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

Video update on Drum-machine progress

Here’s a video update on where I am with my Drum-machine project. In the past few months I’ve implemented a fair few new features and sorted out some long standing bugs.
Features;

• A new menu mode using the joystick to navigate.
• Added control over the LCD Backlight.
• Added a simple Reverb mode.
• New LCD driver code to render graphics to a buffer and squirt it out to the LCD via 9bit SPI.
• Includes a basic graphics library with some widgets to make creating screens easier.
• Fixed an odd issue with LED’s flashing out of sequence. I had my MAX6957 ports all out or order.
• Added RUN LED flashing to every 4th beat.
• Implemented loading and saving to one of 16 JSON files on the SD card.
• Added a Tuning mode to allow you to individually set the volume and adjust the playback rate of each instrument/sample.

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.

PIC24 drum machine prototype

This is a project I’ve been working on for over a year but haven’t had the time to complete yet. Electronics takes second place to children… 🙂

It’s a mini drum machine modelled on classic machines like the Roland TR808. My version is digital, playing samples rather than analogue and uses a single pic24 to do the work.