[Discussion] Working OTG Devices

mpr90 · Mar 12, 2013

Charging with OTG cable

I too am considering buying a KF2 for use in my car, but need to be able to connect two USB devices (hard drive and DAC) and simultaneously charge the KF2. I saw some posts earlier in this thread about getting OTG mode working with the nightly CM build, but not being able to charge at the same time.

I'm not sure if it is relevant (and I haven't yet bought and experimented with a KF2), but the USB OTG specification allows for five states to be defined by the resistance between the OTG A plug's ID pin and GND. See this Wikipedia article: http://en.wikipedia.org/wiki/USB_On-The-Go#OTG_Micro_Plugs.

I think this is what is being referred to on this thread. There is also a good thread about getting this working on the Galaxy Nexus7.

Unfortunately, it seems from these threads that not all manufacturers fully honour the USB Battery Charging Spec (v1.2). In addition, the infamous "Accessory Charging Adapter" (ACA) is hard to find. Read all about how it is supposed to work here on usb.org (Battery Charging v1.2 Spec and Adopters Agreement).

So, I would guess that first we need to buy/make a USB ACA; second, we need to make sure that the USB hardware supports detection of the ACA; third, we need to make sure that support for this is enabled in the kernel (this link is for the Galaxy S III, but you get the idea).

jnow2 · Mar 30, 2013

nFiniti, what were the volt/amp ratings for the power source that you soldered into your non-powered usb hub? I found a 5v/1.8a power supply that I want to try to fire up USB OTG on my Kindle Fire 2, but since you said that sometimes your unit shows "charging" but most times not, I didn't want to try something that you already said was not charging. I know this defeats the true nature of OTG, but I need a power source so I can watch movies on my Kindle while I am at work.

http://xdaforums.com/showthread.php?t=1589762 For people looking to manufacture their own jig, this link is to an Epic 4g forum on USB OTG. Click on "jig setup" video and see how he made his. The only difference is in the power supply (Epic uses 5 volt, 0.7 amp while Kindle Fire 2 uses 5 volt, 1.8 amp).

willieboya · Mar 31, 2013

jnow2 said:
nFiniti, what were the volt/amp ratings for the power source that you soldered into your non-powered usb hub? I found a 5v/1.8a power supply that I want to try to fire up USB OTG on my Kindle Fire 2, but since you said that sometimes your unit shows "charging" but most times not, I didn't want to try something that you already said was not charging. I know this defeats the true nature of OTG, but I need a power source so I can watch movies on my Kindle while I am at work.

http://xdaforums.com/showthread.php?t=1589762 For people looking to manufacture their own jig, this link is to an Epic 4g forum on USB OTG. Click on "jig setup" video and see how he made his. The only difference is in the power supply (Epic uses 5 volt, 0.7 amp while Kindle Fire 2 uses 5 volt, 1.8 amp).

Why not set up a network and stream your movies to your kindle with xbmc. Thats what I do

Sent from my Amazon Kindle Fire2 using xda app-developers app

jnow2 · Mar 31, 2013

willieboya said:
Why not set up a network and stream your movies to your kindle with xbmc. Thats what I do

Sent from my Amazon Kindle Fire2 using xda app-developers app

I work in a factory that is trying to ban even cell phones because management claims they interfere with machinery. Lots of (less than legal copies) of movies going around on USB flash drives....this would be easier. But thanks for the suggestion!

SilentlyScreaming · Apr 1, 2013

I've been following this thread with interest. Re power supplies and portability, has anyone considered using external battery packs (as in ones with a USB socket to power your phone/mp3 player/anything USB rechargable)? They range in size (and obviously capacity) from credit card width & length (though not thickness

) to proper bricks. Whilst not ever lasting, they do seem to offer a chance to remain vaguely portable, and obviously can be recharged when you get access to a mains point. I ordered a handful of OTG cables when I got my Kindle Fire 2, but will need to wait until I flash a new ROM before delving too deep. That said, none of the cables seem to turn on the activity light of an old 512Mb thumb drive I own, I'll try my wireless trackball receiver sometime.
Anyway, apologies if the battery pack approach has been covered in this thread and I somehow missed it.

nFiniti · Apr 2, 2013

willieboya said:
Why not set up a network and stream your movies to your kindle with xbmc. Thats what I do

Sent from my Amazon Kindle Fire2 using xda app-developers app

Well I have thought of this, Setting up some small "Hotspot" or Wireless Router in my vehicle connected directly to a NAS Device, I would have to figure out how to get internet to that router also. Since I'm using my phone as a hotspot when I'm out and about. I know I can do the same with my phone, Stream from my phone to the tablet but its too much of a hassle. At least for my specific situation.

Plus Movies, and Music isn't my concern. I usually make a playlist of all my favorite songs, and then import them into Advanced WMA Workshop, and I tweek the quality, making all the audio files 96kbs, Stereo, and so fourth dropping the file size down almost half. 800 Songs, 2gb. My main concern is video games and things I can connect. Which is why I need the power and OTG Capabilities I'm working with.

SilentlyScreaming said:
I've been following this thread with interest. Re power supplies and portability, has anyone considered using external battery packs (as in ones with a USB socket to power your phone/mp3 player/anything USB rechargable)? They range in size (and obviously capacity) from credit card width & length (though not thickness ) to proper bricks. Whilst not ever lasting, they do seem to offer a chance to remain vaguely portable, and obviously can be recharged when you get access to a mains point. I ordered a handful of OTG cables when I got my Kindle Fire 2, but will need to wait until I flash a new ROM before delving too deep. That said, none of the cables seem to turn on the activity light of an old 512Mb thumb drive I own, I'll try my wireless trackball receiver sometime.
Anyway, apologies if the battery pack approach has been covered in this thread and I somehow missed it.

Ohh noooo. Thats very good. Esp if people can start developing some sort of wireless Powered OTG Cable. It would help for a true OTG Experience, may be a little bulky compared to just connecting something up to the device through a cable, but we have the short cable anyway. Thats awesome. It shouldn't be too hard either. The power is on the two outer pins (USB Pinouts all over google) and you could easilly take an OTG Cable and hack in a "Wireless Travel Charger" .

I like where thats going. Good Idea's.

nFiniti · Apr 2, 2013

mpr90 said:
I too am considering buying a KF2 for use in my car, but need to be able to connect two USB devices (hard drive and DAC) and simultaneously charge the KF2. I saw some posts earlier in this thread about getting OTG mode working with the nightly CM build, but not being able to charge at the same time.

I'm not sure if it is relevant (and I haven't yet bought and experimented with a KF2), but the USB OTG specification allows for five states to be defined by the resistance between the OTG A plug's ID pin and GND. See this Wikipedia article: http://en.wikipedia.org/wiki/USB_On-The-Go#OTG_Micro_Plugs.

I think this is what is being referred to on this thread. There is also a good thread about getting this working on the Galaxy Nexus7.

Unfortunately, it seems from these threads that not all manufacturers fully honour the USB Battery Charging Spec (v1.2). In addition, the infamous "Accessory Charging Adapter" (ACA) is hard to find. Read all about how it is supposed to work here on usb.org (Battery Charging v1.2 Spec and Adopters Agreement).

So, I would guess that first we need to buy/make a USB ACA; second, we need to make sure that the USB hardware supports detection of the ACA; third, we need to make sure that support for this is enabled in the kernel (this link is for the Galaxy S III, but you get the idea).

jnow2 said:
nFiniti, what were the volt/amp ratings for the power source that you soldered into your non-powered usb hub? I found a 5v/1.8a power supply that I want to try to fire up USB OTG on my Kindle Fire 2, but since you said that sometimes your unit shows "charging" but most times not, I didn't want to try something that you already said was not charging. I know this defeats the true nature of OTG, but I need a power source so I can watch movies on my Kindle while I am at work.

http://xdaforums.com/showthread.php?t=1589762 For people looking to manufacture their own jig, this link is to an Epic 4g forum on USB OTG. Click on "jig setup" video and see how he made his. The only difference is in the power supply (Epic uses 5 volt, 0.7 amp while Kindle Fire 2 uses 5 volt, 1.8 amp).

The new Power Source I'm using is a Verizon Galaxy Tab Car Charger. I chose it because during my Galaxy Tab 7 days, Non of the Chargers I found for it, charged the device, some kept it alive but non fully charged. The Verizon one is a 5v/2a and it is legit! I have successfully connected the Mod Powered OTG 4port hub to the KF2 with Mouse, Keyboard, a pen drive and my Galaxy SII and charged both the phone and tablet with no issues while using the keyboard, mouse and moving files around on the pen drive and internal memory.

However you don't need such power. I've used .5a and they worked to keep the tablet itself alive, 1a successfully charged the device and ran other devices. The 2A powers everything.

jnow2 · Apr 3, 2013

Thanks for the info!

Sent from my SPH-D700 using xda app-developers app

mpr90 · Apr 3, 2013

nFiniti said:
However you don't need such power. I've used .5a and they worked to keep the tablet itself alive, 1a successfully charged the device and ran other devices. The 2A powers everything.

Does this mean you have successfully charged the KF2 whilst running in host mode connected to other USB devices? It looked like from an earlier post, the KF2 would not charge. Did you have to strap the ID pin on the USB micro host connector with a resistor to get this to work?

SilentlyScreaming · Jun 13, 2013

I've been meaning to say, if anyone wants a mains powered USB OTG setup, the following product from DX (DealeXtreme, though I'm sure others stock it), might be of interest - see here for someone confirming the dongle has both a DC input, and comes with a mains adaptor, and here for the actual product details.
Now if it had a standard mini-USB socket for power, it would make things a lot easier, to use a USB battery (see my post above) without soldering, but it is quite cheap, and comes with a built in card reader/USB hub.
FWIW, no affiliate links involved, I've not tried it myself, just thought others might be inspired to experiment. I've still not come off the stock Amazon ROM, so haven't had a chance to fiddle with various devices just yet.

[edit]
Also, I've no idea whether the card reader function will work on a Kindle with the correct sort of JB ROM installed, but at that price, worth a gamble...

naddel81 · Aug 10, 2013

Hi @ all,

I am using the original Amazon-ROM on my kindle fire HD and I'd like to know if the OTG (USB-host) function is dependant on the nightly custom rom.

thx in advance.

flopower1996 · Aug 10, 2013

on cm10.2 i got a wirelles mouse and keyboard working but unforchantly no usb mass storage.

naddel81 · Aug 11, 2013

flopower1996 said:
on cm10.2 i got a wirelles mouse and keyboard working but unforchantly no usb mass storage.

no chance for usb OTG/host on the original rom, right?

flopower1996 · Aug 11, 2013

naddel81 said:
no chance for usb OTG/host on the original rom, right?

I don't know, test it.

Gesendet von meinem Amazon Kindle Fire2 mit Tapatalk 2

naddel81 · Aug 13, 2013

ok, got the OTG adapter here and my kindle fire. what to do now?

smeitmeister · Aug 31, 2013

SilentlyScreaming said:
I've been meaning to say, if anyone wants a mains powered USB OTG setup, the following product from DX (DealeXtreme, though I'm sure others stock it), might be of interest - see here for someone confirming the dongle has both a DC input, and comes with a mains adaptor, and here for the actual product details.
Now if it had a standard mini-USB socket for power, it would make things a lot easier, to use a USB battery (see my post above) without soldering, but it is quite cheap, and comes with a built in card reader/USB hub.
FWIW, no affiliate links involved, I've not tried it myself, just thought others might be inspired to experiment. I've still not come off the stock Amazon ROM, so haven't had a chance to fiddle with various devices just yet.
[edit]
Also, I've no idea whether the card reader function will work on a Kindle with the correct sort of JB ROM installed, but at that price, worth a gamble...

I've tried a similar USB OTG device (http://dx.com/p/cy-gt-037-ri-angled...or-samsung-galaxy-s2-i9100-i9200-black-200091), with my Kindle Fire HD 8.0 on CM10.1 (Hashcode's build), and unfortunately non of my various usb devices (mouse, keyboard, memory stick) was recognized with USB Host Diagnostics.
It might have to do with the kernel in CM10.1 itself, but I'm not sure.

I hope others have more feedback on whether this is kernel or hardware related. Thanks.

xWolf13 · Sep 1, 2013

As said by Hashcode himself. He has disabled USB OTG in the kernel.

Sent from my Carbonized Blaze

smeitmeister · Sep 1, 2013

xWolf13 said:
As said by Hashcode himself. He has disabled USB OTG in the kernel.

As everybody is saying this is common knowledge, I again searched the main thread for Hashcode's "OTG not in kernel" statement.

Indeed, there is a pretty clear reference in http://xdaforums.com/showpost.php?p=41882430&postcount=398 (which says something about my crappy search skills).

4. Power driver is lacking a ton of features in my opinion. It does exactly what it's supposed to and nothing else. It detects a power source and turns on charging. We're missing the entire OTG implementation.

parker.stephens · May 27, 2015

I've tried a mouse, keyboard, and USB Flash Drive. What doesn't work are game controller and external hard drives.

[Discussion] Working OTG Devices

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