how to trigger a relay with audio signal (headphone)?

Want output from headphone jack to power relay to turn on power amp

sort by: active | newest | oldest

Simple clap circuit to detect and amplify an audio signal enough to trigger a transistor latch that will trigger the relay. Google Clap Circuit and Transistor latch for schematics.

gramparich (author)  mpilchfamily3 years ago
Excellent idea EXCEPT :
If I turn off audio, it will not turn off power amp............
I need continuous relay hold until audio goes to zero db.
Thanks for suggestion,
gramparich (author)  gramparich3 years ago
My first mistake

The use a transistor switch not a latching switch. The point is you want to take the voltage from the Clap circuit's output and use it to turn on a transistor that will activate the relay for you. When the clap looses audio the transistor looses power and the relay flips off again.

gramparich (author)  mpilchfamily3 years ago
Excellent idea