After getting my Atari 2600 half-finished masterpiece, Plops!, off my hard drive and onto the intertubes, I realised that I've found an easy way of achieving a nice feeling of closure without ever having to finish any of my half-arsed projects again: just chuck it up on my blog and consider it done!
Accordingly, I present another work-in-progress: an Arduino-based MIDI step sequencer. This was a project I started a few months ago, got really into for an entire weekend, then got bored and left it sitting on top of my speaker to collect dust.
The project started after I dug up my old Dr Sample SP-808 "sampler". This was a bit of a toy that Boss put out in the 90s - not really a sampler, it was meant to be used for - I dunno actually, maybe just sampling some breakbeats to add to a mix or something. It was crap, and I hadn't touched it for 10 years. The thing that made it particularly useless was it's lack of a built-in sequencer of any kind, and although it could be sequenced with something like Ableton Live - there'd be no reason to do that - as Live is about infinity times more powerful on its own. I decided that it might be fun to make a step sequencer for it with my Arduino.
Once MIDI out was working, the only tricky part was multiplexing the input switches. You see, the Arduino comes with a handful of pins for doing input and output - but if you use one pin for every input then you'd quickly run out of inputs. Multiplexing let's you use a few pins to get a lot more inputs and outputs. I used the 4051 multiplexer chip that let's you send HIGH or LOW values to 3 pins, to choose one of 8 inputs/outputs at any given time. Since this was my first go at multiplexing, I thought I'd stick with a simple 8 step sequencer.
The result of my weekend of hacking was a usable sequencer that worked reasonably well. I gave up (and got bored) when it came to using a second multiplexer to show what notes were currently selected. Still, a fun experiment that breathed a lil' bit of life into some old hardware. The project will not be taken any further, however, because I need the breadboard back! But before I pull the plug, here' a demo of it in action...