:roll: pls. help me make a ckt.-"beam intteruptor" indicator. An alarm should sounds when someone interrupts a more or less 10 meter single IR beam. It's okey if it requires 2 set of module, transmitter and receiver. I just want to be informed if somebody is at the entrance of our gate. Pls. just the simple ckt. not the sophisticatd one. thanks a lot.