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You Rang?
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Discussion Starter #1

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Insane Genius
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what you need is a voltage divider circuit, google for 'voltage divider' and you will find what you want, alternatively you can use a voltage regulator to regulate the 12V down to a lower voltage
 

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Insane Genius
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Ok so the next question is the Voltage Regulator has three terminals can I assume that one is for Voltage in, one it the ground and the other voltage out?
look at the link in my last email, there are a few components you need to add to adjust the voltage.

5VDC regulators are very common, you may be better of using one of those instead of this adjustable one
 

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that looks like the same unit Parrallax and EFX-TEK are selling:

PIR Sensor

EFX-TEK :: PIR Sensor

They work great with a PROP-1!
The voltage specs are different, the Parallax unit isn't spec'd for 12v that the PicoBoo puts out.

P.S. For anyone interested, the pir that Radio Shack sells is actually the Parallax unit. I've been following this thread myself, as I'm in the same boat. Hope Radio Shack will take it back.
 

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To the original question, you need a voltage regulator circuit, they are very simple to create, using an LM317 regulator to bring the input voltage to a safe operation level with the Parralax model.

Google for schematics, they are common!

This 4 pin unit has a cds connection, meaning not only will it operate with motion, but can be hooked up to be reactive in light or dark, depending how you add a cds photo-resistor element.

Since you would be hooking to the picaboo or pickaxe and want 12V operation, you can feed the futurlec models (3 pin here that will work just as well for 50 cents less per unit) without any regulator, it will funtion with voltage in that FULL range.

It doesnt matter that the parralax is a different voltage model than this. BUT you MUST regulate the voltage to 5V as mentioned above - more parts, more work. If you hook the parralax to 12V you will let out the magic smoke, and the PIR will be useless.

Since it uses TTL signal to activate whatever sub routines you want it is a matter of telling the controller how to percieve the TTL.

So don't guess, it is source voltage ground TTL out and CDS, if you hook it up as NO or NC it will not work.
You could hook the TTL to a logic signal controllable relay that has NO or NC contacts.
 

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To get 5V power for the Radio Shack PIR, just use Radio Shack part +5V Fixed-Voltage Regulator 7805. This combination works fine, I'm using them. Despite the documentation, I've seen postings that the PIR only works reliably with 5V. It puts out about a 3.5V signal. Should be fine to trigger ttl logic. As others have said, the 3 pins are Vin, ground, and Vout (5v).

I've used these (without a microcontroller) on my pacman pumpkins project for this year. You can see it at mcgurrin.com/halloween. I have a 9v battery coming into the voltage regulator, and take the output to power the PIR. The PIR output signal (~3.5v) wasn't enough voltage to trigger a 5v reed relay, so I used a transitor to up the output (with the amplified feed coming from the same 5v regulator, so it doesn't exceed 5v). The relay controls a 20 second radio shack digital sound player.

Good luck!
 

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You Rang?
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Discussion Starter #17
I have ordered a couple of the 12v ones and I'm waiting for delivery. I'll post and update after they arrive and I have a chance to test them out.

I may get a radio shack PIR and the fix regulator as a back up, its a lot easier to just go to the shack then sit and wait for parts...

Thanks to all for the input
 
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