Chapter Five : WiiMote tracking (Hardware solution)

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New for 2011 – check out the MIDI Camera
– gesture control with no Bluetooth, or even a PC!

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Last year I tried to find out if it were possible to connect a PixArt blob tracking camera directly to the Arduino. I knew they both spoke I2C and in theory it should be possible. I posted on the Wiimote project forum to see what was out there.

(I knew that if I gave it long enough, someone else would crack the code.)

Now that they have, it’s time to try to create a hardware only tracking Laser Harp. There are two sources of info out there – one from Johnny Lee himself, and the other from Kako – here is the Babel Fish translation of the original Japanese site.

This is new ground for me, and so I will be using a breadboard first, and soldering things down later.

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First off,  we need to get the sensor out of the WiiMote, you can either desolder it, or just cut the board (bye bye WiiMote).

Next we need to provide a 25Mhz clock signal, and 3.3V regulator to power the camera.

The Arduino does have a 3.3v line, but I think you are better off with a separate regulator.

Now the *really* tricky bit. We need to add an LTC4301L  5v/3.3v I2C buffer chip. These only come in MSOP form factor and are just like surface mount – very difficult to solder.  Here is everything you need to know about soldering surface mount components.

Adapters are available to convert the MSOP to more manageable DIP form factor here.

I can just about solder these things now, but it took me a couple of goes to get “the knack”.  I ordered 3 of the chips – just in case.

Downloading and running Kako’s sketch should get the whole thing running, like this:

(With a quick appearance by my daughter…)

I just finished the first pass of the C++ object library for accessing the WiiMote/Pixart sensor from an Arduino. A simple example included with the library.

Download Library

I then mounted this detector along with two standard TAOS detectors in a neat metal box I found.

The second Arduino will relay the MIDI data coming from the harp body, and mix in the MIDI controller information based on the readings taken from the Pixart sensor. This is why the MIDI output port has been moved to the detector case.

I have some simple serial relay software running for the MIDI data, I just need to get the ‘merge’ function going.

But for now, it’s time for a break…