blink1-android

This is a driver library for communicating with blink(1) USB RGB LED notification lights, using the Android USB Host Mode (OTG), available since Android 3.1 and working reliably since Android 4.2.

No root access or special kernel drivers required. The library is 100% Java, using standard Android libraries.

Hardware requirements

To use a blink(1) USB light with an Android device, you will need:

Device running Android 4.2 or later
Device must support USB OTG (check with this app)
USB OTG cable (like this one)
A blink(1) USB LED device

Downloading Library

You can clone the library as a git submodule or download full source code.

Quick Start

1. Add library to your project:

Get library

git clone https://github.com/todbot/blink1-android

Add to your project via "File -> New -> Import Module..."
Set as dependency via "File -> Project Structure... -> Dependencies -> '+' -> Module Dependency"

2. If the app should be notified when a device is attached, add device_filter.xml to your project's res/xml/ directory and configure in your AndroidManifest.xml.

<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>

3. Use it!

Example code snippet:

Open blink(1) device using Blink1Finder:

private static final String ACTION_USB_PERMISSION = "com.thingm.blink1demo.action.USB_PERMISSION";
PendingIntent permissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);

Blink1Finder blink1Finder = new Blink1Finder();
blink1Finder.setContext(this);
blink1Finder.setPermissionIntent(permissionIntent);

Blink1 blink1 = blink1Finder.openFirst();

then use Blink1 API to control the blink(1):

  int r = 255;
  int g = 0;
  int b = 255;
  blink1.fadeToRGB(100, r,g,b ); // 100 msecs to fade to purple
  String serialnumber = blink1.getSerialNumber();

For a simple example, see the Blink1Demo app in the repo.

Development

If you want to work on this app, you'll need to set up your development environment. Beyond installing Android Studio, you will need to to set up ADB to use WiFi instead of USB. (So the USB port is free for blink(1))

Here's one way to do that: https://medium.com/@amanshuraikwar.in/connecting-to-android-device-with-adb-over-wifi-made-a-little-easy-39439d69b86b