Jim Hawkridge

Electronic Melodeon Project

This page is to document my experiments making a bellows-less electronic melodeon.

When I started thinking about this project I was intending to adapt an existing junk box with my own MIDI electronics. Ostensibly this is to allow me to play in different keys and to practice silently. But really, its just for the fun of the challenge. Either way it soon occurred to me that it would be fun to try to make something small and portable and from there it wasn't much of a leap to think that bellows probably weren't required. When I mentioned this idea over at Melodeon.net someone pointed to some prior art in the form of a bellows-less concertina. This gave me a little bit of confidence that it might actually be playable when complete.

For my first attempt I used a small wooden box found in a charity shop. The two parts of the box were re-arranged to form the bass and treble ends of the instrument. A small pressure sensor is fitted in the joining mechanism between the two halves. The sensor can tell how much pressure is being applied to push the two halves together or pull them apart.

front back

The buttons are standard momentary push buttons purchased from Rapid Electronics. Some additional buttons and LEDs are provided on the back to perform control functions such as key change and voice changes and indicate which settings are in effect. The buttons are somewhat programmable to allow layout changes, key changes, MIDI program changes etc. to be assigned to any button.

The instrument connects to a computer via a USB cable and appears as a MIDI port on the computer. Any MIDI synthesis / sampling software can then be used to produce sound output. Internally a PIC18F4550 Microcontroller reads the buttons presses and pressure information and send the correct MIDI signals to the computer.

So, is it playable? Well sort of...

As can be seen from the video, it is possible to get a tune out of it. But it is rather hard to play for a few reasons:

So I will probably make a mark 2 with better buttons and a different bass position. I think there will be a couple of other changes:

Other things I would like to try:

March 2011

© James Hawkridge 1999-2018