
App Inventor (AI2) is an easy way to create Android apps. While originally designed for teaching, it still allows building advanced and complex apps, and was the tool I chose to build a software 2-axis joystick interface for wireless vehicle control.
This article describes the implementation of the joystick as a standalone component that can be integrated into other applications.

In the last few projects I completed, I needed to find a way to process user commands arising from multiple input sources. A simple example would be a clock with tact switches and a Bluetooth interface providing identical functionality from either user input source.