Automatic key light

This is an automatic night light for your front door where the key is inserted, activated by a proximity detector and of course absence of light to save power, and possibly prevent little kids from playing with it during the day. Just a simple dc light circuit. The switch represents an ambient light sensor or photo cell. The LED that doesn't illuminate represents the IR detector, and the low power red LED represents the IR emitter. It may need adjusted a little (specifically the proximity detector, due to performance and sensitivity), but it should work only when it's dark, and your hand is close enough to it. The IR emitter and detector may need shielded from each other to prevent feedback.

published 9 years ago