Dual analog input with Android and IOIO.  This article will demonstrate a basic dual analog Android USB (or Bluetooth) analog input device.  You guessed it… the Etch-a-Sketch is coming soon!

For additional background information on interfacing Android with IOIO, check out my other introductory tutorials:

Android + IOIO + Simple Digital Output

Android + IOIO + Simple Digital Input

Android + IOIO + Simple Analog Output

Android + IOIO + Simple Analog Input

Background on Android development, IOIO, and electronics:

Meet IOIO

IOIO for Android Beginners Guide

IOIO Wiki

Android Developer’s Guide

Hardware

Parts needed:

  • Android Device (1.6+, 2.1 for Bluetooth)

  • IOIO (available at Sparkfun)

  • 2x Rotary potentiometer

  • Breadboard

  • Power supply

  • Hook-up wire

Assembly

Connect one side of the potentiometer to +3.3V, the opposite side to GND, and the center wiper to the desired analog input pin on the IOIO. The example uses pins 34 and 35, but can be used with other pins that support analog input (pins 31 – 46 on the IOIO). Here is a diagram of the completed circuit (created with Fritzing):

Software

Get the source

With the circuit assembled, the next step is to get the demo application on the Android device. You can either download the pre-built .apk or checkout the source from Github:

git clone git://github.com/mitchtech/android_ioio_dual_analog_input.git

If you are building from source, you will also need to import the IOIO Library project, and optionally the IOIO Bluetooth library projects, both available here:

git clone git://github.com/ytai/ioio.git

Install, connect, profit!

Finally, upload the app to the Android device (or browse to this page on the device and download the apk above). Connect the device to the IOIO, and start up the app.


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