Laser Galvos And An ESP32 Recreate Old-School Asteroids

Playing Asteroids now isn’t quite what it used to be when it came out 40 years ago. At the time, the vector-scan display was part of the charm; making do with an emulator running on a traditional raster display just doesn’t quite do it for purists. But if you manage to build your own laser-projector version of the game like [Chris G] did, you’re getting close to capturing some of the original magic of the game.

There’s a lot to unpack about this project, and the video below does a good job explaining it. Where the original game used a beam of electrons flashing inside a CRT to trace out each object in the game, [Chris] substituted an off-the-shelf two-axis galvanometer from eBay and a 5-mW laser LED. This can project a gamefield on a wall up to two meters on a side, far bigger than any version of the machine ever built. The galvos are driven by op-amp drivers and an SPI DAC on a custom PCB. And in comparison to the discrete logic chips and 6502 running the original game, [Chris] opted for an ESP32.

As interesting as the hardware for this is, the real story is in the software. [Chris] does an excellent job running through his design, making the bulk of the video feel like a master class in game programming. His software is from scratch — no emulations here. As such it doesn’t perfectly reproduce the original games — no flying saucers and no spaceship explosion animations (yet) — but when coupled with the laser vector display, it certainly captures the feel of the original.

Being devoted Asteroids fans from back in the day, this one really pushes our buttons. We’ve seen laser-based recreations of the game before, but this one makes us think we can finally afford to recapture the glory of our misspent youth.

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Laser Artistry Hack Chat

Join us on Wednesday, April 1 at noon Pacific for the Laser Artistry Hack Chat with Seb Lee-Delisle!

It’s hard to forget the first time you see a laser light show. A staple at concerts starting in the 1980s, seeing a green laser lance out over the heads of tens of thousands of screaming fans to trace out an animated figure or pulsating geometric shapes was pure fascination, and wondering how it was all done was half the fun. As we all know now, it was all done with mirrors, tiny and connected to low-inertia galvanometers capable of the twitchiest of movements, yet precise enough to position the beam of light exactly where it needed to be to create the desired illusion. It was engineering, science, and art all wrapped up into one package.

Fast forward to the present day, and laser show technology has certainly advanced. Bulky laser tubes have been replaced by solid-state devices, more colors are available, and galvo designs have improved. The art and artistry of the laserist have grown with the tech, which is where our guest Seb Lee-Delisle comes into his own. We’ve featured some of Seb’s work before, like an Asteroids laser vector display and enormous public laser displays. And now he’ll stop by to talk about how the art and the tech combine in his hands to produce something much greater than the sum of its parts.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, April 1 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Laser Galvo Control Via Microcontroller’s DAC

Mirror galvanometers (‘galvos’ for short) are the worky bits in a laser projector; they are capable of twisting a mirror extremely quickly and accurately. With two of them, a laser beam may be steered in X and Y to form patterns. [bdring] had purchased some laser galvos and decided to roll his own control system with the goal of driving the galvos with the DAC (digital to analog) output of a microcontroller. After that, all that was needed to make it draw some shapes was a laser and a 3D printed fixture to hold everything in the right alignment.

The galvos came with drivers to take care of the low-level interfacing, and [bdring]’s job was to make an interface to translate the 0 V – 5 V output range of his microcontroller’s DAC into the 10 V differential range the driver expects. He succeeded, and a brief video of some test patterns is embedded below.

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