I am trying to make a simple alarm system that will alert me if someone has opened a door or window in my house. I have thought about using a control box in the centre of the house that will receive an radio signal from the windows or doors when they have been opened. On the windows and doors I would like a small RF transmitter that only sends a signal when they have been opened, probably via a NC switch.
Are there any simple RF transmitters I can buy that I would not need to program and would just emit a signal when powered?
