Internet connected wearable devices are getting more and more common these days. There are many devices available off-the-shelf right now, but there is something special about being able to imagine and create your own. To accomplish this, I truly think the best platform right now is to use a Pinoccio.
Many people have asked about the instructions and code for the SX-150 mod I did to add MIDI and Audio out, therefore I’m posting the plans for everyone to try. By using the Arduino as the brains of the operation, a lot of other options are available for the mod, really the sky is the limit. If you do any cool hacks to it, by all means, please let me know.
- Gakken SX-150 Analog Synthesizer Kit
- Arduino (This one is the classic, but my favorite ones, are the ones from Modern Device)
- MCP4921 12-bit DAC
- 4N28 Optoisolator
- 1/4” Audio Jack
- DIN 5 Pin Chassis Socket (Female MIDI plug)
- Diode (N4148)
- Resistors(220 ohm, 100k ohm and 3.3k ohm)
- Wire, breadboard (or wherever you wanna do the circuit), soldering stuff and patience.
Connections from the synth
The contact spots shown on the picture refer to the connections on the schematic. Just make sure to get these ones right and that the soldering joints you make are pretty solid.
This part gives you a chance to be creative, so get your tools out and make something cool. For my mod, I used a cigar box, and made holes for all the cables that will get connected with the main circuit. I used epoxy to glue the gakken to the box and it is doing pretty well so far.
Just make sure that you will also be able to change the batteries when planning your holes.
NOTE: It was brought to my attention that the connections P1 and P2 on the Gakken SX-150 are reversed on the schematic above.
Note that there is support on the code for a LED on digital pin 3 that flashes as notes are played. This has not been added on the schematics and it is optional.
If you improve the code, make some other cool mods or have questions, let me know!.
I’m now working on a standalone Arduino based MIDI sequencer on the cheap that can drive this little toy. Updates coming hopefully soon.
The Gakken SX-150 is a really inexpensive analog synth (about $50, now available at the make store). This synth is included on a Japanese magazine (I wouldn’t expect less from them) so that makes it 2*2 times as cool.
Since its release, someone already has created a module to add midi support to it using the atmel attiny2313, but I’ve wanted to use an Arduino board to do it, to keep things easy to prototype and hack.
My implementation uses a single DAC IC chip, the MCP4921, which sells for about 2 bucks from Mouser. The current version uses the Arduino, only to read one byte, as a midi note, from the serial connection and sends that to the SX-150. I could have created the full midi circuit to make it a standalone solution, but that increases the cost and complexity of the physical connections. I’ll probably do that on a later revision.
So, in order to receive midi data, I wrote a small Processing sketch that receives midi, and sends the note information through the serial port to the Arduino.
And.. the whole thing sounds like this:
On the video, I’m using Ableton Live to send midi data to the processing sketch using a Network Midi connection on the Mac. On windows, you should be able to use Midi Yolke to accomplish the same thing. Then, I make sure that the processing sketch receives midi on that same virtual midi connection and sends the data through serial to the arduino. So, depending on your system configuration, you might have to tweak the Processing sketch a little bit to make sure it is reading and writing to the right midi and serial ports.
The flow of data from the sequencer to the synth looks like this:
Ableton Live => Virtual Midi Connection => Processing Sketch => Serial Port =≶ Arduino => DAC => SX-150
And finally, the source code:
Now, hook it up and make some noise!
I just came back from another great High Sierra and saw some excellent bands, but the ones they always stick up are the ones that do something unique. This year, the uniqueness prize (i.e. ultra-super-freak) went to That1Guy.
His main instrument is a home-made invention he calls “The Magic Pipe”, an industrial looking steel pipe contraption that has two ends, where he either plays bass or lead (and he is pretty damn good at both). The 2 strings have an amazingly natural envelope filter like sound, which comes out just as if he was playing a synth bass.
Apart from the strings on the pipe, he has an assortment of midi sensors. There are 13 of them alone on the Magic Pipe and who knows how many more on bass-drum-pedal-driven-cowbells and a single snare that gets no compassion during the live show.
His music is a refreshing mix between crazy funk and industrial, that can easily drive a crowd insane. And, the lyrics are a perfect extension of his instruments: definitely nuts. Don’t believe me? check out this video.
I wrote this little game a couple of months ago and get a kick out of it every I see the main page. It is a clone of the JawBreaker game that comes with PocketPC, but I changed the “balls” with some friend’s heads. If anyone wants their own custom version (with the heads of _your_ friends instead) drop me a line.
You can click on the images to download the game.