Need a switch that turns on and off at set times? Here is a project by Victor that does exactly that. It’s PIC18F4550 based and uses a DS1307 real time clock chip to keep time. A small 12 volt relay acts as the switch.
This project, like others before, has started out of need: our 30+ year old mechanical timer for the central heater of the house has finally given it up. It would have been faster and cheaper to get a replacement from the local hardware store, but I decided to learn something new and I set out to create a digital version of it.