# motion sensor for prop activation



## grim reaper (Aug 18, 2005)

i would like to use a motion sensor to activate my rising skull tombstone. Anyone have any personal experiance or any good how to's to do this ???


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## Otaku (Dec 3, 2004)

Sure do, grim. I built a PIR and timer board system for the $20 Prop Challenge earlier this year. If you don't need a timer you can omit that part of the system. The PIR will send a 2 second, 9VDC pulse when it senses a person. The how-to instructions are here:
http://www.thefrighteners.com/Gary's .htm
Let me know if you have any questions.


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## Torgen (May 25, 2006)

I have a question: What does PIR mean?


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## Brad Green (Jul 29, 2004)

Passive Infra Red sensor. Basically a motion detector eye, just like the ones sold in hardware stores. Their pretty easy to hack for props, you can even send a 110v signal by using a Radio Shack 120v relay. Hacked PIR trips the relay and that operates the prop motor.


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## Torgen (May 25, 2006)

Guess that would be better than buying a bunch of those mats that scream when they're stepped on, and trying to wire them to start the electrical motors, huh?


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## Otaku (Dec 3, 2004)

I use the hacked PIRs for triggering local scares like 20 sec. sound boards, LED eyes, bush shakers etc. At $6 each, the price is hard to beat.


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## roadkill (May 11, 2006)

I have always had a question with it comes to this.

I have seen folks mention the need for a 120V relay when using a PIR to trigger a prop (assuming it's using 120V to begin with).

Why?

Isn't the PIR attached to one or two 120V lights already? Wouldn't that imply there is a relay on the ckt bd to begin with? Why not just use the socket outputs as they are? Couldn't you just use a socket adapter to get your 120V out to a motor or power supply?

BTW - there should be a _SERIOUS_ word of caution concerning running 120 in your haunt. The risks associated are great and, unless you're using GFCI outlets all over, the chance of shocking a patron or actor are greater.

Also to note - Grim is in England where the supplied voltages are 220V @ 50Hz so the timings and voltage solutions will be different for him.


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## Zombie-F (Apr 12, 2004)

That's how I always used the typical hardware store PIRs.


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## Torgen (May 25, 2006)

Another question: Where are these $6 PIRs? 

Edit: I need to attend Haunt Academy or something. Maybe some expert FL haunters can have a weekend lecture/hands-on series?


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## Zombie-F (Apr 12, 2004)

roadkill said:


> I have always had a question with it comes to this.
> 
> I have seen folks mention the need for a 120V relay when using a PIR to trigger a prop (assuming it's using 120V to begin with).


Actually, re-reading your question made me realize the answer. IF you are trying to run a higher current item off of the PIR, a relay MAY be necessary if the item you're running off the PIR draws more current than the PIR is able to provide.


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## Otaku (Dec 3, 2004)

The $6 PIRs are available at Electronic Goldmine, p/n G4567. See my first post in this thread for the hack.

As regards relay voltage and such, this PIR only puts out a 9VDC pulse for 2 seconds when it triggers. It's a stand-alone unit that runs on a 9 volt battery, so the 220 volt system in the UK doesn't apply to the PIR itself. You can attach a 5-9VDC relay (coil voltage) to the output wires to operate a higher voltage prop. For grim's situation, his relay switching capability would need to be able to handle the local power. I would imagine that 220 volt relays are readily available in the UK.


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