• I’m planning a Wii Nunchuk extension board for my next project. It sounds wacky, but if you look at the amount of sensors / controllers this thing packs for $10, it’s insane. What the Nunchuk can do:

    • 2 buttons
    • X/Y analog joystick
    • X/Y/Z accelerometer

    The preferred communication protocol I am using on my next project is SPI. Without entering in details, it is broken down into more “modular” components communicating through SPI, which is much more generic than the 6 PWM control signals/shift register output/UART TX interfaces on the Shruthi. However, it would cost only a few square inches of PCB to add room for a MIDI socket to the Nunchuk board to turn it into an independent MIDI event generator.

    My questions are:

    • would you be interested in a Nunchuk MIDI controller as a standalone product?
    • how would you play it? Using the analog joystick as a X/Y controller is obvious. Would you use the buttons to trigger notes? Latched mode (one press for note on, one press for note off) or continuous (note on on press, note off on release)? What about the accelerometer: controller or note trigger? Any ideas of other interaction methods for playing melodies?

  • Oh I would totally be interested! But you’ve probably guessed that after my post on controllers.
    Well the accelerometer could be interesting to be used to add gestural control to synths, one obvious use could be controlling parameters like cutoff or PWM/FM strenght through the accelerometer
    A more complex (for the performer) use could be to track pitch with the device… but I don’t know how well that works with the accelerometer…
    Still it could be fun to use as a kind of air-theremin, where you trigger a note with the button, control pitch with potition and control some more parameters with the joystick… or maybe use two of those to have both pitch and a CC value you can control with independent hands.
    I can imagine this could be real fun!

  • Yeah these things do pack a lot of useful technology into something so small and cheap..
    I was recently watching a vid were some chap was gutting one to use it’s key parts in an RC drone. The accelerometers are good for the auto stabilisation hoopla.

    Back to midi however.. Is a bespoke hardware mod/device really needed for Wii/Nunchuk midi control? Im thinking not.. Simply because it is already very cheap and easy to use a Wii controller, as a midi controller. I’ve been doing just that for a couple of years now.

    The regular Wii controller has bluetooth, obviously.. And these days many computers have it included also (if not, then it is cheap and simple to add). So then all you need is software to translate the wii movements and buttons, into midi messages.

    Macs have Osculator (which is great!)
    And PC users have GlovePie, which does a similar thing.

    Im guessing you plan to do a computer free/standalone version though? But when it is already this cheap and easy to do (and we all have computers) im not sure how justified it would be to do it standalone..

  • My next project is going to have a Nunchuk extension board, talking to it through SPI that’s for sure — the justification being that this has a much better bandwidth than the MIDI port.

    What I was thinking about was turning this board into a standalone version. I got your point about using the full Wiimote through BT on a computer.

  • @Luap: you are right with your point, but still… what about people who prefer to work without a computer? On many scenarios turning Wi-fi and bluetooth off can increase audio performance or solve drop-out issues so using these kind of devices is a bit of a hassle… just o say that there is plenty of reasons why a device like this could be great!

  • Sure it could be great! Im not ruling that out.. I was merely mentioning something Olivier might not have been aware of. It would be a bummer to get stuck into a project, only to realise that there was already a good way to do much the same thing..
    That said, I thought wireless/bluetooth drop outs and related audio performance issues were largely a thing of the past. I don’t recall the last time I had anything like that happen..

    I see Olivier is taking a different route by going standalone though. Which is all good :) I guess this could be more useful still, if whatever he is planning to make will also behave as a standalone Nunchuk to midi converter. IE, It could control other midi hardware too?
    Midipal, nunchuk edition?? ;)

    But on a related note.. For you folk that do have a Wii controller kicking about, and never tried it as a midi controller.. Do give it a go! It is huge fun! And genuinely useful, and not just some novelty. It’s all quite simple to set up and flexible with Osculator (I’ve not tried GlovePie on a PC though)

  • Osculator rocks.

    What I plan to make will primarily interface with my next project (think of it as a “Nunchuk programmer”) ; but I’m wondering whether I go through the extra effort of adding 5 or 6 extra parts on the board and 100 lines of code to make it work as a standalone unit.

  • i want one – for each hand!

  • If you’re doing it anyway, then yes, add the 5-6 parts and code to make it standalone. That said, I’ve not been a huge fan of all this alternate controller stuff. Probably just stuck in my ways, but there you go.

  • Hello,

    a longtime lurker here, but as soon as this topic caught my eye I just couldn't help it and had to sign up ;-)

    this idea is just fabulous! how about a functionality like the samchilian:

    I just like the idea of playing relative notes with just a few buttons. the board could have inputs for two nunchuks as well.

    anyway, that's definitely a great idea and I'm definitely interested!
  • Sounds interesting
  • thinking about similar project since i saw this

  • I’ve seen them taped to guitars to control efx. Mostly it should be computer free,
    Buttons trigger on sequences/arpegiators/portemento on
    accelerators doing filter/vca
    some sort of force to scale with octave ranges limited to 1/2 octaves of midi note ranges, going wider would simply be un trainable for live work so put some user designed sysex loaded limits that can usb off software one time, pre-use.

  • Olivier, I’ve spotted this long time ago. Is there working prototype or you decided to bury this project?

    (i can be a beta tester, i have all for this except firmware)

  • I have built one and coded 75% of the firmware. Buried for the moment. It has simple modes like playing MIDI drums or sending CCs, but I had planned other modes to control pads or arps. Too gimmicky and too unreliable for performance for my likings…

  • What about Kinect? would do a Theremin pretty easily if you invest the time in the image processing algorithm (could be CPU intensive though).

    Microsoft even has a prototype of control using speakers and the doppler effect.

  • Re. the Kinect thing, you have to do a lot of processing on the depthmap image to get useful data from it. On a desktop computer, you can offload that kind of stuff to the graphics card (essentially a massively-parallel computer in it own right, with specialist DSP for dealing with millions of pixels), but I imagine dealing with the kind of data-throughput and image-processing needed would put it way beyond the capabilities of the kind of cheap multi-purpose programmable chips Olivier works with. I’m not putting them down, it’s just they’re not designed for image-processing duties.


  • I thought the kinect was doing the processing and sending the precomputed depth-map to the USB host…

    Anyway, it’s not really the same category of stuff here… $100 big USB device vs $10 sensor with I2C interface…

  • Well the doppler effect approach would be cheap. You need a ultrasonic transmitter and a receiver.

  • ...uncovered arduino, connected motionplus, opened arduino forum and stuck into code =)
    @6581punk: IMHO this is the best solution

    just $3 at ebay.

  • @Pichenettes the Kinect computes a depthmap image, but doesn’t do anything else with it, you have to do the processing yourself.


  • if someone interested – here is arduino sketch for wii motionplus gyroscope. All you need is midi jack, 2x220 resistors and cables. (Look to sketch header for connection info)
    roll axis for note, yaw for cutoff and pitch for resonance by default.

  • PCB was extracted from WM+
    During soldering TWI cable i’m assidentally knock off 0402-sized capacitor near IDG600 gyroscope chip (C12 at the bottom). No luck searching datasheet. No luck using .22uf like in IDG300. I’ve desoldered identical one, soldered legs to it. Insert into multimeter – and measured .1uf =) Than hours of searching for broken cellphone pcb, its schematic and needed capacitor, desoldering, soldering etc. Next time i’ll be more attentive. My son would never forgive me cannibalizing of second MotionPlus :D
    Next i’ve enabled it’s internal 3.3V regulator with wire jumper (Arduino Nano not able to power 3.3v devices without usb connection, the regulator is inside FTDI chip)
    Connected unused Shruthi MIDIout pins to gnd + 5v to power controller by MIDI cable (later realized that it was bad idea. or i just need decoupling caps)
    Added midi activity led + two buttons, one for “Note on” another for gyroscope recalibration.
    And here it is in action
    Hardware is finished. There’s still lot off things to do with code (first shrink it to fit atmega8, i need my Arduino Nano back =) but i’m very tired.

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