Hello everyone, I have a project in science and I am puzzled with something. I want to have and IR emitter and an IR detector to act as a burglar alarm that will activate lights and a speaker-like thing. The only problem is that the IR set that I am using opens the circuit until it gets enough IR light then it will close the circuit and allow the charges to activate. However I want the system to activate when the flow of light is stopped. Is there any way to do this? Thank you very much.