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Crank up a Nerf dart blaster to 500 rounds per minute and add a round counter
We made a NERF chaingun fire about as fast as a 7.62mm M60 Machine gun. That's around 500 rounds per minute (RPM). We did two major modifications, increasing the voltage to the firing motor, and adding a round counter and a paint job.
As soon as Eli and I (Aaron) saw the NERF chaingun pop up on tech blogs, we couldn't wait to hack it. We bought 2 for the office as soon as they were available, and as long as we throw the Mana Energy Potion tag on the video, buying guns is totally tax deductible! Cool, huh?
Cranking it Up
The first modification was to increase the voltage to the motor. More voltage with available amperage means a faster spinning motor. Faster motor means more rounds down range, or into Eli's face, as the case may be.
The Nerf Vulcan EBF-25 starts with a requirement for 6 D-Cell batteries. That's an expensive number of big cells. I thought they were all wired in series to yield about 9 volts, but I later found out that they were wired with two parallel groups of 3 in series. That means the Nerf gun runs at about 4.5 volts. (Update: Thanks to Nick, I checked the original pack with a multimeter and, sure enough, it is 9v. 6 D-Cells in series it is. Thanks Nick!)
We ordered these cheap battery packs off of Amazon . I thought that two 9.6v battery packs would get us a lot more out of the gun without melting it.
Things you need for this step:
•1 x Nerf Vulcan EBF-25 ($50)
•2 x 9.6v battery packs
•2 x 9.6v battery pack connectors (RadioShack)
•2 x Alligator clips
•3 x Wire nuts
•1 x Ballpoint pen
•1 x Chopstick
•1 x Mana Energy Potion
•1 x A hint of stupidity
To connect the battery packs to the gun, we actually had to make a little tool. The power terminals are too deep inside the gun to clip on the alligator clips, so I took apart a ball point pen, slit up the side, put a compressed alligator clip in it with the lead hanging out the slit. I put the alligator clip on the battery terminal and then pushed a tie-wrap (or chopstick) through the back of the pen, slipping the alligator clip out and hooking it on to the power terminals. it worked like a charm.
Hook the battery packs together like in the photo. *WARNING: If you hook this up wrong, you could dead short the battery packs together which could make them explode or do other scary/injurious things.* Hook the negative power terminal from the gun to the black lead on pack A, hook the red lead from pack A to the black lead on pack B, and then hook the red lead from pack B to the positive power terminal on the Nerf gun. Voila. It's done. Now separate the alligator clips with a piece of cardboard to keep them from shorting. Stuff everything back into the gun and close the door. Now you have a 500 round per minute cube warfare weapon of mass destruction.
5 darts in the air simultaneously! And yes, that's a Donkey Kong machine we got off Craigslist
Adding a Round Counter
The second major mod was an LED round counter like the one in Aliens or on pretty much every FPS gun out there, as well as a cool paint job.
•1 x LED counter from QKit ($18)
•1 x Lever/Roller microswitch
•1 x LED
•3 x Momentary pushbutton switches
•1 x 12v miniature battery
•1 x Coil of wire
•1 x Various paints
It took me about a half hour to solder together the counter from QKit. A big part of that time was trying to figure out which resistors were which, so make sure you have a guide before you start. Instead of using the microswitches from QKit, I soldered leads from their locations on the circuit board to pushbutton switches mounted on the gun. The three switches are Set, Program, and Reset. The LED comes on when you run out of ammo, which was accomplished by just hooking it to the "out" pin on the counter.
We took the top of the ammo box off and used it to house the counter. Jon Dremeled the spot for the LED counter out. We Dremeled part of the chain-gripping assembly to mount the roller switch. This way the links would hit the switch each time the belt advanced. The leads from that switch go to the counter through holes Dremeled in the top of the chain guide.
Thanks to his experience painting figurines, Jon did an awesome job of painting the gun to look like it was a well-used gun from the future. This was accomplished with a base matte black primer coat, and then metallic silver paints mixed with various levels of black to give variety to the metal pieces. Then Jon went in and put metallic silver on black parts that would show wear, like behind the charging bolt or near buttons. He said it wasn't that hard, but I was pretty impressed.
The third mod has been done a million times before, but it's worth mentioning. We just clipped two of the 25 round belts together to make a 50 round belt. You can see me wearing this stylish bandolier in parts of the video, and then we actually used the 50 round belt in the drive-by shooting. As a side note, strangers got into the elevator with us when we were videotaping and it was very awkward. Bandolier? Not so stylish.
Shooting Your Coworker
The total cost on this hack was about $79
1) We're not affiliated with Nerf, Radio Shack, QKits, Dremel, or anything else you saw us use to build this. Mana Energy Potion is the exception, because that's who we are.
2) There's a very real danger to doing this mod. Dead-shorting battery packs like these can cause them to explode and injure you. Nerf even has a "Do not modify this dart blaster" warning on the gun itself. That's where we used the Dremel to cut out the panel for the LED counter.
3) You will probably ruin your Nerf dart blaster. We could smell the motor burning when we fired it with 4x the voltage. Eventually, the motor coil will probably melt. Also, the gears will probably strip out.
4) Don't paint over your orange tip. That's illegal as far as we know. Fortunately, the orange tip is separate, so you can paint your gun and then attach the orange tip.