While it may not be a Glowforge, this Wiimote hack is pretty slick.
Chances are that it’s been quite a while since the last time you played Mario tennis or went bowling on your Nintendo Wii. But as we’ve seen with other obsolete devices, there’s no reason to throw it away! In fact, the Wiimote’s unique design lends itself to several innovative projects, like one from Maker Martin Raynsford who has retrofitted the handheld controller into a fully-functional laser cutter.
Raynsford and the Just Add Sharks crew were inspired by the newly-revealed Glowforge 3D laser printer’s ability to autofocus as the head travels along complex curves during cuts and engraves. And so, they employed the Wiimote’s built-in infrared camera to refocus the laser based on the height of the material.
“The hardware automatically identifies these points and feeds back XY positions through a Bluetoth connection. The cutting laser on a laser cutter is an infrared beam, as it cuts through the surface of the material there is a moment where it is reflected off the material and the Wiimote is able to detect the location of the cut,” Raynsford writes. “The location data is fed back to a laptop and by comparing this point against the initial ‘in focus’ point we’re able to detect if the Z-axis needs to move up or down and by how much.”
The optical camera is calibrated to a ‘zero’ point the first time it sees the laser cut. The offset between the current dot position and the zero position is then converted into Z-height adjustments. A laptop sends the data to an Arduino Nano (ATmega328) that is connected between the laser cutter’s on-board controller and the Z-axis stepper motor driver. This gives it the ability to remain in focus throughout the duration of a cut.
“Our laser cutter moves the whole bed up and down to adjust the focal height. There is a lot of mass to move and it gains momentum so it isn’t able to adjust the Z-axis as fast as required. This is why it’s so noisy as it tries to keep up with the requested position,” Raynsford adds.
It should be noted, however, that there are a few drawbacks in the DIY laser cutter when compared to more professional-grade units. For one, the remote’s camera is only able to detect light sources 60 times a second, thereby causing a bit of a lag in the time that it changes height and the actual movement. What’s more, an increased mass on the cutting head prevents the machine from reaching its top speed of 50mm/second, and even if it could, the response time from the system would not be fast enough to cope with changes that quickly.
Conversely, the good news is that many of us have a Nintendo Wii collecting dust somewhere. The project itself was written using C# and Brian Peeks Wiimote Lib, which made hooking up the Wiimote as simple as a few lines of code. Perhaps this will offer a second lease on life for the gaming console!
Intrigued? See it in action above, or check out the Maker’s project page here.
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