HandMuse (hand-held, hand-operated organ)

What is this!?

This is a modular, dual-action, bellows-operated, fully* 3d-printable, handheld, organ, capable of playing up to 13 different notes in any combination! Play single notes or chords, this wondrous instrument can do it all! Pipes are attachable via bayonet connector, and modules all use a common interlocking system so that you too can design your own air-operated noisemakers and attach them to a valve. 

I've configured it to play a full octave plus one: from a middle C4 to C5 including half-tones. For pitch-perfect tonal accuracy, pipe length can be adjusted via screw cap to accurately dial in on a frequency. 

Assembly Guide

Disclaimer: This is complex. Assembly will take several (>5) hours as there is a lot of repetitive, fiddly work (you need to install 13 valve arms and run 13 strings to 13 keys). This v1.0 is definitely not a quick and simple project. In the future, a print-in-place solution would be ideal.

1. Print all the parts :)
2. Assemble ValveBoxes
   1. Place 6x TPU Gaskets in each valvebox with the “lip” facing inwards
   2. Install the input seals. Give them a slight bend beforehand so they press against the gaskets
   3. Install the output seal (6-bladed) and snap fit it into the bottom of the valve. Secure with a dot or two of glue to prevent rotation
3. Assemble the Bellows
   1. Glue link ring into one side of bellow and adapter ring into other side. Make sure that the orientation is correct so that it can screw onto the valvebox
   2. Attach the second bellow and secure it (glue/tape)
   3. Hold off on the Endcaps for now, rotational aligment is important here
4. Assemble the BakersDozenBox
   1. First, connect the 13 Valve Arms to the 13 Valve Seal Feet with a short bit of steel wire. The foot swivel allows for a more airtight and adaptive seal
   2. Again, using small 12mm ish bits of steel wire, pin the arms in place inside the BakersDozenBox
   3. Place the TPU Gaskets
   4. Add rubber bands and tension by adjusting which “spike” they are on or putting knots in rubber bands if they are too long
   5. Install the string-redirector to the internal bayonet connection point 
5. Assemble the KeyBox
   1. Put together the keyboard. Feed a long wire through the hinge holes and insert keys as you go. Pliers recommended
   2. Install the keyboard onto the keybox. A bit of flexing is required, but the bayonet connectors should be rather self-explanatory 
   3. Install pull-rods. Take a long bit of wire (16 cm ish) and feed through hole. Add a bend to the end, feed through rear key-hole, and then bend again downwards to secure it. Repeat 13 times. 
   4. Cut all internal wires to length and bend little hooks on the end so that you can attach string
   5. Attach 13 strings securely to the hooks. I added dabs of hot glue to prevent slippage when not under tension. 
   6. Feed 13 strings through holes in collimator in such a way that the string is as colinear as possible with the pull wire (this will decrease friction). Multiple strings in one hole are ok.
   7. Screw on the Interlock and glue the collimator into place
6. Add adapter box to keybox
   1. Melt in four m4 threaded inserts to keybox top tubes
   2. Run a bead of hot glue as sealant around the tubes before quickly…
   3. Using 4x M4 screws to attach the adapter
7. Connect the BakersDozenBox and Keybox
   1. Twist on. Add rubber bands to both seams to increase twist-on friction and make airtight. 
   2. Feed strings through holes in string redirector and attach to valve arms. I used little wire loops to connect the final couple mm so that I could bend them to decrease/increase string tension. 
   3. For the tubes to fit, you will want to start on one of the rows and begin with the largest tube (C4) and then move along the row until you reach the end. Then, go to the nearest hole on the yet-unused row and continue back towards the start. This makes the largest tubes next to the smallest tubes so that there's space for all of them. 
   4. Test the modules. The simplest way is to put your mouth on where the pipes will go and then suck. When you press the key, you should be able to easily pull air through the hole with your lungs. I found a good ballpark is that if you are able to breathe easily through the hole when the valve is open, the airflow is good. 
8. Attach remainder of modules (ValveBoxes, Bellows). Put rubber bands on seams where parts screwed together for a higher-friction, airtight(er) fit. 
9. Assemble the pipes
   1. This should be rather simple. Screw the tuning caps on to the pipes, and attach the whistles 
10. Tune the pipes
    1. Get an instrument tuner or tuning app on your smartphone
    2. Blow into a pipe and turn the threaded bit on the end until the note is right (a midi/note table may be useful here)
11. Attach the pipes
12. Cross-bar assembly. 
    1. Place the assembled HandMuse onto a table on one of the bellows so it is fully compressed.
    2. screw in the tube-guide and see where the tube lands, install the endcaps there.
    3. Cut the tube to length (one bellow extended, the other compressed)
    4. Insert the tube, and use the printed holes as drill guides into the tube
    5. Place U-shaped metal wire clips to hold the tube in place
13. Enjoy!

Bill Of Materials

3D Printed

Extra Hardware

• 1.2 mm steel wire (Used for hinges, pins, and pull-rods)
• Rubber bands (Used to close valves and act as seal between modules
• Thin plastic wire, non-stretchy. Connects keys to valves
• 15mm aluminum tube. Connects endcaps
• Hot glue / super glue. Secures bellows to PLA parts

Parametric Pipes

The pipes are parametric! With the attached Fusion 360 design, you can craft your own custom pipes by just changing a couple parameters! That said, here are the ones I used:

Printing Tips

• This is a loooooong print. The biggest parts (the BakersDozenBox and KeyBox) took approximately 12 hours each, and all the tubes took quite a while either. It took me about a week of printing to make all the parts, so the total print time is probably between 70 and 100 hours. 
• I designed all the parts to be printable without supports. There are minor exceptions, notably the whistle parts that require supports on the mouth section and the keyboard bracket holders, but otherwise, it should all turn out fine without supports!
• I printed everything on my Prusa I3 MK3, using the standard 0.3mm Draft profile, often with speeds cranked to 160% and beyond to meet my deadlines. Printing slower is advised
• Printing TPU is a bit tricky. Drying beforehand is required to get a proper airtight bellows. I cooked mine in the oven at 50C for 4 hours, and SpiralVase of the bellows turned out perfectly

Known Issues

• Warning: The current bayonet connector on the whistle pieces does NOT fit into the bayonet female piece on the BakersDozenBox since I made a minor change to how the bayonet connector functions. Temporarily, this can be compensated for by replacing the old bayonet adapters by either adjusting the model (see files) or printing as is, snapping off the old bayonets, and printing new ones to glue on. I will update the files soon to fix this. 
• The aluminum tube which connects the bellows endcaps does not quite align with the tube guide hole depending on how you constructed it. Make sure you get the angle right (I didn't so I had to use zip-ties). Also, the bellows buckle (see video) so an additional tube connection at the center point of the bellows would be smart for a v2 design
• Getting the internal string tension done properly so that the key press opens the valve fully is very fiddly. Connecting all the strings is a pain, and it may be necessary to increase key travel by removing the top bit of the keyboard bracket. 
• Bayonet style connectors for pipes are nice, but the long lever arm makes these prone to snapping off. Be careful with them!
• The ValveBox can add weird vibrations sometimes. Make sure all the flaps are tight against the seals so that they don't start to buzz. Maybe add some PLA-comaptible grease to stop vibrations here. 
• One of the white keys is randomly missing a hole? Drill might be necessary.

Acknowledgements

• Michael Krzyzaniak’s Organ Pipe Maker for calculating sizes of the pipes: https://michaelkrzyzaniak.com/organ_pipe_maker/ This was an incredible resource, kudos!
• Jared Butler’s Paper, Highly Compressible Origami Bellows for Microgravity Drilling-Debris Containment (2017) for inspiration and guidance on constructing bellows
• OpenAI’s ChatGPT-4 for providing emotional support and technical advice
• Friends and family for supporting me in this crazy project