Trigger circuit

[Kevin D]

I want to use a PIR motion detector to trigger a message on a HK828 voice recorder (Silicon Chip Mag Dec 2007). The PIR that I have gives a 2 second closed output via internal relay when it detects movement. First problem is 2 second is too long, the recorder circuit only reacts to a 1 second pulse. Second problem is that multiple movement detection retriggers the internal relay, I need a single shot that will not allow another trigger signal for approximately 60 seconds.

 

[alec_t]

That should be doable. Are the closed relay contacts volts-free at present?

 

[alec_t]

Assuming the relay contacts are volts-free or have one contact grounded then this should do what you want:-
View attachment 69048

 

[Kevin D]

Thank you Alec, I will give it a go.