Button is an interface for controlling the color and brightness of lights in your home. It turns your Android device into a motion controller, where one dimension is hue and the other is saturation.

The controller itself is independent of any hardware configuration; it sends commands to a server which controls the lights themselves (in my system at home, I use dimsum). This architecture allows you to control your lights from anywhere using the Button controller.

The real-time nature of the controller and the simple-to-understand mapping of motion to color makes it possible to play Button like an instrument. Playing music and making the lights pulse and change color with the beat is especially satisfying.

You can download an APK from Github.

User Interface

The UI of Button is about as simple as it gets: it’s just one big button.

As the user tilts their device to the left and right, the hue shown in the circle changes. Tilting it 45 degrees with the left end down is red; as you tilt it more to the right, it cycles through orange, yellow, green, blue, purple and then back through to red at 45 degrees to the right.

While the user is moving the device, the lights themselves do not change. When the user presses anywhere on the screen, though, the color on the screen gets sent to the lights. The user can hold their finger on the screen as they move the phone, and the lights will respond in real-time.

The circles edge glows when the screen is pressed
The circle’s edge glows when the screen is pressed

Tilting the device away from the user changes the value of the light. When the phone is completely horizontal, the value goes to zero and the lights are off. When the phone is tilted 45 degrees or more in relation to the ground, the lights are at full. Again, the user can hold their finger on the screen and move the phone forwards and backwards to set the brightness of the lights.

The phone being horizontal maps to the lights being off
The phone being horizontal maps to the lights being off

Use it

Because it requires so much configuration outside just acquiring the app, I have not tried to put Button up on the Play Market. You can download an APK from Github. To use Button, you’ll need:

First, wire up your LED strips as described in this fantastic ladyada tutorial and make sure your Arduino is working. Once that’s up, download dimsum and install the RgbSerial sketch included with it to your Arduino.

Now start up your light host (in my case, the Raspberry Pi but any computer with a network connection will do) and fire up dimsum by running:

$ python dimsum.py --dimmer /dev/ttyUSB0

You may need to change ttyUSB0 to match the serial port that your Arduino is running on. You may need to run it as root to allow it to bind to port 80, or set the port to be over 1024 using the --port flag (recommended).

Finally, install the APK, go to the settings and set the address and port of your light host. Make sure that the phone will be able to access this address; if you’re using an external IP, make sure your router is forwarding the correct ports (the correct ports are whatever you set for the HTTP server in addition to port 9000, which is used for the socket connection).

If you don’t want to forward ports, you can use the IP of your host on the LAN, but you won’t be able to control your lights if you aren’t connected to your home wifi.

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