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

Single Inline Breakout for 44pin TQFP package PIC32MX170F256D

Here it is in use with straight pins. Sorry about the crappy photo

Chipstomp assembly – Analogue side

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.

Chipstomp assembly – Digital side

I found some time this weekend to start assembly of my Chipstomp’s.

The digital side of the Chipstomp is assembled and up and running

Chipstomp PCBs have arrived from DirtyPCBs.com

My PCBs arrived from DirtyPCB.com today and they look pretty good! I’m hoping to find a bit of time this weekend to assemble one. Lets hope that I got my footprints right…

ChipStomp version 1 PCBs fresh out of the bag from China.

A higher resolution photo (3069×2456px 1.4Mb)

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)

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

Introducing the ChipStomp : A Digital effects pedal built with a ChipKit DP32 and a Stompshield

Yet another guitar effects pedal

Here’s something I’ve been working on for a while.  It’s a digital guitar effects processor based on a PIC32MX.  

Drum machine progress : From prototype to version 2

I’ve not posted in a long time so here’s a quick update on the progress of my drum machine. It’s come a fair way from the initial prototype documented in this post back in July 2012.

A sneak look at version 2 with a new 32bit PIC and a new larger LCD

Breakout board for Nokia 1202 LCD

I’ve been using Nokia 5110 LCD screens for a while now they’re 84x48px have a built-in back-light and are really easy to use and quite cheap.  Recently though whilst working on my drum machine I found myself wishing for a few more pixels.  I want to show a “pattern view” of 16 tracks with 16 steps plus some additional information and 84×48 was getting too tight.

This isn’t a Nokia1202, this is a Sparkfun Nokia 5110 breakout

Drum Machine prototype – schematic

I found some time to convert my hand drawn notes into a proper Eagle Cad schematic.