Using a PIR to turn on a sound module

Hi All,
I have used PIR sensors before but i usually hack one from a cupboard light you can buy.  What I want to do is use a really small (and cheap) board like the trinket (adafruit) and hook it up to the PIR in order to turn on a sound module.  

Does anyone know what board would be best to do this?  All the board will have to do is activate the PIR sensor.  maybe I don't need an actual whole board to get this done?  any clues would be much appreciated.

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FarmerKJS3 years ago

i dont have chematic software so here is the best i can do...

conect the PIR to power and ground then conect the output of the PIR to the play button of a radio shack sound recorder

lonesoulsurfer (author)  FarmerKJS3 years ago
Hey there,
I've tried that before on a project and the PIR sensor only throws out 2-3 volts when activated. I need the sensor to activate the battery's which will be 4.5v


A lot depends on the sound card you want to drive.

lonesoulsurfer (author)  steveastrouk3 years ago

The sound card is one you can use in birthday cards. It's really about the sound card though as I want the to use it as a switch to complete the circuit for the power (4.5v)

Have you tried wiring the sound module as a load on the PIR ? How do you wire them ?

lonesoulsurfer (author)  steveastrouk3 years ago

Not as yet. Still waiting for the sound cards to arrive!

This is how I would be wiring them up:

lonesoulsurfer (author)  lonesoulsurfer3 years ago

So instead of the LED I would use the sound card. I don't believe that this will work as the PIR doesn't release enough power. so even if I used 4 aa batteries (6v) it has a voltage regulator and only releases 3V

In that case, just use a transistor. Put the +ve for the sound card to the battery plus (+ve), put the -ve to the Collector of an NPN transistor, put the base to the PIR, via a 220 Ohm resistor, and put the emitter to the battery (-ve)

lonesoulsurfer (author)  lonesoulsurfer3 years ago

sorry - should have read "its NOT really about the sound card though"

well you could use a relay and do that

lonesoulsurfer (author)  FarmerKJS3 years ago

Yep tried that as well. I found that the PIR didn't open the relay when it was activated. Maybe the relay I was using operated on a too high a voltage (or I could have wired it up wrong!) might give it another try.

Your PIR probably can't drive a big load like a relay either.

lonesoulsurfer (author) 3 years ago

Hi All,

I found this on eBay and will give it a try. The relay runs on 3.3v so it should be fine