Wordbiker

Howdy!

After one of our local LANs, some buddies and I discussed fun mods we could do to our computers. One that stuck was the NoobRocket. Basically, this is a device that is controlled via USB and shoots a Nerf dart at an unsuspecting "noob". We all laughed at the prospect, but my best geek buddy and I have taken the idea up again in the hopes of developing it as a fun toy that has a lot more function than just to merely humiliate (as if that wasn't enough...heh).

For starters, the USB controller drives a pair of servos mounted in brackets to give it pan and tilt. The plan is to mount an infrared webcam to it that will show the target in a window on the screen. The mouse moves the camera and Nerfgun, aiming it for trajectory, and a left click launches it. It gets better...

Other than for night vision capabilities, the infrared webcam paired up with a small infrared laser opens up the opportunity for a couple possible features. As you may know, rangefinders often utilize the IR spectrum, measuring the angle that the beam bounces back to the CCD and calculating the distance by triangulation. "Touchless" thermometers also use either an IR laser diode or LED to measure the beam's reflection to a receiver, and then calculates temperature. Besides those possibilities, one of the more practical reasons we prefer the IR laser is that in certain states, pointing a laser at a human being and causing fear is considered menacing. With a low powered laser (not much over 1mW is required) the classification is lowered as the IR spectrum in such small doses is not considered harmful to the human eye. The telltale red dot is also gone from the "target's" point of view, but can be seen through the IR camera, creating stealth and the appearance of harmlessness to passersby, as well as lowering the chances we'll be sued for encouraging such deviant behavior.

With software, it is possible to operate this gadget over a network, or even from a remote location over the internet. Depending on how our development goes, it could also have features such as autotracking (enabled or disabled through a click for full manual control, using the same logarithm as face-tracking webcams), automatic trajectory compensation (requires the IR rangefinder to calibrate the angle based on the velocity of the Nerf projectile), add-on modules for extra features and upgrades...but really, we just want to get it working first.

OK, that's all fine and dandy techno-geekery, but it'll all seem like a pile of junk if the Nerf gun portion is unreliable. So far, the plan is to use a small pull type solenoid to release a plunger that must be cocked by hand. One shot seems like kind of a bummer, but it does make the overall device lighter, and can still use lower powered servos. To make it more user friendly, the goal is to power it solely from the 5V USB connection, so any power savings are a good thing.

I bought a knockoff Buzz Bee Mech 6 at a local discount store to explore the possibilities of a multi-shot launcher....and found it rather disappointing. First off, the thing is heavy...too heavy for the servos to handle. It appears to use a flywheel that spins constantly (and annoyingly LOUD) to give the darts thrust. There is no tube to guide them, and darts get stuck in it every other shot or so...not that they come out in any way resembling accurately. After that little escapade, I figured that I needed some expert advice on how to make a single-shot, reliable and consistently accurate Nerf launcher...which brought me here.

Several ideas have already been thrown out, such as pneumatic thrust, since the pumping action might cause problems with the fragile electronics and hinges. The air leaking out over time if it were left in a "primed" state also negates the idea of using a compressed air tank or CO2 thrust. This seems to leave me with no choice but a simple spring action. I did take a look at the potential of using a solenoid for thrust, but the power requirements greatly exceed the 500mA of the USB bus, and adding an additional power supply would just add to the overall cost to manufacture it. If it wasn't so impractical, the idea of not having to cock it by hand sure is appealing, and I may try that with another project.

I just wanted to start off this thread with my idea. Rest assured, I will do my best to abide by the forum etiquette and will be studying other threads for ideas on constructing the gun before asking any specific questions. A load of parts is due to arrive tomorrow and I will update this thread with the construction process. Thanks for reading, and please feel free to offer any constructive suggestions you may have.

Wordbiker