Programmable Mechanical Music Box

Hello everyone, so I know I have electric in my name but I just can't help but to be fascinated by mechanical machines and structures. I constantly work on different electronic projects, which is why this is a little more special to me. So without further ado here is my new music machine!

Tools:

• Laser cutter
• Wood glue
• Glue clamps
• Band saw (or other means of cutting wood and metal
• File

Materials:

• A few large 6 mm thick plates (I can't remember how many cause of all the failed prototypes)
• A few large 8-10 mm plates for holding the weel
• 1 x M8 threaded rod
• 50 x M8 washers or nuts (exact amounts depends on your own design)
• 1 x xylophone
• Long low friction lego pegs (32556)

Other requirements:

• Decent 2d design skills
• Shit load of wooden plates
• Skill to operate a laser cutter (or find someone to do it for you)
• patience

I wanted my music wheel to be able to play multiple songs, so I decided to use lego pegs which could be fitted in holes in a rotating wheel which in turn would hit the chosen notes. I designed multiple prototypes before I settled on my final design. All my designs are included in the zip file but a lot of the dimensions are specified for my xylophone, so you will either have to retrofit my files or design your own wheel.

Measure the distance between your notes and space 0.6 mm holes apart so each hole will be positioned perfectly above each corresponding note. After that you need to mass produce these batch after batch until you can fill up the whole surface of the wheel. It is recommended that you produce a few dozen extra ones in case of damage.

(Make sure to cut out a test piece first before you start to mass produce these)

Next you want to cut out enough wheels to provide structural integrity for the surface because the individual holed pieces tend to break easily. I settled on 6 wheels , but depending on your wood type and hole spacing you might need more or less of them.

After this you are halfway done, even though you haven't even glued a single piece. Which is the fun part and will require your patience and focus because you can easily mess this up.

Slide the 6 wheels onto your chosen axis and make sure that they can't wiggle around too much. Space them somewhat evenly and glue the first piece of surface on as displayed on the photo. Do this for all four sides before you start to fill in the rest. Let it dry for the required amount of time and you're done!

For this part of the build I can only really give you design advice for each build will differ depending on your xylophone. But my files will be available of course.

I used an overlay of the designed wheel in inkscape to determine the minimum height, I also made sure that the pegs wouldn't hit the threaded M8 rod when the wheel would spin.

I didn't connect the two side plates with a full bottom plate to save would, but I designed a few bars to maintain structural integrity.

Once you are done with the frame you can loosely assemble the machine but only glue pieces together and use glue clamps to maintain pressure as showed in the photo.

The hammers were a tricky part to figure out, because I wanted them to hover above the the notes so that they wouldn't mute it after hitting it. Unfortunately I ended up ditching that part of the design due to time constraints, but I hope someone out there can do a better job than me. You can use my hammer design and modify it to your own needs. Just make sure they can rotate freely on their axis. You can even use ball bearing if you want to go expensive.

After you've cut all the hammer pieces slide them onto the rod one by one and space them with the appropriate amount of washers so that each hammer will hit it's own note.

I also used a smaller gear to drive the wheel. If I had more time, I would have geared it down even further, but unfortunately time was not on my side. Even so I highly recommend that you do the same otherwise your wheel will spin way to fast and you might even break it.

Done!!! I would say something like "now only your imagination is the limit", or "music knows no boundaries" but you actually don't have a lot of time on the wheel to play with. Besides, you only have one not even full octave to use.

But that didn't stop me from making it anyways so I composed (well programmed) a song all the Dutchies will know from our national december holiday (no not christmas)

so enjoy listening to "Zie ginds komt de stoomboot"

I want to give special thanks to kenyer from the imdib makerspace in the Netherlands where I stored machined and assembled this build :)