Does anyone know how to configure an Android device (tablet) to appear as a USB HID device when connected to a PC?
Is there any other way of getting data from the tablet to the PC (via USB) other than writing it to a file, and have the PC retrieve the (updated) file from the tablet which is acting as a 'mass storage device' for the PC?
Can USB carry a TCP/IP end-end connection?
Using a tablet as a high-end intelligent 'keyboard' or 'mouse' or similar device would be immensely powerful, and open up lots of possibilities. Controlling a model railway layout is the end I have in mind.
Thanks
It's possible to do this using the linux gadget framework http://www.linux-usb.org/gadget/ using a custom composite USB device. The gadget framework is part of the Android kernel source tree by inheritance from Linux.
Unfortunately, Android has its own customizations that restrict the ability to dynamically register new USB gadgets so you will need to patch the kernel source tree for your particular device and add your HID gadget (otherwise you could create a module and load it that way) to the supported Android list.
I have done this before and will update this answer to contain more detail if there is interest. Unfortunately I lost the code so I will have to start from scratch.
If I set up a web server on my phone and enable usb tethering, I can access that server from my PC. If that's not enough for you, this might help: https://market.android.com/details?id=usbwebcam.application&hl=en
I'm running cyanogenmod on a Desire CDMA (BravoC)
Let me know what you find out; it would be pretty handy to use my phone as a USB keyboard in the field. An android server with a PC client is gonna be easiest though.
Have a look at Android Open Accessory Protocol 2.0. This could help you out.
Related
Hello fellow programmers,
I've got a question regarding the realisation of an app which should be able to send AT commands via USB to a connected hardware.
Is it possible to send these commands over USB without root? I would not want to have rooted phones as target market as I want the application to be useable for the average Android platform. Is there any solution out there which you know and can give some links to that?
cheers
herom
If the phones support the optional usb host api then likely yes. You will probably need a USB-OTG style adapter cable which grounds the extra pin to help put the phone in host mode.
If not, no, unless you have one that can be made a usb host via kernel modifications (requiring root, likely kernel reflashing, and possibly a special cable to inject power)
I am a relatively new Android developer but have gotten pretty familiar with the SDK, using LogCat, etc. However, I'm now working on an app (for a Galaxy Tab 7-plus) that utilizes USB Host mode to talk to an external USB device and I've run into an issue.
My question is: What is an ideal environmental setup that will allow me to take advantage of all of the SDK tools (adb, debug, LogCat, DDMS, and so forth) when I am unable to be connected to my PC via USB (since the external USB device my tablet is talking to is using my tab's only USB port)?
Is there an emulator available somewhere (I've searched in vain) that will allow me to simulate USB Host mode using a USB port on my PC?
Do I need to go to some type of on-board logging app?
Is there some kind of 30-pin splitter available so I can connect to both the external device and my PC? (I'm guessing this is impossible, but I'm a hardware idiot... in addition to a run-of-the-mill idiot).
Thanks in advance for your help!
-KR
As I posted in the comments, If the tablet is rooted you can use AdbWireless (Application on the Market)
This can also be done without rooting. Google/Android officially supports this, as described at the bottom of this page:
http://developer.android.com/guide/topics/usb/index.html
But AdbWireless is easier if you are rooted.
Ok, so I have researched this somewhat and am not encouraged, but I'm going to ask anyway, and be specific about what I'm trying to do. Maybe it will help!
I have a custom board with DaVinci processor with USB 2.0 OTG controller on it. I have it configured as a host with an attached hub and various peripherals. This processor runs Monta Vista Linux (MVL) 4.0 with 2.6.18 based kernel. This custom board some video processing and streaming.
I also have a Moto Droid. I can attach the phone as a USB device to my DaVinci system and MVL will enumerate the phone, but obviously doesn't know which driver to use. That I can fix.
So what I would ideally like to do is be able to have a data connection between my board and the phone, and use the phone with a custom app, as a configuration tool (initially). I'm thinking RNDIS would be wonderful, but I don't know if Android supports that on the USB port. Then my custom app would establish a connection over the USB to a server on my custom board.
Can anyone attest to what Android DOES support over USB, besides adb and flash file system?
Any other suggestions are welcome, although please don't tell me "Bluetooth", it doesn't have bandwidth for video, which is a future goal.
Thanks!
For small amounts of data, you could look at Working Android with Arduino, which points at Microbridge (http://code.google.com/p/microbridge/) or you could also look at IOIO (http://ytai-mer.blogspot.com/2011/04/meet-ioio-io-for-android.html).
For things like video, adb port forward (http://developer.android.com/guide/developing/tools/adb.html#forwardports) could be you friend (assuming you have the networking stack on MVL all setup and adb configured). You can basically set up port tunnels for TCP over USB and shift reasonably large amounts of data over the link. One end of the connection (probably the android device) runs a TCP/HTTP server, and the custom board opens connections to communicate. This works reasonably well, you set up a thread running adb devices to detect the plugging in of the Droid device, run adb port forward to set up the port forward, then open your sockets and you're good to go.
Is using 802.11 an option for you on the Davinci board? E.g. either via a Wifi USB dongle or through wired ethernet to an AP? If so, that would seem to be an easier route to communicate with Android than trying to go through USB. Or are your video resolution and compression requirements more than what you'd expect to realistically get through 802.11?
Is it possible to access the USB port on Android phones? (Droid X for example)
Here is my usage case:
Have a USB device attached to the Android phone. The phone listens for data on this USB device. (The USB device is connected to a USB->RS-232 converter that has I/O attached to it)
This would be slick if possible. Does anyone know if this is possible?
Would be slick, yup. Not possible though. There's a feature request for it: http://code.google.com/p/android/issues/detail?id=738
Actually it is possible on a lot of the phones if you are able to install a new kernel with a USB host driver and rig up a custom cabling scheme to provide usb bus power to the device as the phone won't. A few phones even shipped with this capability already live.
I don't know if the Droid X specifically ships with this already, can have it added (if you are able to flash kernels), could have it added but no one has written the host driver yet, or is missing the hardware capability.
You also would need to enable the appropriate usb serial converter device driver (identified by experimenting with the device on a desktop linux box), but that's probably already in the kernel sources and just needs to be selected in the config. You may also need to create a device file for the /dev/ttyUSB0 or whatever and give it permissions appropriate to the application that wants to access it. (This requires root, but if you can reflash the kernel, you can get root)
If you want to pursue this, search the android kernel google group for posts about USB host mode.
One serious downside to putting the USB into host mode is that you loose the adb interface into the phone, which makes working on your projects hard. You'll probably need to either build an adapter for the low voltage debug serial port if there is one (as on G1, mytouch, etc) so you can get a console shell (or just use that instead of USB to talk to your peripheral) or at a minimum set up an ssh and sftp server on the wifi.
Since you want serial anyway, another option people have used is to get a bluetooth-to-serial module from an outfit such as sparkfun.
A bluetooth to serial adapter might solv your problems.
You can find one at https://www.sparkfun.com/products/582. Boards from other companies are also available for example on ebay.
What would be the best way to access the USB as a serial port on an Android device (HTC Magic)?
I am thinking about an OBD-II interface. Can I do this on a standard phone or more likely will I need a modified firmware?
According to this post, Matt Porter presented a review of Android at the Embedded Linux Conference Europe. I mention this mostly because of the example used to describe the current state of Android.
"Just one more practical example: You cannot even plug a USB drive to an android system, since /dev/sd* is not an expected device name in their hardcoded hotplug management.
Executive summary: Android is a screwed, hard-coded, non-portable abomination."
I'm sure someone's working on it, but I'm afraid for now you're out of luck unless you're willing to go low-level and edit the OS.
PSFreedom (project to jailbrack Playstation 3) has list of controllers which support usb host mode which then translate to supported Android devices.
My own expirience is that usb host works on HTC Dream/G1 without problems.
For OBD-II I would suggest bluetooth ODB-II dongle which side-stepps problem with usb host adapter.
Depending on the USB chip in your particular phone, it may be possible to rebuild the kernel to support USB Host mode or USB On-The-Go (Host + Gadget modes) instead of the normal USB Gadget mode. I've found some people speculating that it could be possible on the HTC Dream. Assuming you could reconfigure the USB port in Host mode a USB to serial, ODB-II, or CAN should be doable.
From what I can tell Android is Linux of some sort, to have USB device which would apear as serial port, you should write a driver for that device. I don't know much about OBD-II interface but i am guesing they use some sort of USB driver for windows, same is for android, not mentioning the application to handle the driver.
I don't think the current Android devices can act as a USB host only as a USB device when attached to a host. So using the USB port as a serial port is not likely.
Get a hostmode kernel for your device and you can use python for android and the pyserial library to talk to the serial over USB. I did this with Huawei Ideos U8150 (here is the post) for a loopback test.