76-bit Trombones Led By The Big MIDI File

Inspired by the creative genius of Martin Molin of Wintergatan fame, [iSax] set out to create a robotic MIDI-controlled trombone. It takes years for humans to develop the control and technique required to play the trombone well as the tone produced into the mouthpiece (embouchure) is a tricky combination of air pressure, lip tension, airflow, resonance in the mouth, and other sources of complex pressure.

[iSax] gives a thorough walkthrough of the machine, which is powered by two separate sources of air, one for the position of the slide and the other for producing sound. A potentiometer provides feedback on the position of the slide and a servo controls the flow rate into the silicone resonance chamber. The chamber can be tuned via a stepper motor that applies pressure, slightly altering the chamber’s frequency and pressure. An Arduino with Firmata allows the device to controlled easily from any host computer. A detailed writeup in PDF form is on the Hackday.io project page.

As you can imagine, simulating a human mouth is a daunting task and the number of variables meant that [iSax] ended up with something only vaguely trombone-like. While ultimately it didn’t turn out to be the astounding music machine that [iSax] hoped, it did end up being a fun feat of engineering we can appreciate and admire. Progress towards automatic brass instruments seems to be coming slowly as we saw similar results with this robotic trumpet. Maybe someday we’ll have robot brass sections, but not today.

Thanks [iSax] for sending this one in!

30 thoughts on “76-bit Trombones Led By The Big MIDI File

  1. Nice try but I was expecting more of a musical sound rather than a goose with digestive problems. I know that brass and wind instruments can be automated. I’ve heard musical automata with every sort of instrument.

    1. Sure, It will need more than an arduino and some air tubes and valves to play a decent note out of a trombone. I didn’t listen to the whole video, the sound was terrible.

  2. Sounds a bit like a beginner picking up a trombone for the first time and making some sounds, so to that extent it’s a success. Loads of improvements to make, so it should be interesting to follow. Mechanically I’m a bit worried about the slide actuator flapping the whole thing around, maybe some sort of parallelogram lever could be used instead?

    @Artenz, I hope you wash it out first!

    1. Bagpipes would be easy. Just blow air to fill the bag, something to squeeze the bag, and pads to cover the holes.
      No embouchure issues. Once they figure out how to get a decent tone on the trombone, they will need to figure out how to adjust the tension on the “lips” to get each of the overtone sequences.
      Great first try

  3. Kinda in the Sun Ra sessions vein! Do it with purpose, it will work. Not Prof. Hill’s method, trouble in trombone city!

    It needs a volume of air at a given pressure for more than an instant held under a springy reserve, like an organ reserve in it’s wind supply. An air regulator feeding a tank feeding the “lips” should be a start, the tank needs the diaphragm like our lungs.

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