Use the Micro Bit and the Inventor’s Kit to build a fan circuit. This circuit serves as radio receiver, and a second Micro Bit as radio transmitter. If the button at the receiver is pressed, the fan of the receiver circuit is switched on. Additionally, the follow-up time is transmitted via radio signal. This means, the fan is automatically switched off after this follow-up time.
These circuits may for example used for ventilation in bathrooms.