Garage door open alert

[andym1968]

Hi, i would like to design a circuit to show (from inside my house) whether my roller shutter garage door is open. Red LED for open and green for closed. I have a double socket inside the garage near the door to provide power to a plug-in transformer and can drill through to my kitchen reasonably easily. I was thinking doorbell transformer for power? Any advice or help with components appreciated.

Cheers
Andy.

 

[EightyTwo]

A 12V dc power supply would be better. Use a roller shutter door contact (Grade 1 or 2 - you don't need resistors), a transistorised relay and your red and green indicators. Don't use a normal relay - the current and back emf will see off the reed switch in the RSC. Something like a Junior Handy Little Relay Transistorised JHLRT.

Use the RSC to trigger the relay and use the changeover contacts to switch between red and green.