For our music machine we used an ULTimaker 2+ 3d printer and a 100 watt laser cutter to make the different components. The servo gate used was programmed using an Arduino Uno with the tune to Smoke on the Water by Deep Purple because a) it's pretty cool and b) we needed something with only four notes. The instrument used was notes taken from a deconstructed child's xylophone.
Step 1: Create an Archenemies Screw
We modeled a "pig tail" for the screw which was created by wrapping a ramp around a cylinder and cutting out the center with a extrude cut. Each pigtail was about 40 mm tall. We printed as many pigtails as required for the height of our machine, which could be different for you own machine. We recommend keeping the size quite small as to make have a better chance of working on the 3D printer. An Ultimaker 2+ is recommended from our experience.
Get a dowel that fits through the hole created by the extrude (ours was 19 mm diameter). If you have to use a different size dowel or have already printed them out see if you can find a dowel that fits. Put the dowel through the hole of the pigtails slightly turn them and you can slowly screw them on to the dowel. Take a PVC pipe to put around the dowel and cut it to a length of your series of pigtails (our PVC was 60.5 mm to fit around everything). Attach a motor at the top of the dowel by drilling a hole in the top of the dowel and using an adhesive like hot glue or epoxy to attach the two. We used a gear motor from Bird Brain Technologies.
Step 2: The Base
For our base, we used a large flat piece of wood that would be able to fit a return system, our screw, and notes. Ours was about 875 mm by 527 mm. To attach things to the base we used large pieces of wood to act as platforms. These platforms were used to screw through the back and the items were usually attached using some hot glue.
Step 3: Divider
This is the part that went through the most changes through the project since it is such a central part of the project. With a cradle part to fit to the Archimedes screw, and four channels for the ball bearings to roll through. We put servos with their gates pointed down to stop the ball bearings from going through. This is attached to an Arduino that is programmed with the music of choice preferably simple due to the lack of notes. The bottom of the dividers should be covered with a sound dampening material to reduce the noise considerably.
Step 4: Return System
The return system has to have a slight decline to make the ball bearings roll back after hitting the notes. We suggest putting some kind of sound dampener underneath the notes where the ball bearings commonly hit the return. The ball bearings are a little bit random in their landing on the xylophone, so you'll need to make sure all the bearings are landing on the ramp. Walls may be put up on the side of the ramp if the need arises.
Step 5: The Xylophone
The xylophone notes chosen were B, A, G, and E from a children's xylophone, attached to small wooden slats by small screws. There are small pieces of fabric in the shape of washers between the notes and the wood, also taken from the xylophone. The whole thing was positioned below the divider, allowing the ball bearings to simply drop down onto the notes instead of having to follow a track like our original design.