Extending the midivox

The arduino never fails to suprise me. Even for someone like me that has close to zilch knowledge about practical electronics, it is so easy to grasp that the possibilities are mind botteling. In a sense, I kind of find the same flexibility I experience developing software. If you got a bit of luck, it’s just a question of assembling the right pieces together and you get an amazing result.

Thinkering with the idea of using the arduino as a microcontroller to deal with inputs and display for a beagleboard synth, I decided to try start by putting together a simple LCD shield from ADAfruit. I still can’t solder for shit but Dorothée‘s really got into it and is very gifted for it.

Apart from being a nice exercise in soldering and getting used to arduino i/o’s, it provides a convinent way to display information (I’m pretty sure the LCD is exactly the same as the shruti-1) and has a ‘D-pad’ + select which – even though they are very poor in the shield itself- make an extremely cheap prototype to test what kind of UI you could develop if you were to use and arduino for control.

Digging through the information about the LCD, I noticed that adafruit was bragging about the shield only taking 2 pins of the arduino (because it uses a dedicated processor that communicates with the arduino using it’s i2c port) and it made me think about what I could do with the other pins. The LCD shield uses two analog pins from the arduino: 4 & 5. So it leaves a lot of room to play with.

The first thing I thought was that I could easily wire 4 additional pots and fiddle around the auduino structure. But then I thought I could dig what pins midivox shield used and discovered that not only it worked on a total different set of pins than the LCD, it still left all of the analog pins completely available.

Even better, when Collin designed the midivox, he added a serie of hole connectors wired to the original arduino pins so that you can hook them up even when the shield is strapped on the arduino.

The result is that it is actually completely straightforward to build a device combining the arduino, a LCD screen, an audio output a MIDI in/out in and 4 pots.

Add a few Lego Brick and you end up with this:

So for about 80 bucks – if you are lazy and by the premade kit – you have a shell that can become

  • A synth
  • A MIDI processor
  • Heck, even an Ableton remote

If you think about making this from scratch, i.e. lying them part on a breadboard instead of using pre-made shield, you can also have a separate MIDI in & out. Also, since the digital pins are unused, it is even thinkable to add a CV cutoff hack to a monotron and have an extremely cheap Digital/Analog powerhouse.

Once connected, all of the part work exactly as originally intended. MIDI works, the LCD works, the pots get read properly. So now it’s just a question of writing software and have fun.

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