I am trying to use the Android USB Host API in order to achieve native USB speeds (on the order of Mbps). I've seen some examples online that use some constants to set up baud rates of 9600. However, I would like to use bulk transfers and control transfers (as necessary, I'm not really sure about how these work, and which constants to use) in order to achieve native USB speeds. Is there any way to do this, and if so, does anyone have some sample code that they would be willing to share? Thanks!
Note: I've also rooted my Android Nexus 7 tablet just in case. I figured that since apps like StickMount need root access, root might be necessary to achieve native USB speeds.
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What classes are available for Android platform to communicate (in/out) with external MIDI device? I have HTC Desire smartphone, it has USB port, I'd assume it is possible to connect it to a MIDI synthesizer, using standard USB cable + [Type A -> Mini A] converter. I'd like to write a MIDI sequencer app that would be able to record MIDI stream from the synthesizer and then play it back later.
Short answer: None. Slightly longer answer: On the HTC Desire there is no built-in support for USB host mode (which you need, since the usb-midi adapter would be the USB client).
(Android 3.1 does have some support for USB Host mode, but that's not available for the HTC Desire)
If you're not afraid of a soldering iron, you could go the midi-over-bluetooth route: http://nettoyeur.noisepages.com/2011/01/midi-over-bluetooth-part-iii-new-hardware/
Much has changed on this front. The following library allows for MIDI i/o with a USB OTG adapter on API 12+:
https://github.com/kshoji/USB-MIDI-Driver
It's far from perfect, and in my testing, pretty crashy, but it should at least be a good starting point for someone looking for the relevant classes.
As #edovino said, you need USB host mode, and then drivers.
If you don't mind rooting around your phone, and the hardware supports it, you do have some options. Check out this link: http://sven.killig.de/android/N1/2.2/usb_host/
This guy was able to get audio, video, keyboard, and some other stuff working. He includes audio/MIDI drivers.
Yes, as pointed above, it is not feasible using the phone because it does not provide USB-host capability. I have been working religiously over the past few months to make an XY-controller for my synthesizer so that I can transmit controller values to use for performances. I reckon, that is what you want to do with additional functionality.
Bluetooth is definitely an option and if you look up for libpd, Peter Brinkmann himself has addressed this issue and acknowledged that Bluetooth dongles for MIDI are not far away.
WiFi is also something one may be willing to look at. Using rtpMIDI, we can create sessions on the PC side of things and use just about any WiFI enabled MIDI device to transmit/receive data. IF you are looking to control software synthesizers using a phone, this seems ideal. TouchDAW and TouchOSC, applications on android, make use of this feature.
With the USB-Android driver, the only problem I see is no support for isochronous transfers using USB host. So, we cannot guarantee latency deterministic. But, considering no other bus accessories attached, the performance seems pretty decent in my tests.
What I want to achieve, is to make a usb device accessible remotely. Next the device will be connected to an android phone which will contact the server through wireless. I would like to avoid writing a complete handler for the transactions. My approach would like to be a bit abstract and as simple as possible I want the usb to be mapped on the network interface, in a way like the phone will actually work as a proxy for the availability of the usb.
And what is your question exactly ?
What kind of devices do you want to connect ?
Ive heart that only android 3.0 can act as usb host ( not sure on this one)
If you can use a industrial device they os supports it http://www.ozdroid.com/#!PRODUCTS
May be some mods can also act as usb hosts
is this the architecture you are trying to achieve ?
[COMPUTER]->(internet/wlan)->[Android]->[USB Keyboard]
There is no abstract/easy way to do this as far as I know the android api does not support anything like that.
May be there are some solutions for this using linux take a look on the android/debian installer ( needs root)
Something like that will probably need at least some native code if not directly a kernel module ...
IF you crate a proxy for a concrete device (for example a keyboard) you could send the keyboard events to a java ( or other) application on the computer but you need usb host support on the device.
From a year ago, Is there a way to communicate with USB devices on Android? this didn't look like a common requirement, but tablets have evolved, and hopefully, the OS has, as well.
I need to operate a simple USB relay card from my Curtis LT8025 tablet, currently running 2.1 patched.
I'm also a newcomer to both Android and java, so relatively clueless!
No need for bi-directional communication, just a simple serial command out to the device.
Any suggestions?
Thanks!
Dave
Sadly, there is currently no standard API to achieve wired communication with Android devices. I was facing a similar issue a while back (see Android: Communicating with a USB device which acts as host ).
I was able to successfully implement the solution provided by CommonsWare. Leave a comment if you need more help regarding this and I can provide details.
Edit (more details) -
Basically, I narrowed down to two possible solutions for this problem:
Modify the Android source itself to include custom drivers for whatever purpose you need and install this in your tablet. Since its mostly based on Linux, if you develop the drivers for Linux, the same can be used in Android with a little modification. This solution is simpler to develop, but not practical commercially if you are not providing the tablet/phone yourself.
Make your USB device act as an host and implement the ADB driver/command-set in your device. When connected, you can issue "adb forward" to forward tcp ports so you can interact with your Android apps and have two way communication between the device and the app.
I used the second method and it works flawlessly. But its only practical if you are making USB host devices. for USB slaves, first method is the only way I recon.
If you are using a serial device and have the ability to talk to it over native serial, you might want to consider IOIO (see http://ytai-mer.blogspot.com/2011/04/meet-ioio-io-for-android.html for more details).
I'm building an Android custom system. I did connect several devices on the USB. I looked to connect a device on the OTG port, the one that usually gets out of a tablet on which you use ADB. I gave up. This is a nightmare. I don't think you can use ADB on the OTG USB that is currently a device and expect to be able to use another device like a USB to serial converter. That means that you loose the whole ADB toolchain for debugging when you want to use the port as a host. On top of that, the USB OTG drivers you have for your tablet was probably not very well tested in host mode since it's not really used that way. So lots of headakes.
The simple way that I found was to use the second USB port on the CPU. This one is a plain HOST port (unfortunately limited to 12 Mbit/s). Unfortunately, I don't know if there are any tablet out there with 2 USB port available from outside (One OTG and one host).
If you get a set-up with two USB port (one HOST) then it's possible to compile as a module (drivername.ko), a usb to serial converter. There are several chipset supported in the kernel source tree and I already used a few of them and it works.
hope this bit of info is helpful.
I've got an application that is written in Java and which talks to a device using virtual serial port (ie a USB CDC ACM device). Currently it runs an a PC (Windows/Linux/Mac OS X),
but it would be a perfect match to be able to port this to a cheap tablet PC to create a stand alone system.
I've been googling for hours now and it seems quite a lot of people are interested in this sort of thin (no surprise there) and some have managed, but I've not found a good match for what I'm looking for or a good place to discuss this.
I'm looking at something like this:
http://www.prlog.org/10776061-101-inch-android-ipad-android-google-mid-tablet-pc.html
I would like to discuss the following:
This says that it supports USB host so it should be doable, eh?
Android is a kind of Linux so I should be able to use a serial dongle there, right?
Has Android got drivers so that I could just plug in a serial port dongle and open it as /dev/tty?
Would the above quoted APAD be usable as a development platform ?
So where would be a best place to discuss this?
br Kusti
To keep this at least partly programming-related: If your application has a GUI, moving to Android is not going to be a load-it-and-go effort. Android has a very different application structure that you're used to and doesn't have Swing (if that's what you're using) or any GUI toolkits other than its own.
On your USB problem: There is support for a few USB-to-RS232C adapters in the stock kernel, but there are a bunch of practical reasons not to use it. Most involve limiting yourself to devices that support host mode, cabling and powering the Android device and the serial adapter. You might be better off using a Bluetooth-to-RS232 adapter on your serial device, which would allow your app to run on a wider variety of devices and gets you the bonus feature of being wireless to put in your marketing material.
I just ported the RXTX library to the Android. Unfortunately I had to fork it to accomodate for different layout of the android projects. More details are here http://v-lad.org/projects/gnu.io.android/
You need to have a device that supports host USB mode. Also the kernel on the device has to support the USB to Serial converter or you have to recompile the kernel yourslef.
OK, so i have seen all the stuff about how acting as a USB host is impossible on vanilla android, but is there anything in the Android API that would allow an app to override the default USB behavior in order to manually control the USB i/o responses, in order to support some other protocol? I have not seen anything that would facilitate this, but is it possible without hacking the kernel?
This seems like the sort of thing which should be relatively easy, but i haven't found anything. Forgive me if i've been googling incorrectly.
I believe that the stock kernel does not include the correct drivers for this. You need to be able to root your device and you need one of the devices capable of acting as a USB host.
See this page, http://sven.killig.de/android/N1/2.2/usb_host/
The linked page had source for the kernel and drivers you'll need ... GOOD LUCK, you'll need it
Last year I worked on an application that had a PC component and a smartphone component, and the two were communicating over a USB connection (using ADB port forwarding and regular sockets). So, if you want to do something like that, I'll show you how I did it, maybe it's helpful.
USB On-The-Go (USB OTG or just OTG) is a specification first used in
late 2001 that allows USB devices, such as tablets or smartphones, to
act as a host
#Wikipedia, If anybody is still looking for it
In order to manage usb traffic your device needs to become a host according to USB specification.