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Someone recreated the arcade version of Astroids (vector graphics) using an expensive laser projector. Could something like this project pull that off on a smal

by kgwxd 8y ago

Someone recreated the arcade version of Astroids (vector graphics) using an expensive laser projector. Could something like this project pull that off on a smaller scale? It'd be like a DIY Vectrex, and it would be glorious.

sigwinch28 8y ago
Here's a standup maths video about that projector: https://www.youtube.com/watch?v=FkHjG759ABY https://www.youtube.com/watch?v=FkHjG759ABY
bloopernova 8y ago
Well, thank you for the unexpected nostalgia-gasm. As a certain set of divorced absentee fathers are wont to do, my father would show up every 18 to 24 months, shower me with gifts, then disappear again in a puff of Ferrari exhaust. Those gifts would always be slightly off from what I wanted, usually reflecting his own tastes rather than what a 10 year old might want. One such time I got a Vectrex, I was the only kid who had one and as such it didn't really get much use beyond my brother and I. The cheapo ZX Spectrum 48k got much more use because I could swap games with friends, use hardware with their systems, etc etc. (Other items he'd buy me throughout the years: a Yamaha SHS10 keytar rather than a full size keyboard I requested. An expensive SLR camera whose lens drank batteries when I asked for clothes. An Atari ST that wasn't the same as the other kids' STs in a way I don't remember, but it couldn't do everything their machines could. All this sounds like I'm horrifically entitled and bitter; I was, back then. He's dead now, and my anger has been swamped by sad regret) But the Vectrex and its vector graphics was pretty amazing. Razor sharp lines at a time when most systems struggled to do CGA. But I remember the games being repetitive and limited by the single colour screen.
- stevekemp 8y ago
  The Vextrex was a little repetitive, but the way they tried to make it colourful with the gel-overlays was kinda endearing. I received one, as a cast-off gift from a richer cousin. But mostly I spent my time on the ZX Spectrum. More games to play, more coding to be done on it, and I spent hours hacking games for extra/infinite lives.
cr0sh 8y ago
Unfortunately, no. This project was done as a raster display, not a vector display. Well done work, but not what you want for vector Asteroids. If you wanted to DIY a laser vector Asteroids, you'll need to build your own galvo system in some manner. Google around for "DIY Laser Galvos" - you'll find a few people who have done it. Note: It isn't simple, nor easy. In fact, it'd probably be cheaper to buy some second-hand galvos off ebay than the time and cost to build it yourself. It would depend on whether you are more interested in DIY-ing the laser game, or if you are interested in learning how to build a laser light vector scanning system from scratch. It's kinda the same question when people learn how "simple" it is to build their own CO2 laser - they think "Yes, now I can build a cheap laser cutter!" But if you look into the forums about homemade laser building, every single one will advise you against that path, because it is a foolhardy thing to do - you will end up spending way more money for way less of a result than if you simply purchased the laser cutter (or at least the tube and such) outright, pre-built. Because building a laser is not as easy as it looks. Same here. So weigh what it is you are trying to do and learn; maybe it would be worth it to you - and the game is really secondary. That said - check out this instructable (and be sure to expand and read ALL of the comments - I mention something in there that may potentially be possible): https://www.instructables.com/id/Moving-Things-With-Printed-Circuit-Boards/ https://www.instructables.com/id/Moving-Things-With-Printed-... IOW - there may be a way to make a very cheap capacitive feedback "galvo" using custom etched quadrature magnetic positioning PCBs. I think the concept is sound, but the question would be "throw" of the laser, and speed, and whether ringing/overshoot of the mass could be controlled using such a system...
- regularfry 8y ago
  That feels a lot more complicated than it needs to be. Have you ever taken apart a mid-range camera with an electromechanical image stabilizer? It's a triangular plastic plate with a lens in the middle, a pin at one corner, and a couple of rare earth magnets at the other two. There are two voice coils mounted next to the plate to repel or attract the magnets, and a light spring to center the whole thing. Remarkably simple device, doing a remarkably similar job (modulo replacing the lens with a mirror if needs be).
ansible 8y ago
There's issues with doing this with a laser. The vector display used on Asteroids actually steered the beam to form each individual line, and could do it fast enough to draw all the objects on the screen at a decent refresh rate. Steering the electron beam is fast because that is all electronic. If you wanted to do a laser vector display, that's difficult because you'd be physically moving something (the laser or the mirror). Doing that fast is super difficult. You could create a laser raster display (as in the linked blog post), but that won't look or work the same as a vector display.
dreamcompiler 8y ago
In principle, yes. In practice, it's painful. I built a vector laser projector back in the 80s when lasers were huge and my XY galvanometer probably cost $1000, but my college was paying for it, so why not? I drove the thing with a Fairlight CMI, onto which I painstakingly drew the parametric equations of X and Y with a light pen. (Nowadays I'd write a program to do that bit for me.) The biggest problem -- other than the cost -- was the fact that the galvos are not perfect: They exhibit lag and resonance at certain frequencies, so you have to cancel all that out and overdrive them in particular ways. This is probably easier today than then, and it can be done more easily with closed-loop feedback than the open-loop way I did it, but it looked amazing.

by kgwxd 8y ago

sigwinch28 8y ago

Here's a standup maths video about that projector: https://www.youtube.com/watch?v=FkHjG759ABY https://www.youtube.com/watch?v=FkHjG759ABY

bloopernova 8y ago

Well, thank you for the unexpected nostalgia-gasm. As a certain set of divorced absentee fathers are wont to do, my father would show up every 18 to 24 months, shower me with gifts, then disappear again in a puff of Ferrari exhaust. Those gifts would always be slightly off from what I wanted, usually reflecting his own tastes rather than what a 10 year old might want. One such time I got a Vectrex, I was the only kid who had one and as such it didn't really get much use beyond my brother and I. The cheapo ZX Spectrum 48k got much more use because I could swap games with friends, use hardware with their systems, etc etc. (Other items he'd buy me throughout the years: a Yamaha SHS10 keytar rather than a full size keyboard I requested. An expensive SLR camera whose lens drank batteries when I asked for clothes. An Atari ST that wasn't the same as the other kids' STs in a way I don't remember, but it couldn't do everything their machines could. All this sounds like I'm horrifically entitled and bitter; I was, back then. He's dead now, and my anger has been swamped by sad regret) But the Vectrex and its vector graphics was pretty amazing. Razor sharp lines at a time when most systems struggled to do CGA. But I remember the games being repetitive and limited by the single colour screen.

stevekemp 8y ago
The Vextrex was a little repetitive, but the way they tried to make it colourful with the gel-overlays was kinda endearing. I received one, as a cast-off gift from a richer cousin. But mostly I spent my time on the ZX Spectrum. More games to play, more coding to be done on it, and I spent hours hacking games for extra/infinite lives.

cr0sh 8y ago

Unfortunately, no. This project was done as a raster display, not a vector display. Well done work, but not what you want for vector Asteroids. If you wanted to DIY a laser vector Asteroids, you'll need to build your own galvo system in some manner. Google around for "DIY Laser Galvos" - you'll find a few people who have done it. Note: It isn't simple, nor easy. In fact, it'd probably be cheaper to buy some second-hand galvos off ebay than the time and cost to build it yourself. It would depend on whether you are more interested in DIY-ing the laser game, or if you are interested in learning how to build a laser light vector scanning system from scratch. It's kinda the same question when people learn how "simple" it is to build their own CO2 laser - they think "Yes, now I can build a cheap laser cutter!" But if you look into the forums about homemade laser building, every single one will advise you against that path, because it is a foolhardy thing to do - you will end up spending way more money for way less of a result than if you simply purchased the laser cutter (or at least the tube and such) outright, pre-built. Because building a laser is not as easy as it looks. Same here. So weigh what it is you are trying to do and learn; maybe it would be worth it to you - and the game is really secondary. That said - check out this instructable (and be sure to expand and read ALL of the comments - I mention something in there that may potentially be possible): https://www.instructables.com/id/Moving-Things-With-Printed-Circuit-Boards/ https://www.instructables.com/id/Moving-Things-With-Printed-... IOW - there may be a way to make a very cheap capacitive feedback "galvo" using custom etched quadrature magnetic positioning PCBs. I think the concept is sound, but the question would be "throw" of the laser, and speed, and whether ringing/overshoot of the mass could be controlled using such a system...

regularfry 8y ago
That feels a lot more complicated than it needs to be. Have you ever taken apart a mid-range camera with an electromechanical image stabilizer? It's a triangular plastic plate with a lens in the middle, a pin at one corner, and a couple of rare earth magnets at the other two. There are two voice coils mounted next to the plate to repel or attract the magnets, and a light spring to center the whole thing. Remarkably simple device, doing a remarkably similar job (modulo replacing the lens with a mirror if needs be).

ansible 8y ago

There's issues with doing this with a laser. The vector display used on Asteroids actually steered the beam to form each individual line, and could do it fast enough to draw all the objects on the screen at a decent refresh rate. Steering the electron beam is fast because that is all electronic. If you wanted to do a laser vector display, that's difficult because you'd be physically moving something (the laser or the mirror). Doing that fast is super difficult. You could create a laser raster display (as in the linked blog post), but that won't look or work the same as a vector display.

dreamcompiler 8y ago

In principle, yes. In practice, it's painful. I built a vector laser projector back in the 80s when lasers were huge and my XY galvanometer probably cost $1000, but my college was paying for it, so why not? I drove the thing with a Fairlight CMI, onto which I painstakingly drew the parametric equations of X and Y with a light pen. (Nowadays I'd write a program to do that bit for me.) The biggest problem -- other than the cost -- was the fact that the galvos are not perfect: They exhibit lag and resonance at certain frequencies, so you have to cancel all that out and overdrive them in particular ways. This is probably easier today than then, and it can be done more easily with closed-loop feedback than the open-loop way I did it, but it looked amazing.