Hi, I'm new to Arduino but have used Basic Stamps in the past. I want to activate a 3500V stun gun using either a standard household motion sensor or a Parallax PIR motion sensor. How can this be done? Ultimately I'd like to run multiple guns off of one sensor.
Thanks
You'll be testing this on yourself, first?
HA! no,no,no...It's part of an art installation. don't worry no living beings will be harmed during this production.
http://www.ladyada.net/learn/sensors/pir.html
Just skip to the very bottom of the page which shows the wiring setup and the code.
3.5kV sounds a bit low to me - a taser is more like 50kV.
These: http://arduino-direct.com/sunshop/index.php?l=product_detail&p=43 have a nice 3-pin Gnd-Vcc-Signal connector and free (short) cable all ready to string around..
DISCLAIMER: I mentioned stuff from my own Shop...
Ok, so I've got the PIR sensor hooked up and working to blink an LED, now the trick is bringing the stun gun into the mix...any ideas?
Thanks for the help thus far!
The Stun gun has source voltage of 3.6-7.2V
You could have a servo push the button. Or take the taser apart, remove the button, and figure out some way for the Arduino to connect the two metal contacts of the button. Measure the voltage between the button contacts with a volt meter and use an appropriate transistor (which acts like a lightswitch controlled by the arduino) to connect it.
Uh Oh.. Here I am again with another self-serving suggestion 
Relays are probably the easiest to use for this, although small switching transistors would probably be OK. But I do wonder about the very significant electrical noise these stun guns will produce! What's the plan? They ALL go off at once? Or other patterns?? Optically isolated relays might be really useful.
Search for "relay" here:
http://arduino-direct.com/sunshop/
..You don't have to buy them from me 
One of the reasons I got into this was that I really love scrounging for low-cost parts.
Tell us a little more about your overall plan??
At the moment I just want the Arduino and the gun to communicate. I'll worry about the sequence later. I've brought a 5VDC SPST relay into the scenario, but I think my wiring is wrong.
Inside the gun there is a black box that has 4 wires coming from it. two go to the shocking prongs of the gun and two come out of the back. 1 (red) goes to the button and the other (yellow) goes to the rechargeable battery pack. there are 3 settings for the switch- OFF-LED(flashlight)-STUN.
I've got the (red) going to the NO lead on the relay and the two ends of the coil connected to the anode and pin 13, and the COM to the cathode and GND.
.........
You've got to get at both wires from the switch...
Think about arduino as a brain, desigion maker,
brain must have a sensor to to make a desigion for a problem.
Taser is about 80 kVs.
hi im new to arduino environment and i have a question. is it possible to connect two PIR motion detector to an arduino? it really means a lot if someone responds..