J Beale took a low cost dopler radar and used a Teensy 3.2 and the audio library’s Fast Fourier Transform (FFT) function to improve the sensor range. This is a really cool project. He used the audio library for a non-audio project to make an inexpensive radar module work much better.
More information about the project can be found on this forum thread.
The University of Applied Sciences in Vienna developed the FlipMouse, a replacement for a normal PC mouse to be used by people with motor disabilities. This project really improves PC accessibility to those who need an input device other than a standard keyboard or mouse.
Dave Harper used a trio of Teensy boards to develop a ZigBee based whole-house audio controller. It’s pretty awesome that he was able to emulate an expensive commercial amplifier with this DIY project.
The Teensys emulate one of three MDS-6 audio amplifiers, each of which has 6 source inputs and six stereo zone outputs. The amplifier requires one serial input line and three LED output lines per zone, making the 24 I/O line Teensy a perfect fit.
Vitaly Minko created a tiny One Thumb Keyboard (OTK) using a Teensy++ 2.0.
The OTK provides customizable buttons to create your own useful shortcuts. The tiny form factor allows it to be attached to a bezel of screen for easy access. The OTK is particularly useful for creating shortcut keys for something like photo or video editing software.