Boo-It-Yourself

Thursday, September 16, 2010

Halloween Effects SCREAM MACHINE to Scare Innocent People


SCREAM MACHINE
This is one of our “scare tactics” Halloween Effects articles. If you’ve assembled the foot-sensor (light beam) that we discussed, you may want to use this siren based scream machine as the thing to get triggered. The bummer with most store-bought Halloween multimedia stuff is that it lacks real “gusto” when it comes to audio power. Although we are not going to create a typical Halloween sound (like a growl), this will create a sound that will scare most anybody. Halloween illusions are one thing, but you don’t want to make your sounds an illusion! All we need to do is get an alarm siren and a AC to DV power adapter that delivers the very same voltage needed to drive the siren. It’s that simple. You can then wire the siren to the adapter, and plug the adapter into your beam trigger.
Category: Scare-tactic, loud, noisy, tricky, Halloween effect
Skill level: Easy
Time needed: 5 minutes
Truthfully, the only complexity and work in this project is FINDING the two main ingredients either on-line, or perhaps at Radio Shack or Fry’s electronics.
Ingredients:
6-12 volt dc Siren (10 bucks)



AC-to-DC 6 or 9 or 12 volt adapter - 500 ma (7 bucks)



Total Price: $15-25.00

Either visit your local electronics vendor, or simply go to Amazon.com and search for “alarm siren.” You’ll get a lot to choose from. Each siren varies by sound, volume, price, and voltage needed. At the top of my Amazon search I got the $9.99 “Alarm Siren 5" 115 dB 12 VDC.”
I note that I will need a 12 volt power supply to “drive” or “power” this siren.
I next search 12 vdc power supply. I find one for $6.70.
When you finally get your two parts, the only “tricky” part will be to make sure that you connect the positive wire from the power adapter to the positive wire on your siren.
1)   Use wire-cutters or scissors to cut-off the little jack that is at the end of the power adapter.
2)   If the siren has a plug at the end of its wires, snip that off as well.
3)   Strip the plastic/rubber from the ends of the wires to expose the actual wire.
4)   You will twist one wire from the adapter to one wire from the siren.
5)   You must experiment to find out which wire combinations make the siren squawk because you will most likely not know which wires are positive and which are negative. After twisting one set of wires together, just quickly touch the other two wires to see if the siren blasts. If not, switch the wires. Once you have the siren working, just use electrical tape to tape up your exposed wires. Plug your Halloween Noise “scream machine” into a trigger like the previous BLOG light beam foot sensor.





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