The midi-octopus converts MIDI information into electrical information. The power is turned on to each node, when the corresponding midi note-on message is received. The node stays charged until the midi not-off message is received for that midi note.
Each node is wired to a phono socket on the bottom of the unit (hence the octopus look), which in turn can be wired to pretty much anything you like – solenoids, buzzers, lights etc. The midi-octopus has 64 outs.
Photo: Nikki Pugh
The controller card at the heart of the midi-octopus is designed and built by the amazing Bulgarian company Midi-Boutique. Not only are their products fantastic but they have been really responsive and have helped me when any questions have arisen.
The controller receives midi-in and switches the onboard transistors to allow for a higher power source. I have been using the battery from my rechargeable drill (18V / 2A) but I plan to swap this for a lab bench power supply or car battery in future. If the ultimate power requirement is too high (to get a good whack from a solenoid), I might have to add some higher rated relays.
I found a great supplier of solenoids recently. So I have now built a series of bespoke instruments for the midi-octopus, such as the 16-step solenoid sequencer pictured below.
Photo: Nikki Pugh
The solenoids can be attached to anything. Also, any other types of motors (and various other things) can be attached, so pretty much any mechanical movement can be achieved. Ultimately, the aim is to turn up at a venue in advance and attach them to stuff I find there. For demonstration purposes I have attached them to various objects, using gaffer tape, such as the old ale bottles and poster tube shown below.
Finally, I have wired in some bells and buzzers (below). It was fun going around car boot sales to find old doorbells that nobody wants anymore…yet again, people thought I was a bit potty!
And that is about that. If you have any technical queries not covered here, please get in touch with me!