Last year, [Alvaro] built a laser turret robot for the DEFCONBOTs competition. It worked pretty well, but this year, he decided to step it up a notch. Now instead of moving the entire robot laser array, he’s using galvanometers to move only the laser — he’s essentially built a mini laser projector.
A galvanometer is basically a very sensitive ammeter that moves — it can also be used as a very precise electro-mechanical actuator, for say, moving a tiny mirror. As you can imagine, you can actually build home-made galvanometers — but it’s really not that easy. Instead, [Alvaro] opted to order a few laser show controllers on eBay, and hack his way to a solution — we approve.
Wiring up the galvanometers and making some circuitry for them was the easy part. The tricky part is automating the system.
You see before when the laser was attached to the camera, it was pretty simple. The laser shoots where the camera shoots. Any simple image recognition software would work. But now that the two are independent, it’s not that simple. If you could mount everything precisely, you could use trig to calculate laser angles and the resulting locations, but the problem is… mounting everything precisely:
If I was a machining/CAD wizard, I could mount the laser, galvanometers, and camera precisely enough that I could use some math to calculate angles/depths and figure out where the laser is going.
As I mentioned previously though, I am no CAD wizard, and my mechanical skills are… lacking. With no mechanical solution to the problem, I had to start getting creative with software.
His software solution is pretty cool. It requires calibration by creating a grid of pre-defined points, but from there, the possibilities are pretty endless. Take a look.
And now some ping pong balls as targets.
And finally — a moving train.
Anyone remember that laser targeting mosquito system? Why aren’t those in production yet! Get on it [Alvaro]!
Filed under: laser hacks
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