A friend told me about a project where kids can only use the computer when they are pedalling the connected fitness bike.
How to do it: Attach a dynamo to the bike, connect it to Arduino which sends signals to computer. On the computer a program checks if the bike is active and if not, turns off display or locks the computer.
For tablets we could write an app that communicates with the RaspberryPi on the bike. We could use the same wireless design for PC.
