Arduino (thus reducing an amazing bit of technology to a USB powered fire hazard). I needed something to fill time while a new one shipped to me. Then it hit me--the Nerf dart, I mean--and I realized what I wanted to build. So, without further ado, I will show you how to build a laser tripwire sentry nerf bomb with a few parts form Radio-Shack and Jameco, and a pet-toy laser pointer. It's also worth pointing out that the tape on the canister you see in the picture has no apparent use. It did in a previus prototype, but you need not add it.. To briefly describe the end result, we will be building an elastic-loaded canister which can fire 4-5 Nerf darts at a person when that person walks through the laser beam. i call it the sentry bomb and it's great for Nerf games and startling you're freinds. Not to mention that with minor modifications you could turn it into a security device, minor modifications like replacing the launcher with an alarm. If you're new to electronics, then the circuit might be tricky for you, but once you understand it, its really quite simple. Have fun building!
To the parts list!
Step 1: Parts list
LM393AN voltage comparotor or similar ----------- Jameco part # 212177 1.90$ for 10
cadmuim sulfide photoresistor ----------Jameco part 202411 1$ each
approximately 2.3 K ohm pot
0.3 K ohm resistor and 0.68 K ohm resistor (actuly I used two to make the 0.68 K ohm one)
a solonoid ---------- Jameco part # 1919191 10$ each
a 2-pole 2-thingy switch. aka one with two separate switches in one and three posts per switch
a cat laser. I got mine at wallgreens for 5$
a soldering board----------Radio Shack, but I don't remember the price
pnp amplification transistor. It doesn't really matter which one I think. i just found one lying around.
solderless breadbord for prototyping----------Radio Shack, butI I don't remember the price
hot glue, solder, elastic, a rubber band, batteries, Nerf darts or similar, 2 small nails, two peices of K'nex or a dowel or somthing, cardboard and wire.
I think that's it. Boy, it didn't seem like that many things when I was rooting though my box-o-junk for parts. Also this parts list is for one sentry bomb, and as we all know, the more the merrier! In case you don't know about Jameco, it's a really good online electronic supply store which can be found here.