I'm building a talking alarm clock w/2 diff. choices for audio ( through a center off dpdt switch). Each voice recorder has a momentary push button which will be activated by a 5v relay (set n.o & common) when the alarm buzzer sends a PULSING) 3v dc feed to the relay coil when it goes off. The problem is the pulsing makes the voice recorders play more than once a cycle because of the pulsing voltage.I think I need a logic circuit that gets pulsing voltage but will only kick the relay once & then resets. Does anyone know who makes this or how to build it? I assume transistors are used because they haves gates? thanks

 

Lotsa ways to do this. What are the available circuit power voltages? Describe the pulsing buzzer signal in more detail.

ak