ITP Notebook [2020 - 2022]

Radial drum machine

May 04, 2021

Intro to Fabrication

This week I attempted to create a physical drum machine/Euclidian sequencer where a spinning mallet hits pegs set at intervals arranged in a circle around the center. The placement of the pegs determines the rhythm.

The concept sketch The concept sketch

The Circuit

To power the device I found a single battery in a holder on the junk shelf. I soldered wires to the leads to connect to my circuit. I then added up a toggle switch in between the battery and the motor.

The salvaged battery holder The salvaged battery holder

The completed circuit The completed circuit

Mounting the Motor

The motor I had on hand was a DAGU hobby gearmotor. I initially wanted to use the spindle because It was easier to attach to a dowel using a friction fit hole, so I started by removing the motor from the gearbox and testing the idea.

Testing the motor Testing the motor

To mount it I thought I could nail the band to two wooden supports. I drilled a hole for the lower gear to fit and nailed two wooden blocks so that the motor fit snugly.

Mounting the motor 1

Mounting the motor 2

This design ultimately failed for two reasons: The motor was spinning too fast and was not that secure. I needed to use the gearbox so I had to modify the design.

Second attempt at mounting the motor Second attempt at mounting the motor

I extended the supports and created a piece that I could attach the motor to. I probably could have opened up the gearbox to remove one side but didn’t want to break it so I drilled a hole where it would go.

The motor in its housing The motor in its housing

The base was short because it needed to be flush against the motor but this meant that when I nailed (yes, nailed) the motor down using holes in the housing, I split the wood and the motor was crooked.

Nailing in the motor Nailing in the motor

The Spinner

The spinner The spinner

I created the spinner with a spring from the junk shelf attached to two parts of a dowel inserted into a square peg. I drilled a hole in the bottom so that it would fit onto the motor (not very securely). I needed to the spring because the rod needed to have some give when it hit the pegs.

The Faceplate

Marking the drill points Marking the drill points

The faceplate consists of 8 holes drilled in a circle around a hole in the center for the motor.

Drilling the center hole Drilling the center hole

After marking the points I drilled them using the drill press.

Drilling the perimeter holes Drilling the perimeter holes

The finished faceplate The finished faceplate

The final touch was a hole for the toggle switch. Once that was done I nailed the faceplate to the base.

Nailing down the faceplate Nailing down the faceplate

Underneath the faceplate Underneath the faceplate

The Result

The final result leaves a lot to be desired — The motor is crooked and the spinner falls of pretty easily. The actual sound is not that impressive although it can be interesting. I would like to have each peg be a different material created like a cymbal where the thing that gets hit is attached to a joint.

The final device The final device