Forearm rocket launcher

thingiverse

My own 3D printable design of Iron Man's forearm rocket launcher. To build yourself, you will need three servos, an Arduino Nano, and some jumpers, a standard laser diode (optional), a toggle switch, a battery snap, two nails, a drill, super glue or model glue, a bit of aluminum stock, and an inch diameter hole-saw drill bit. The sizes are based on my forearm, so you may need to edit the size of the bracer rings to fit your particular wrist. The Arduino code is the attached Word document; the lift servos used to raise the platform are two separate servo motors with all wires joined to act as one servo, whereas tilt servo is a single servo used to increase the angle of launch to around 30 degrees to ensure the rocket clears the launcher. Servo values may vary depending on how you build it. Wiring is simple: servos and laser all lead to a common ground on the board; I used the other ground for the battery snaps' negative, I used 3V3 to the toggle switch to the laser diode. Lift servos trigger wires lead to D10 and tilt servo leads to D9; all servos power comes from the +5V pin; D2 should go to the switch then to ground. Battery snap positive of course goes to Vin, I used a rechargeable 9V battery but any suitable Arduino power supply should work. Assembly requires some patience: I used Gorilla glue for most parts. First, I used a 1-inch hole saw to cut a circular piece of aluminum out of stock (this is the rocket blast plate). Then, I used the blast plate tool (flat disc with three holes in design) to size where to drill holes; drill two out of the three, make the holes large enough to slip two nails into the holes all the way till the end. Then use the launch guide spacer (two short tubes with an arch in design) to align the nails and glue the nails to the blast plate, these are your launch guides. Glue the blast plate servo mount (somewhat circular piece missing two circular sections with a few weird-looking protrusions) to the back of the blast plate with the nail heads in the center of the missing sections. Next, glue the protruding servo mount to the servo on the opposite side of the laser diode; then glue this assembly to the lift frame (two axles with a stepped-up rear section). Glue the servo to the stepped-up section such that the guide rails are over top of axles. Then slip the movement arms (long rectangular shafts with circles on either ends) onto the axles and slip four of the arm caps (six small circular pieces) over top and glue the caps in place so that the arms move freely. Looking at the assembly from behind, attach the left two arms to the pegs on the side of the mechanical base (flat plate with two risen pegs). You will want to glue the two lift servos so that their shafts are in line with the pegs from the opposite side. Then glue the other two movement arms to the servo shafts; if done right, this should complete the mechanical assembly and you should have a parallelogram-shaped mechanism that moves up and backwards with a rocket guide that tilts up. At this point, if you haven't already wired and coded the Arduino and made sure your mechanism works, now is the time to do so. Then glue the flat base to the largest flat deck of the forearm bracer, such that it surrounds the curved top of the tombstone; then glue the side plates so that they line up with the front plate with the more slanted side facing the back. Finally, glue the wrist brace (long piece with smaller bracer) to the front of the main deck, such that if the bracer is on your forearm the wrist bracer would be on your wrist. This should leave a small gap large enough to slip your battery into while using the gauntlet. The rocket should slip easily onto the launch guides; if it gets caught on the launch guides then do not fire the rocket. I used an Estes A3-4T rocket motor and Estes launch controller, but bear in mind that model rockets are dangerous and that you use them at your own risk. I, the author and designer of this project, have no liability for potential harm brought on by use or construction of this project; I do not condone launching a rocket while wearing the launcher as it is hazardous. Please use rocket motors the way they were designed and specified to be used by the manufacturer. And have fun being Iron Man!