Drum machine version 3.1 (Circa June 2019)

I haven’t worked on my Drum machine for a long time. So in order that I don’t forget what I did I’m writing it down

I really liked the look of those backlit silicone button sequencers you see all over the place – such as this Adafuit Trellis kit – and wanted to try using them with my drum machine. So I ordered a bunch of them and broke out Eagle CAD

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Measure, print, measure, print again

Just a quick photo of some of the many earlier revisions of the different parts of my quick-release mechanism for the Logitech G920.

Each one is a different revision with slightly adjusted dimensions to get a better fit. Some of the parts were deliberately stopped mid-print once I had enough printed out for the test fit I needed. This saves a lot of time.

At the back are some tests of the threads. I orginally went for a two part ring but simplified it later on to a single part. The threads in Fusion360 need to be manually adjusted to allow a decent amount of clearance. The exact amount depends on your printer and the filiment that you’re using. I used this tutorial as a guide

Logitech G920 quick release

I recently bought myself a Logitech G920 Racing wheel it’s great fun for a bit of Dirt Rally but storing it afterwards is a bit tricky because of it’s akward shape.

So I thought I’d have a go at making a quick release mechanism to allow the wheel to detach from the base unit. At least that way I’d have two slightly smaller things to find a place for rather than one massive, heavy and akwardly shaped one.

What is that and why is it so dusty?
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Drum Machine Version 2.1 (circa June 2018)

I haven’t worked on my Drum machine for a long time. So in order that I don’t forget what I did I’m writing it down. As I write these posts I realise what a lot of dead-ends I have gone down…

This design was created in early 2018 and was intended to be an expanded version of the first PIC32 design with a some specific goals.

  • Create larger device with a less cramped interface than earlier versions
  • Use a better/bigger display for both for better visibility and also to display more information
  • Add a rotary encoder for additional input (I hacked one in as a test on the old design and it was quite useful)
  • Use a “proper” Digital to Analogue Convertor (DAC) in place of Pulse Width Modulation (PWM) plus R/C filter used in the previous design for better quality audio
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ChipStomp – Source code


A quick update to say that I have released version 1.0 of the source code for the ChipStomp.

I’ve spent a fair bit of time making sure that the source is documented in the areas that are less clear and I have removed all redundant/experimental code in an attempt to avoid confusion with things I haven’t finished yet.  That took a lot longer than I would ever have imagined.

You can find the entire project including the Eagle CAD schematics and Layout up on GitHub.

Chipstomp assembly – Analogue side

Fully assembled and working Chipstomp

Fully assembled and working Chipstomp

It’s done.  I’ve assembled the analogue side of the Chipstomp and finally have a fully working device.  There were no errors to fix this time which was a nice surprise.  Just lots of fiddly 0805 surface mount components to place.

I’ve made a quick video of the project to demonstrate what it can do.

Schematics for the Chipstomp

Here are the schematics for the Chipstomp.
I’ve tried to keep as much compatibility with the original DP32 circuit but I have removed superfluous elements such as the on-board potentiometer and one of the user leds. I’ve also added an additional tactile button, the OLED and resistor mixed Stereo to Mono input/outputs.
Other than that it’s essentially just a joining of the ChipKit DP32 with the Stomp Shield.
ChipStomp v1 (PDF 90Kb)Eagle CAD schematic – Zipped (88Kb)

Schematic v1

Chipstomp version 1 schematic PNG (2300×1500px, 80Kb)