Hammond-Inspired Tonewheel Organ Robot

Stepper-Driven, MIDI-Controlled, Tonewheel Robot made with laser cut sheet metal tonewheels and custom-wound pickups

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This is a project I've been working on for the last couple of months. The idea behind it is to emulate some of the construction of Hammond organ tone generators. I've got a build video below, and will be posting some notes, images, and putting together a build log. Stay tuned for updates!


Basic idea of this project is to use some of the design elements of Hammond (and other) tonewheel organs to make a MIDI-Controlled robot.  The design currently includes 3d printed gears, some flat-pattern acrylic, custom pickups, and sheet metal tonewheels.

Check out the build video for more details!


1. Pickups: Made with a 3d printed bobbin and wound using my pickup winder project

2. 3D Printed Components - Gears, Brackets, Motor Mount

3. Polepieces - Cut from Mild Steel Rods

4. Laser Cut Chassis


- 3D printed PETG motor mount, High Torque NEMA23 Stepper Motor, and a set of gears makes up a 1:8 gearbox.

Drive section is composed of more gears + 8mm rod stock and tonewheels

Files for 3d Printing the Pickup Bobbin

x-zip-compressed - 70.24 kB - 02/11/2021 at 14:45


  • 1 × NEMA 23 Stepper Motor
  • 1 × Pololu High Power Stepper Driver 36v4 #3730
  • 1 × Arduino Due
  • 1 × Custom Single-Pole Pickups
  • 5 × Custom Laser Cut Parts

View all 6 components

View project log

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Zero1Tango wrote 03/03/2021 at 21:26 point

Great project! Very polished video, too!

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TheMixedSignal wrote 03/07/2021 at 22:01 point

Much appreciated! Hoping to work out some of the kinks here pretty soon, too :)

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Dan Maloney wrote 02/09/2021 at 22:13 point

Nice job, I actually just wrote this up for the blog. I had no idea that's how Hammond organs worked, but it makes so much sense now. Thanks for sharing!

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TheMixedSignal wrote 02/09/2021 at 22:20 point

Awesome! Thanks for the writeup!!!  Yeah I had sort of a rough idea about how the tonewheels worked based on a wikipedia rabbithole I fell down a few years ago, but there's a lot of nuance there on how the different tones are made/mixed in that I've since checked out, and I thought it was just too cool not to try out on my own.  Thanks for checking this out and writing it up - can't wait to read it!

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