SpudFiles

Okay, a little while back, there was a post about a "glade motion sensor mine", well I decided I would make one of my own, out of parts, mine uses 3 9v batteries, two for the solenoid trip, and one for the control circuit. it uses 1 signal diode, a 1kohm resistor, 1 potentiometer (0-100kohms) a NPN transistor, and a photo-resistor, and a 9v relay.... it works when a shadow causes the photo-resistor to open, allowing voltage to pass to the transistor base which then grounds the relay completing the circuit, which complete the 18v triggering circuit, the uses are obvious to any adamant spudder... heres the pics .... oh, and the potentiometer allows adjustment to the level of light/shadow necessary to trigger it

Looks good. Have you got it connected to anything yet, if so show us it.

Thats sweet mate! sounds like you know a liitle about electronics eh?

well, about hooking it up, all my sprinkler valves are modded, so I need to get a new valve that a solenoid will actuate, OHHHH and it only cost me 15$ for all the parts, and I can make 5 more for about 2$ a piece, cause most of the parts came in mulitples of 6... so $25 for 10... and since its made just for this application, Its durable for a lot of shock.... Im planning on using it with a 1"x6" paintball(or flour at home ) loaded barrel, with a 2"x6" chamber. gonna use a laser pointer to increase the amount of light, so that I can create a "trip line" of light...

Reminds me of a similar system used by the Germans in WW2 with wing mounted upward firing cannon on an Me163 rocket fighter that were triggered by the shadow of an enemy aircraft when the plane flew underneath it, have a look.