usb-serial-for-android

This is a driver library for communication with Arduinos and other USB serial hardware on Android, using the Android USB Host API available on Android 3.1+.

No root access, ADK, or special kernel drivers are required; all drivers are implemented in Java. You get a raw serial port with read(), write(), and other basic functions for use with your own protocols.

• Homepage: https://github.com/mik3y/usb-serial-for-android
• Google group: http://groups.google.com/group/usb-serial-for-android
• Latest release: v0.1.0

Quick Start

1. Link your project to the library.

2. Copy device_filter.xml to your project's res/xml/ directory.

3. Configure your AndroidManifest.xml to notify your app when a device is attached (see Android USB Host documentation for help).

<activity
  android:name="..."
  ...>
<intent-filter>
  <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
</intent-filter>
<meta-data

 android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"

 android:resource="@xml/device_filter" /> </activity>

4. Use it! Example code snippet:

// Find all available drivers from attached devices. UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
 List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
 if (availableDrivers.isEmpty()) {

return; 
}
  // Open a connection to the first available driver. UsbSerialDriver driver = availableDrivers.get(0);
 UsbDeviceConnection connection = manager.openDevice(driver.getDevice());
 if (connection == null) {

// You probably need to call UsbManager.requestPermission(driver.getDevice(), ..)
return; 
}
  // Read some data! Most have just one port (port 0). UsbSerialPort port = driver.getPorts().get(0);
 try {

port.open(connection);

port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);

 byte buffer[] = new byte[16];
int numBytesRead = port.read(buffer, 1000);

Log.d(TAG, "Read " + numBytesRead + " bytes.");
 
}
 catch (IOException e) {

// Deal with error. 
}
 finally {

port.close();
 
}

For a more complete example, see the UsbSerialExamples project in git, which is a simple application for reading and showing serial data.

A simple Arduino application is also available which can be used for testing.

Probing for Unrecognized Devices

Sometimes you may need to do a little extra work to support devices which usb-serial-for-android doesn't [yet] know about -- but which you know to be compatible with one of the built-in drivers. This may be the case for a brand new device or for one using a custom VID/PID pair.

UsbSerialProber is a class to help you find and instantiate compatible UsbSerialDrivers from the tree of connected UsbDevices. Normally, you will use the default prober returned by UsbSerialProber.getDefaultProber(), which uses the built-in list of well-known VIDs and PIDs that are supported by our drivers.

To use your own set of rules, create and use a custom prober:

// Probe for our custom CDC devices, which use VID 0x1234 // and PIDS 0x0001 and 0x0002. ProbeTable customTable = new ProbeTable();
 customTable.addProduct(0x1234, 0x0001, CdcAcmSerialDriver.class);
 customTable.addProduct(0x1234, 0x0002, CdcAcmSerialDriver.class);
  UsbSerialProber prober = new UsbSerialProber(customTable);
 List<UsbSerialDriver> drivers = prober.findAllDrivers(usbManager);
 // ...

Of course, nothing requires you to use UsbSerialProber at all: you can instantiate driver classes directly if you know what you're doing; just supply a compatible UsbDevice.

Compatible Devices

• Serial chips: FT232R, CDC/ACM (eg Arduino Uno) and possibly others. See CompatibleSerialDevices.
• Android phones and tablets: Nexus 7, Motorola Xoom, and many others. See CompatibleAndroidDevices.

Author, License, and Copyright

usb-serial-for-android is written and maintained by mike wakerly.

This library is licensed under LGPL Version 2.1. Please see LICENSE.txt for the complete license.

Copyright 2011-2012, Google Inc. All Rights Reserved.

Portions of this library are based on libftdi ( http://www.intra2net.com/en/developer/libftdi). Please see FtdiSerialDriver.java for more information.

Help & Discussion

For common problems, see the Troubleshooting wiki page.

For other help and discussion, please join our Google Group, usb-serial-for-android.

Are you using the library? Let us know on the group and we'll add your project to ProjectsUsingUsbSerialForAndroid.