Help! Voice recorder tripped by motion detector with time delay

Hi,

I'm an artist, and I'm very new to electronics and would like some help in building/designing a circuit for an artwork.

I want to build a device which records 15 secs or so of human voice, and then plays this recording when motion is detected.

This much is easy enough. However..

I want this circuit, once it has been tripped, to then turn off temporarily for approx 20 mins and then 're-arm' ready for another motion. etc.

I have circuit diagrams for the first part, but have none for the second part, nor any idea how to combine the two if I did. Any help would be greatly appreciated! I plan to build a few of these, so I prefer cheaper parts.

Also, I have been able to find very cheap electronic toys which fulfill the first part of the circuit. Would it be not too difficult to add the timer on to such a circuit, or is it easier starting from scratch and building everything myself?

Cheers!
Richard

SAW 3 DIGITAL VOICE RECORDER | AllElectronics.com $2.00, 30 seconds recording.
**broken link removed** Website with some additional information on re-purposing, and details of the circuit board.

SALE! Quorum A-160 Passive Infrared Detector-The Electronic Goldmine $4.95, see PDF at end of product description for hook up.

20 minute timer... Little much for a 555 chip, maybe somebody else.