Wii-motified laser cutter refocuses for contoured cutting

Still laser cutting all of your parts in 2D? Not the folks over at [Just Add Sharks]. With a few lines of code and an in-tact Wii-Mote, they’ve managed to rig their laser cutter to dynamically refocus based on the height of the material.
The hack is cleanly executed by placing the Wii-Mote both at a known fixed distance-and-angle and within line-of-sight of the focused beam. Thankfully, the image-processing is already done onboard by the Wii-Mote’s image sensor, which simply returns the (x,y) coordinates of the four brightest IR points in view. As the beam moves over the material, the dot moves up or down in the camera’s field-of-view, triggering a refocus of the laser as it cuts. Given that the z-axis table needs to readjust with the contour, the folks at [Just Add Sharks] have slowed down the cutting speed. Finally, it’s worth noting that the Wii-Mote was designed to detect IR LEDs, not a 10600-nanometer laser beam, but we suspect that the Wii-Mote is receiving colors produced by the fluorescing material itself, not the beam. Nevertheless, the result is exactly the same–a dynamically refocusing laser!
Now that [Glowforge] has released a continuously-refocusing laser cutter implemented with stereoscopic cameras, it’s great to see the community following in their footsteps with a DIY endeavor. See the whole system in action after the break!

http://hackaday.com/2015/11/01/wii-m...oured-cutting/