Is there any way to connect a USB Host adapter + charge the TF at the same time? I'd like to be able to watch videos (most of which are on my USB HDD) without having to spend hours copying them all to MicroSD just so I can charge the TF (and I use it a lot in my car (while parked, not while driving obviously) and dont want to have to dock the TF to do so (the main reason I use a tablet in the car is there is so little space between me and the steering wheel))
Possibly dissecting a Datacable so it forks the charge into 1 plug and the USB into the other? or wiring in a barrel plug to one of the USB host adapters? (I'm assuming it's not possible to just use a generic USB hub and somehow reverse the power on one of the ports to allow charging...?)
Not sure if his answers your question, but essentially, the pin layout on the cable that connects to the wall charger for the Asus Transformer matches the USB 3.0 spec.
As seen here on Amazon, you'll need a USB 3.0 cable to effectively work as an extension cable for charging via the wall-outlet.
Therefore, by the same logic, if you have a USB 3.0 port on your computer, you'll be able to make use of the extra voltage to do the same thing.
Renarudo said:
Not sure if his answers your question, but essentially, the pin layout on the cable that connects to the wall charger for the Asus Transformer matches the USB 3.0 spec.
As seen here on Amazon, you'll need a USB 3.0 cable to effectively work as an extension cable for charging via the wall-outlet.
Therefore, by the same logic, if you have a USB 3.0 port on your computer, you'll be able to make use of the extra voltage to do the same thing.
Click to expand...
Click to collapse
I don't think the USB 3.0 on a computer will supply more than 5V and 900mA. Not enough to charger the TF.
You best bet is to use a USB 2.0 extension cord, take out the wires that go to pin 1 and pin 4 and connect those wires to a 12V power source.
Absolutely no need to use a USB 3.0 extension cord.
Look here: http://forum.xda-developers.com/showthread.php?t=1087321
To answer OP's question, there's only 1 USB host port on the ASUS Transformer TF101 USB Kit. I don't think that's possible.
Confirm both replies - the Amazon-linked cable does indeed allow an extension of the power delivery from a stock power adapter, but connecting to USB 3.0 port on a PC will not charge the device. Just connected it direct too, not via a hub (even though it is a 3.0 hub - didn't work on that either...)
Suspect custom wiring required, as OP has speculated - anyone?
Can EEE PAD Transformer support Full USB HOST functionality using stock connector provided by ASUS using something like below FEMALE TO FEMALE USB Adaptor ?
http://www.hkcolordigital.com/usb-2.0-a-female-to-usb-2.0-a-female-adapter.html
I know ASUS dock keyboard do have USB port and also, ASUS is selling USB adaptor for around $45, but I do not want to spend that much.
Since ASUS stock connector which is used for charging as well as data transfer from PC support USB functionality, I believe it should be easy to implement.
Any suggestion/solution ?
Thanks
No, it wouldn't work.
http://www.androidtablets.net/forum/asus-tablets/17308-usb-useful-transformer.html
I can't find pinout for ASUS charging connector, but i think it has USB-host pins in it - so you should just solder an USB-female to them in right order.
UPD:
http://www.alwaysinnovating.com/wiki/index.php/40-pin_connector
http://forum.xda-developers.com/archive/index.php/t-1056615.html
this might work. USB OTG is what we looking for
USB Adapter Coupler Type A Female to Female
I have ordered "USB Adapter Coupler Type A Female to Female" from ebay ($3 including shipping):
http://www.ebay.in/itm/120868617077?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649#ht_932wt_1143
Once it reaches to me, I'll try what is possible with it.
I received the "USB Adapter Coupler Type A Female to Female" today and tried to connect USB pen drive and as it was expected, NOTHING HAPPENED.
But, I still think it is possible. I have seen Nexus and Galaxy phones with USB host online.
I think, to be precise, it is not only Female to Female adaptor to be connected to stock connector, but it needs some power (+5v) as well. For this, I think it need USB Y Connector, as in attachment. Below is the link for reference:
http://htc-linux.org/wiki/index.php?title=Msm_Usb_Host
Now, I am thinking to open Female to Female USB connector and solder 2-wire with USB Male connector to it (I have extra USB mouse) for power (+5V & Ground) and try again.
look at last link in my previous reply. There are photos of disassembled host adapter and some schematics-pinouts. TF has USBhost, but it on different pins than usb-slave cable.
Has anyone made an OTG cable for the TFP? I don't like the chunky USB OTG connector and thought an OTG cable would be much better.
Not quite sure what you mean.
The only proper usb connector is a standard type A connector located on the keyboard, it has insufficient pins to implement OTG. The only other usb connectors are the propriety asus ones, one on the tablet and one on the keyboard, the other small connector on the tablet is HDMI output
I have the "chunky" USB OTG connector as well.. I don't think there's a cable though... I looked everywhere on the net
I don't have a dock therefore the only way I can plug a USB flash drive, Keyboard/mouse into the TFT is via the ASUS USB OTG Host adapter View attachment 1384503
I was after something a little slimmer and believe a OTG cable would be ideal - Refer to picture for an example of what I'm referring to View attachment 1384504
Micro USB OTG cables can be used with many phones and tablets sporting a micro USB connector. The TFP obviously doesn't have a micro USB connector therefore I was hoping someone knew how to make an ASUS 40 pin to female Type-A plug which replicates the ASUS USB OTG Host adapter.
Has anyone pulled apart the ASUS USB OTG host apapter? What's inside it?
Hey guys. There are several articles and videos around on how to make your own OTG cable. It essentially involves shorting a single pin. I have no idea if it'll work with a TFP, but I'm going to give it a shot today or tomorrow if I get some time. My plan is to use the normal TFP USB cable, but plug it into a female/female USB gender changer that has been modified to short the pin. I'm almost positive that it'll work on my SGS3, and I don't see why it wouldn't also work for my TFP. I'll report back.
Nevermind. I now see that the TFP USB end has five pins, so they won't match up with the 4-pin female USB port. Oh well...
TFP and OTG
Does anyone know if the OTG will support a USB hub?
gtan2589 said:
Does anyone know if the OTG will support a USB hub?
Click to expand...
Click to collapse
The TFP doesn't have OTG, it's a regular USB host.
So yea, it will support a hub because it's a standard USB device class, with its driver already part of the kernel.
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