Hot/cold air heat exchanger made from soda cans and Pvc pipe. Cheap and easy to build yet very effective.
Long battery life bicycle indicators on single 9 volt battery
Remotely turn your camera left and right.
Use it as an object (beacon) tracking camera mount or selfie stick.
Runs on a 5 volt usb power bank
Did you order a cheap Chinese Arduino copy but it does not work? Keep reading