Use FreeRTOS (simple, easy, robust, & optimised for the Arduino IDE) to reduce the power required for battery or low power applications.

This tester can be used for NiCd, NiMh, and all flavors of Li-Ion rechargeables.

An Arduino powered floppy disk controller and reader/writer for making and writing disk images from and to old AmigaDOS floppy disks.

Use a 3D printed encoder wheel, LED, and 2 photocells to demonstrate how a quadrature encoder works.

An Arduino interface to communicate with devices using the LANC (Control-L) protocol such as many Sony and Canon cameras/camcorders.

An Arduino-based device that can execute brainfuck code.