have power. I do not get unmounted USB anymore. Maybe you want to try with more current (2A instead of 1 A) but it might damage your USBs.
--update--
Bear in mind that with the current setting, the USBs will have power even when the unit is off. Pendrives and so on will have no problems, as they will shutdown when unmounted by the unit. But if you leave something plugged, it will be consuming battery of your car. It has 2 sides: if you want to charge your phone, you won't need to have the car on. Just leave it there. But, if you forget something there plugged in, in may drain your battery.
If you want a non-permanent USB, you just have to change the pin from which the 12Vin is taken. Instead of taking the Bat(yellow), you must take the ACCin(red).
I hope you like it !!!

typos1 said:
Its great, apart from the fact that it helps only KGL users ! How did you work it all out, so I can try and do it for KLDs and JYs ?
---------- Post added at 05:35 PM ---------- Previous post was at 05:31 PM ----------
Click to expand...
Click to collapse
Thanks. No, it is very general and should be applicable to all units. The main thing is:
- find a source of 12V from the unit (the closest one to the USBs is the harness socket that is on the unit, i.e. the big socket with the fuse). You also need the GN to close the circuit (also on the socket)
- tap this source to the converter to 5V
- tap the 5V to the Vin of USBs. (this wiring is universal for all USBs)
I cannot say all units have the exact wiring of the harness, but it would be very weird if they do not. As a rule of thumb, if the Batt(yellow) and Ground(Black) wires of your unit are in the same positions as mine (see pic below), you can follow the HOW TO and it will work. If the position of these two wires in the socket of your unit is not as mine, then you just have to be careful in figuring out which pin it is in the board (you will see that the pins at the bottom of the board are mirrored with respect to the socket/wire diagram), but the picture I post should be enough for every one to find out their pin.
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dsa8310 said:
I inspected my simple USB hub and I noticed that there is a Schottky diode involved (type SS14) which, I guess, is protecting +5V coming from the USB "in" port from the external +5V voltage.
Unless such diode is present, internally, in the HU, for its (three, in my case) USB ports, there could be a risk involved in powering directly the internal USB ports from an external source.
But I am not an expert here. The low forward voltage of the Schottky diode makes sense, though.
So I would try to identify the internal powering path of the USB ports and insert the Schottky diode there, to be safe.
Click to expand...
Click to collapse
I also thought about that, how to prevent eventual high tension on the Vin of the USB that may burn the plugged drives. At first I wanted to take the current from the fuse, so it is prevented although at 10A.... so in the end quite useless.
But then, I realized that since there's the converter between the 12V and the USB and it cannot output more than 5V 1A, in case of high voltage the converter will cope with it and in the worst case scenario the converter will be burnt. So, I think I am on the safe side here. If one wants to be safer, you could add a fuse between the converter and the USB Vin.
I am not an expert either, so if anyone says this is total bullsh*t, I will try to fix it :silly:

---

devilsoft said:
Yesterday I managed to make DailyRoads Voyager to work. I downloaded the MTC apps uncompiled sources from this forum, and I studied the MTC Travel (Car Record) app sources, to look for clues on settings I need to set to DailyRoads Voyager, and I found them! You need to set in "Settings -> Video" the next values:
- Video Quality: choose Custom
- Video Resolution: choose 640 x 480
- Video Encoder: H.264
- Bitrate: Medium or High
- Frame Rate: High (30fps) (This is what it makes it work finally, as by default is medium selected, and CarRecord has it at 100fps)
- File format: mp4
I also change the settings in File storage, to save the videos on USB Storage (i don't know if this affects the recording), as I have a 120GB SSD.
Hope this will help anybody which has a camera attached to this HU.
Click to expand...
Click to collapse
I didn't look at the front page for a while, but I just had a quick look and noticed that it has a link to this post (#8383). It would be good to include a little bit more information.
The above applies to no-name cams purchased with the HU. They are not high quality and can record only at 640x480 even with DailyRoads Voyager. CarRecorder can only use 640x480 with any camera. However, better quality cameras can record with higher resolutions when used with DailyRoads Voyager or another app. I tested Logitech C930e: very good on 720p, and it can even record with 1080p, but with about half the frame rate of 720p, so 720p seems to be the best option.
------------------------------------------------------------
Also the front page "3G USB Dongle not working properly" has a link to post #7614. I don't see why.
---------- Post added at 12:24 AM ---------- Previous post was at 12:04 AM ----------
dsa8310 said:
Regarding the USB protection with that Schottky diode. Let me put it this way: there are two (ideal) tension generators in parallel; they may be of sensible equal voltage, and their internal impedance is not zero, but very small anyway, and they may be internally protected or NOT.
So, I would protect with the Schottky diode at least the HU USB generator, to be safe, not sorry, in the particular case when the USB device is unplugged (or missing!).
Click to expand...
Click to collapse
I see this solution similar to two batteries connected in parallel. The current will go from one to another, unless they are exactly the same. In which direction? When no USB device is connected, and the original source is protected with a Schottky diode, and the DC-DC regulator probably has something similar, there should be no current in either direction. Why not check it? It's more complex when a USB device is connected. From which source will it draw the power? This depends on the internal impedance of both sources, as well as the impedance of the USB device.
Regardless, it looks like it's working for those who made the modification, so it's probably OK. I'd rather use the DC-DC regulator to power a powered USB hub.

---

TooBusy said:
------------------------------------------------------------
Also the front page "3G USB Dongle not working properly" has a link to post #7614. I don't see why.
Click to expand...
Click to collapse
It used to contain a link to aliexpress with DC-DC converter and a 3G dongle. i think Malaysk must have removed it.

In that case wound´t be better to completely cut the original USB power and use only a 2A new supply for example? the same as disconnecting the internal MIC to the BT.

dsa8310 said:
Right, opening the HU just for the USB, I don't think it's worth doing it, either.
Not to mention that my KLD unit has three USB cables, so identifying the USB circuit is more complicated, behind the HU group of connectors.
While indeed, as you pointed out, the externally powered hub (with same DC-DC adapter, if one must) seems safer, because of the (hopefully) existing Schottky diode.
That being said, if I ever have the opportunity, I will keep the hidden/internal USB powering solution (plus Schottky diode!) in mind.
Click to expand...
Click to collapse
I did that because I have a cable from the back of the unit to the center console. I made a hole in the console where I installed the USB socket. It looks OEM and I like it. But in the previous working conditions, it was useless.
I do not want to have a cable running on the car from the lighter and so on. So, the idea was to fix the USB I already installed on the console. It was easy, and it works.
Probably is not the best thing for everyone, but in my case it worked

patagonia1 said:
In that case wound´t be better to completely cut the original USB power and use only a 2A new supply for example? the same as disconnecting the internal MIC to the BT.
Click to expand...
Click to collapse
I did not think about that. It seems a good idea, so you prevent any overload. I think 2A is too much. AFAIK, USB2 can work from 0.5-1A. USB3 to 1A (also Apple chargers work at 1A). i do not know what would happen with 2A if you do not have a hub which splits your current in 2 or 3 USBs.

patagonia1 said:
In that case wound´t be better to completely cut the original USB power and use only a 2A new supply for example? the same as disconnecting the internal MIC to the BT.
Click to expand...
Click to collapse
That sounds better to me. And you don't need to cut anything. Connect the cable to the unit, the other end USB female connector. Test it and report back. You might get many followers.
---------- Post added at 01:48 AM ---------- Previous post was at 01:46 AM ----------
pakidermo5000 said:
I did not think about that. It seems a good idea, so you prevent any overload. I think 2A is too much. AFAIK, USB2 can work from 0.5-1A. USB3 to 1A (also Apple chargers work at 1A). i do not know what would happen with 2A if you do not have a hub which splits your current in 2 or 3 USBs.
Click to expand...
Click to collapse
2A would be the max. How much is used, depends on how much is needed by connected devices.

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dsa8310 said:
Nice!
Now, let me pour some more water on your solution.
I have the impression that the yellow +12V cable is a permanent/battery +12V.
Click to expand...
Click to collapse
This is something I did not consider, but of which I was aware. The USB led turns off when the HU stops. Either it is only on when the USB is mounted, or the power is always on. I will try today and see if the phone charges all the time. In that case, I would just need to sold it to the ACC. Ultimately I could use the red/ACC to open close a relay that would be connected to the yellow/BAT cable.
dsa8310 said:
While the red/ACC +12V cable might not be suitable as power supply.
Click to expand...
Click to collapse
why ?
dsa8310 said:
Not sure. But take it under consideration.
However, the +12V (hidden) accessory socket is for sure on only when ACC/ignition is on.
So, maybe you'd want to find that feed for your HU USB power (its equivalent may be inside the HU, too?)
And, don't forget about the Schottky diode.
Click to expand...
Click to collapse
I don't exactly know where to put the diode. Should it go between the USBsocket and the internal circuit that powers the USB socket ?
It will require major mods. I maybe would prefer desconnecting the USB somehow and just power it from the loom socket as TooBusy suggested.

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dsa8310 said:
I kind of know that yellow is permanent/battery because installing the new firmware works with the key in the off position.
I think red/ACC may be under-powered? (it just signals the key position?)
Maybe you could find a common internal +5V path for all your USB ports. Insert the Schottky diode (e.g. SS14) on that path (forward position).
Click to expand...
Click to collapse
Well, atm it is not a big deal to have a permanent hot USB. I do not leave anything plugged in the car so as to avoid robberies. I could examine the PCB and see where the 12V pins go, and then tap it frominner parts of the circuit. But, I am not willing to take the HU off again... I have it secured with a screw, so it means I have to remove the glovebox and everything to remove the HU. However, I doubt there will be any problem with my current installation (even without the diode) as the converter will not output more than 5V 1A. If something happens or I modify it, I will let you know.

Best and safest way to power the USB port is to make yourself a powered USB hub.
You either buy a normal Powered USB Hub that has a 5v adapter and and a DC-DC converter from 12v to 5v 3A, to power it or a regular USB Hub non powered and make it powered.
Parts needed:
-regular USB 2.0 Hub
-DC-DC 12v to 5v 3A converter
Converter: http://www.ebay.co.uk/itm/DC-DC-Con...785?pt=LH_DefaultDomain_3&hash=item418e981131
1. Open the USB hub.
2. Locate the GND and VCC cables (+5V) .
3. Cut ONLY the original VCC (+5V ) that comes from the cable that plugs to the unit.
4. To the GND pin, solder the - cable that comes from the converter
5. To the VCC pin, solder the + cable that comes from the converter
6. Assemble back the usb hub.
7. Power the converter. You can take power directly from the main harness of the radio: + from the red cable, and - directly from from the case of the unit or from the black wire.

guys I have been researching this for a while I want to pull the trigger, can you please let me know if what I am planning make sense?
Using the power from the back of the cigaret lighter I get a 12V to feed into this:
http://www.ebay.com/itm/Waterproof-...883693?hash=item58a544fc2d:g:augAAOxy9ERSQ9HE
or
http://www.ebay.com/itm/Professiona...005051?hash=item4d289f383b:g:YggAAOSwaNBUc~f4
from here I will feed the 5v 10amp to the USB hub:
I preffer this:
http://www.ebay.com/itm/Practical-P...029979?hash=item567a7a689b:g:FiwAAOSwu4BVvFWS
or maybe this
http://www.ebay.com/itm/USB-2-0-Hig...844946?hash=item1a0947b892:g:F1MAAOSwHmhV8y71
the USB hub will plug in to the USB port of the Joying head unit,
I will use 24 to 20-AWG USB cables and
draw one to my phone (galaxy s5) by the driver door
and draw 2 more microUSB inside the cabin for passengers and other stuff inside the electronics.
maybe 10amp is over kill but I would rather have more than less.
1) Does anyone see any problem with my plan?
2) Any idea which USB hub and voltage step down I should chose?
I know USB 3 hub is not needed but it does not have any cables and I am hoping it as a bit of better internal compared to the USB 2

Has anyone found a usb hub with car plug adapter plug I can purchase extra? It's all gonna stay in my glove box and have no problem running power cord.. I just can't find one anywhere that tells me the external power plug size so I can buy a car adapter... I keep getting usb camera unplugged
Sent from my Ascend Mate 2 using Tapatalk

superbass311 said:
Has anyone found a usb hub with car plug adapter plug I can purchase extra? It's all gonna stay in my glove box and have no problem running power cord.. I just can't find one anywhere that tells me the external power plug size so I can buy a car adapter... I keep getting usb camera unplugged
Sent from my Ascend Mate 2 using Tapatalk
Click to expand...
Click to collapse
I am just going to open up the hub and solder the feed.

doctorman said:
I am just going to open up the hub and solder the feed.
Click to expand...
Click to collapse
I'm on my way to buy a hub and car adapter I'll let you know the outcome
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---------- Post added at 12:28 PM ---------- Previous post was at 11:40 AM ----------
I need to find our if dash cam and flash drive can work on the same hub...
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