Custom 3D Printed MIDI Controller Knobs

Midi Controller Prototype

I’ve been experimenting with building my own MIDI controller. A MIDI (Musical Instrument Digital Interface) controller is a piece of hardware that allows you to control software instruments. My first prototype uses two potentiometers connected to an Arduino Leonardo. To give the prototype a bit more of a realistic feel I decided to make some knobs for the potentiometers.

You can buy knobs or download 3D models but I thought this would be a fun opportunity to practice 3D modelling. I’ve been using Fusion360 and it’s always exciting to start a design from scratch and end up with a physical object.

3D Model

I’m still new to making models so I kept it simple. The knob starts as a cylinder and then you add a hole to fit the shaft of the potentiometer. You could stop at that but I wanted a little more detail. I also rounded the top edge and made a slot in the top so you’ll be able to see the knobs position.

After designing the file I exported it too Cura to prepare it for printing. Cura is a piece of software that maps out the printing path and adjusts all the 3D printer settings. I have my printer, a Monoprice Select Mini, loaded in Cura and I stick to the default print settings for the most part. From Cura you end up with a .gcode file that you can load onto your printer.

Printed Knob

3D printing can take a long time especially on a small and cheap printer. Big objects can take hours. Luckily these knobs are small so they are a nice quick print at about 15 minutes each.

Taped Knob

Once the knobs printed I taped them up to prepare them for painting. You could do this faster with a brush or a white marker but I only had spray paint at home. With tape covering everything except the slot on top I gave them a quick spray and let them dry. It worked well but a bit of paint did leak under the tape and need sanded off. Sanding is a good idea anyway though as the surface won’t be completely smooth from the print.

Finished Knob

The knobs pressure fit over the shaft of the potentiometers and I was happy with how well that worked. They feel professional and have been great for testing my MIDI controller with. While these are great for their purpose if I end up making more there are a couple things I would improve. The side are a bit slippery so some slots or texture on the outside would help with that. They also sit a little high on the potentiometers. It might be worth making the hole deeper and wider at the bottom to fit over the base of the potentiometer.

I’ve uploaded the 3D model so feel free to print your own knobs or modify them however you’d like.

Get the 3D model here: Thingiverse

If you have any comments or questions reach out on twitter!

@iansmith9876