Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
No, Brad was not the founder of NewTek. He did do early designs of the Toaster. - John Derp! Checked, he built the first Video Toaster but not the company. https://en.wikipedia.org/wiki/Brad_Carvey Thanks for the correction! -- Ethan O'Toole
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
At 05:13 PM 7/19/2016, et...@757.org wrote: >I'm sure you know the thing about Garth/Dana Carvey? Him mentioning the Unix >book in Waynes World was a nod to his brother, his brother founded NewTek the >company behind the Amiga video toaster and the current NewTek Tricaster stuff? No, Brad was not the founder of NewTek. He did do early designs of the Toaster. - John
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
The only ones worth using that I'm aware of are Scream Tracker and Impulse Tracker and neither was around in the 16 bit ISA days pre-386, IIRC. I doubt Scream Tracker would be able to function on a 286 anyhow. It puts a 486DX2/66 at about 50% CPU load, from my recollection. The Amiga trackers were more efficient, but you got fewer channels, too. OctaMED was 8-channel and that seemed massive until it wasn't. IT was VGA but I think Scream Tracker was a 50 line text mode or something. I guess it depends if Scream Tracker used protected mode. Hmm intarnet says 386s were out during 1990 which was the year the more popular Scream Tracker was released. I swear my friend was playing coma.s3m on his Northgate 286-16 via PC Speaker Several made it there over the years. I can't remember which ones, but I do remember one day I was listening to Nectarine Radio and heard one of my own Protracker MODs. That was awesome. Awesome! Ahhh, those air-car-mounted-on-hydraulics "ride" thingys? Huh. Laser disc was always a cool thing, too. Remember "Time Traveler" ? That "holographic" (it wasn't really but it looked damn cool) game were the characters appeared in front of some kind of curved mirror volumetric display uhm, thingamabob? It used a Laserdisc too. Of course I loved Space Ace and Dragons Lair along with every other self-respecting geek, too. Also, my favorite was called "Thayer's Quest" in which you were a wizard's apprentice. Yes. There is an arcade in Chicago called Galloping Ghost which has both of the Sega holographic machines, and some of the laserdisc games like Space Ace and Dragons Lair. In the arcade world, due to the unreliability of the laserdisc players often used in games like Dragons Lair (it uses a real HeNe laser tube!) it's okay for people to move them to the MS-DOS Daphne replacement system and such. Normally MAME/emulation is frowned upon by collectors but the LD games get an okay. The way they work is amusing, the game board drives the LED score and just watches for joystick directions and sends the chapter skip commands via RS-232 or RS-422 to the serial port equipped commercial LD player in the cabinet. Pretty simple but legendary. Most commercial real estate weasels think you are the next "sucker" coming through the door. They seem to believe that some old crufty warehouse that's been empty for a decade is actually worth the ridiculous rents they charge. You'd think it'd be better to have the buildings occupied and someone giving you a bit or two to cover the property taxes, but they still don't seem to see their clients as anything more than walking cash registers. It's definitely a hard slog to find a screaming deal on space. All the hacker-spaces here in big-D have lots of folks pitching in to make ends meet. The first one here with an Ethan-style laser arcade will definitely get my membership dues. Hah awesome! Then there is the problem that nobody but old dudes remember how fun/cool arcades could be, back in a time when they looked a lot more like nightclubs. I remember them so crowded you had to go out for some fresh air. Flynn's Arcade may never live again, but it's still a paradigm of cool in my mind. Then again, I'm probably too old now to adjudicate "cool" for anyone. If you do open an laser-illuminated LED-walled arcade, let us all know so we can put you on the cctalk road-trip map. We'll rent a bus in Seattle, and drive to your place (or visa versa). I nominate Fred to run the logistics. I'll drive. :-P I help with an event each year called MAGFest which is currently in the DC area. We had 278 arcade cabinets in the arcade room and a decent deployment of classic computers in the museum. The attendance is 20,000 people or so -- it's a large event. Much of it is video game music related, and there is a ton of history and classic computer tie ins there. All the synth chips all the machines. The event is an insane amount of work though, I think it was 14 26' penske trucks some of which made 3 trips full of arcade cabinets, and the computer museum stuff occupied 2/3rds of a truck and was all owned by 3 people (just their personal stash.) No big metal mostly plastic micros but it's all hands on. There is a big arcade event in Seattle / Tacoma that has 450+ games, and there is CAX in California which just happened that has a large collection. They have a lot more people with lower numbers of games from what I understand where MAGFest has a handful of collectors with very large collections. There is definitely interest in the retro computer stuff growing outside of the age group the reminisces about it. There is also some cross over I think between the arcade and classic computer (plastic micro) crowd. -- Ethan O'Toole
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On Wed, 20 Jul 2016, et...@757.org wrote: > Very cool! I'm a.d.d. a bit with hobbies. On the synth side I recently > picked up a Roland MT-32, so that was an achievement unlocked. Hope to > find an Oberheim Matrix 6 at some point. I'm not a keyboard guru like some on the list, but I've owned a Roland FP-9 and Alesis DG8. Now I use a Yamaha Clavinova. I miss the DG8, but I traded it off once it's internal amp started fritzing out. > I started computeres on Atari 800XL, then next computer was family's > Tandy 1000SX. I had a friend with an Atari 800XL and I was very impressed with it. I remember a few demos (one with a metallic rendered robot walking toward you, I remember was most impressive). I was surprised that it was just an 8bit machine. At first I thought it might have been 16 bit! > At some point ended up with a Sound Blaster 1.0 in that (Still have the > SB.) I don't remember if there was ever a tracker on that, but I > remember Scream Tracker on the 386 (same sound card IIRC.) The only ones worth using that I'm aware of are Scream Tracker and Impulse Tracker and neither was around in the 16 bit ISA days pre-386, IIRC. I doubt Scream Tracker would be able to function on a 286 anyhow. It puts a 486DX2/66 at about 50% CPU load, from my recollection. The Amiga trackers were more efficient, but you got fewer channels, too. OctaMED was 8-channel and that seemed massive until it wasn't. > Spent a lot of time messing with Scream Tracker and Renaissance Composer > 669. Yes! I almost forgot about Composer, that was another good one. > If you haven't looked, look on the hornet mod archive to see if any are > on there? Several made it there over the years. I can't remember which ones, but I do remember one day I was listening to Nectarine Radio and heard one of my own Protracker MODs. That was awesome. > There was recently a video from popular artist deadmau5 where he was > driving around interviewing some DJ and he asked the guy if he used to > mess with ScreamTracker and all that -- I was pretty shocked. He was just showing proper street cred. +1 Deadmou5 > Interesting! Never seen the show, we tried to go to it once while at > Defcon but messed up on the time. So they're still running it on an > Amiga? That's awesome! It took some extra hard Googling to find anything about it. The only time I'd even heard about it was when I was actually in Vegas working as a Def Con goon. > Some of the amusement parks had ride simulators that used Amiga + Laser > disk. It's interesting where the Amiga found it's niche. Ahhh, those air-car-mounted-on-hydraulics "ride" thingys? Huh. Laser disc was always a cool thing, too. Remember "Time Traveler" ? That "holographic" (it wasn't really but it looked damn cool) game were the characters appeared in front of some kind of curved mirror volumetric display uhm, thingamabob? It used a Laserdisc too. Of course I loved Space Ace and Dragons Lair along with every other self-respecting geek, too. Also, my favorite was called "Thayer's Quest" in which you were a wizard's apprentice. > Very cool! I always think about trying to do some sort of music venue > with a focus on live music + video recording / live streaming, or > arcades + old computers. > Here in Northern VA everything is crazy expensive tho, so coming across > commercial space for pennies is difficult (at this moment.) Most commercial real estate weasels think you are the next "sucker" coming through the door. They seem to believe that some old crufty warehouse that's been empty for a decade is actually worth the ridiculous rents they charge. You'd think it'd be better to have the buildings occupied and someone giving you a bit or two to cover the property taxes, but they still don't seem to see their clients as anything more than walking cash registers. It's definitely a hard slog to find a screaming deal on space. All the hacker-spaces here in big-D have lots of folks pitching in to make ends meet. The first one here with an Ethan-style laser arcade will definitely get my membership dues. Then there is the problem that nobody but old dudes remember how fun/cool arcades could be, back in a time when they looked a lot more like nightclubs. I remember them so crowded you had to go out for some fresh air. Flynn's Arcade may never live again, but it's still a paradigm of cool in my mind. Then again, I'm probably too old now to adjudicate "cool" for anyone. If you do open an laser-illuminated LED-walled arcade, let us all know so we can put you on the cctalk road-trip map. We'll rent a bus in Seattle, and drive to your place (or visa versa). I nominate Fred to run the logistics. I'll drive. :-P -Swift
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
I knew it! Piano, bass, violin, and guitar, here. I play them all badly but guitar a little less badly. I've been an amateur for about 10 years and I've been taking guitar lessons for about three years, now. Sax, eh? Cool. I've never tried a reed-based instrument. Very cool! I'm a.d.d. a bit with hobbies. On the synth side I recently picked up a Roland MT-32, so that was an achievement unlocked. Hope to find an Oberheim Matrix 6 at some point. You have all the cool sound gear you need if you have an ST and a machine with a GUS! Well maybe an Amiga with Octamed or Protracker, but Scream Tracker and Impulse Tracker also rocks fairly hard with a GUS, so never mind. :-) I started computeres on Atari 800XL, then next computer was family's Tandy 1000SX. At some point ended up with a Sound Blaster 1.0 in that (Still have the SB.) I don't remember if there was ever a tracker on that, but I remember Scream Tracker on the 386 (same sound card IIRC.) Spent a lot of time messing with Scream Tracker and Renaissance Composer 669. As you can tell, I like trackers. I wrote a few MOD/IT/S3M files "back in the day". If you haven't looked, look on the hornet mod archive to see if any are on there? There was recently a video from popular artist deadmau5 where he was driving around interviewing some DJ and he asked the guy if he used to mess with ScreamTracker and all that -- I was pretty shocked. Ah... I finally found some mention of it. Check this out: "The light and sound spectacular runs on a master show controller and three sub-systems. The controller runs Stage Manager 3000 software on an Amiga computer originally installed when the show began in 1995. Murphy said the master controller sends commands to the video-display controller, light console and digitally automated audio system. The audio system, a recently upgraded LCS Matrix 3 system, distributes 550,000W of sound through 220 remote amplifiers located throughout the outdoor mall." From: http://www.signweb.com/content/night-lights Interesting! Never seen the show, we tried to go to it once while at Defcon but messed up on the time. So they're still running it on an Amiga? That's awesome! Some of the amusement parks had ride simulators that used Amiga + Laser disk. It's interesting where the Amiga found it's niche. Whoa, very neat. When I was in college I used to run shows out of an old machine shop in an industrial part of town. It started as just a practice place. However, I knew a bunch of artists. They weren't just other college kids but artists who are pretty well known in the area and responsible for large public works etc... They all had daughters, you see... Anyhow, they talked me into letting them setup some art "openings" at this same little dinky venue I had going. One of them was an electrical engineering student who would come up from Texas Tech and cover the place with LED matrices that he had built. It was really impressive tech for the 1990s. He could do things like color cycling, and display static frames, but not animation. It always brought in lots of folks (200-800 per show usually) who were impressed by our tiny art shows with the "Light Room" display. People gave canned food or $$$ to get in and we raised a bit of food and money for charity that way, too. Very cool! I always think about trying to do some sort of music venue with a focus on live music + video recording / live streaming, or arcades + old computers. Here in Northern VA everything is crazy expensive tho, so coming across commercial space for pennies is difficult (at this moment.) -- Ethan O'Toole
RE: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On Tue, 19 Jul 2016, Mark Green wrote: > I don't know a lot about data transmission, my main application is > display. Thanks anyway for the informed reply. Do you happen to know the best place to view large format holograms? I'm just looking for your personal opinion, since you seem to be in the know about such things. I've been fascinated with holograms since I was a kid (ie.. the National Geographic comment). > The mathematics behind data transmission and display are similar, they > are based on wave propagation and diffraction and lots of Fourier > transforms. FFT is a wonderful and amazing algorithm. It's akin to Diffie-Hellman in it's magicalness, to me. Without it, imagine how poor (or non-existent) some technologies would be! > The laser power is not overly important, it's the resolution of > diffraction pattern or hologram that you produce. It's a very redundant > coding scheme, so part of the signal can be lost and you can still > recover all the information. Hmm, I'm guessing holograms have their own redundancy methods. I've seen Reed-Solomon matrices for such things, but that's the only one I know about. People write their Ph.D thesis on such things, so I'm not even a hobbyist, just an admirer of such tech. -Swift
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
I wouldn't be doing that. I cited the cg6 by way of contrast. How the points get into the display hardware is still open, but a framebuffer seems unlikely to be involved. (I suppose a framebuffer with something like DVI-D could be used as a way to continuously replay sequences very fast, but it has its limitations. I'd rather build a hardware ring buffer, but I tend towards hardware hackery.) Ah gotcha. In the laser show world there are gadgets properly called DACs, that usually connect to a host computer via USB, ethernet, or in the old days parallel port or PCI/ISA bus. They usually have 8 to 24 bits per channel, and will have channels for X, Y, then colors (Red, blue, green for diode based systems -- or some have a lot more channels as it's possible to have different sets of the same color on different wavelengths. 445nm blue looks a lot different than the 473nm blue, etc.) The Etherdream is the open hobbyist ethernet/USB connected device and runs around $200. The Pangolin FB3 is Pangolin's USB and the FB4 is ethernet. The pangolin units mostly only work with Pangolin stuff when it comes to modern DACs but the Etherdream has more hobbyist type stuff using it. There is an "industry" pinout for the DB25 called ILDA that specifies the color and XY pins, safety interlocks and what not. Some DACs are differential signalling for running over longer cables. The old school Pangolin hardware is called QuadMod boards, so if you find a QuadMod card in an Amiga or a QuadMod32 in an ISA PC that's what those are. The QuadMod2000 runs on PCI computers, but still approaching classic since it was a Windows 2000 product. -- Ethan O'Toole
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On Tue, 19 Jul 2016, et...@757.org wrote: > I live in Virginia but go to a number of events every year. I dabble > with music a little, have some synths and midi hardware (and of course > an Atari ST setup, and a luggable Pentium 200 with a SB/GUS and Voyetra > Sequencer!) Also dabble a little with saxophones but it's been a while! I knew it! Piano, bass, violin, and guitar, here. I play them all badly but guitar a little less badly. I've been an amateur for about 10 years and I've been taking guitar lessons for about three years, now. Sax, eh? Cool. I've never tried a reed-based instrument. You have all the cool sound gear you need if you have an ST and a machine with a GUS! Well maybe an Amiga with Octamed or Protracker, but Scream Tracker and Impulse Tracker also rocks fairly hard with a GUS, so never mind. :-) As you can tell, I like trackers. I wrote a few MOD/IT/S3M files "back in the day". > Hmm interesting! https://en.wikipedia.org/wiki/Scala_%28company%29 No > mention of freemont street but their current market is digital signage. > That would have been one of the earliest LED video screens ever! Ah... I finally found some mention of it. Check this out: "The light and sound spectacular runs on a master show controller and three sub-systems. The controller runs Stage Manager 3000 software on an Amiga computer originally installed when the show began in 1995. Murphy said the master controller sends commands to the video-display controller, light console and digitally automated audio system. The audio system, a recently upgraded LCS Matrix 3 system, distributes 550,000W of sound through 220 remote amplifiers located throughout the outdoor mall." From: http://www.signweb.com/content/night-lights > I'm sure you know the thing about Garth/Dana Carvey? Him mentioning the > Unix book in Waynes World was a nod to his brother, his brother founded > NewTek the company behind the Amiga video toaster and the current NewTek > Tricaster stuff? I did know some of that story, but not all. That's really cool. > Also, you can put together your own freemont-street-living-room at not > totally insane prices now. I put together this LED video screen [...] Whoa, very neat. When I was in college I used to run shows out of an old machine shop in an industrial part of town. It started as just a practice place. However, I knew a bunch of artists. They weren't just other college kids but artists who are pretty well known in the area and responsible for large public works etc... They all had daughters, you see... Anyhow, they talked me into letting them setup some art "openings" at this same little dinky venue I had going. One of them was an electrical engineering student who would come up from Texas Tech and cover the place with LED matrices that he had built. It was really impressive tech for the 1990s. He could do things like color cycling, and display static frames, but not animation. It always brought in lots of folks (200-800 per show usually) who were impressed by our tiny art shows with the "Light Room" display. People gave canned food or $$$ to get in and we raised a bit of food and money for charity that way, too. -Swift
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
> On Jul 20, 2016, at 9:12 AM, Mouse wrote: > >> As far as sending video from a computer frame buffer, I think it >> might be way too fast. > > I wouldn't be doing that. I cited the cg6 by way of contrast. How the > points get into the display hardware is still open, but a framebuffer > seems unlikely to be involved. (I suppose a framebuffer with something > like DVI-D could be used as a way to continuously replay sequences very > fast, but it has its limitations. I'd rather build a hardware ring > buffer, but I tend towards hardware hackery.) Given modern processor speeds, an obvious answer is to do it the same way the CDC mainframes drive the console: a program loop feeding coordinates to the interface. You just need a loop that takes less than the acceptable refresh interval (30-50 ms or so) which isn't hard to do. Especially since the deflection performance is likely to be the limiting factor. paul
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
> As far as sending video from a computer frame buffer, I think it > might be way too fast. I wouldn't be doing that. I cited the cg6 by way of contrast. How the points get into the display hardware is still open, but a framebuffer seems unlikely to be involved. (I suppose a framebuffer with something like DVI-D could be used as a way to continuously replay sequences very fast, but it has its limitations. I'd rather build a hardware ring buffer, but I tend towards hardware hackery.) /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
> On Jul 19, 2016, at 4:58 PM, Wayne Sudol wrote: > > Laser technology to draw things like this is used in photo typesetters. A > laser beam is focused onto a thin (about 1/2" thick) many sided (about 8 > sides i think) spinning mirror. Each facet of the mirror is cut differently > to deflict the beam up, down or center it on a sheet of moving paper or a > plate of sensitized aluminum. Depending on the typesetter, the spinning mirror might just be horizontal deflection, with vertical positioning provided by the film transport motor. But in any case, those are raster scan systems. It's very easy to scan a light beam in a regular pattern at high speed, with schemes like this. DLP (micro-mirror chips) are also raster systems. paul
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
Laser technology to draw things like this is used in photo typesetters. A laser beam is focused onto a thin (about 1/2" thick) many sided (about 8 sides i think) spinning mirror. Each facet of the mirror is cut differently to deflict the beam up, down or center it on a sheet of moving paper or a plate of sensitized aluminum. The more facets you have, the more 'cuts' you can have and the beam can be deflicted more each time it hits the mirror. The electronics is mainly used to control the timing/pulsing/power of the laser beam hitting the mirror. Using the same idea, a larger mirror could be used to deflict the beam more and shine it on any surface. Think of the scene in the Val Kilmer movie "Real Genius" where they advertise a part using a laser beam. Wayne Sudol Riverside Press-Enterprise A Digital First Media Newspaper 1-951-368-9945 On Tue, Jul 19, 2016 at 1:45 PM, jim stephens wrote: > > > On 7/19/2016 1:22 PM, Noel Chiappa wrote: > >> Those have been around for decades - I recall seeing them used to draw >> things >> on the sides of building,_many_ moons ago. >> > I know that the pen motors from Brush recorders were used eons ago. They > have frequency response that is very high, and if you had the power to > drive them would move very quickly. > > Also Oscilligraph motors could be used, and already had mirrors mounted on > the end. > > Piezo actuators could be mounted on the Brush motors and swung for a > second degree of motion as well. > > These were in use in the 70's if not earlier. > Thanks > Jim > > Gould Brush example: > GOULD-BRUSH-220-Strip-Chart-Recorder-Model-15-6327-57-POWERS-ON-SEE-DETAILS > http://www.ebay.com/itm/262507072142 > > Oscillograph: > HONEYWELL-1406-VISICORDER-OSCILLOGRAPH > http://www.ebay.com/itm/272248210671 > >
RE: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
I don't know a lot about data transmission, my main application is display. The mathematics behind data transmission and display are similar, they are based on wave propagation and diffraction and lots of Fourier transforms. The laser power is not overly important, it's the resolution of diffraction pattern or hologram that you produce. It's a very redundant coding scheme, so part of the signal can be lost and you can still recover all the information. -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Swift Griggs Sent: July 19, 2016 6:04 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: RE: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now)) On Tue, 19 Jul 2016, Mark Green wrote: > In my day job I work on computational holography and other forms of > esoteric 3D displays, so I can give you some insight in how these > things work. Holography is amazing. Do you know much about so-called "free space optical" data transmission? I worked with some gear a few years ago that could transmit & receive using multiple lasers at 1Gbit. I was fascinated with that stuff, but the vendor had their folks do all the alignment and installation. So, I didn't get to work with it much. I wonder if you've seen faster speeds than that. I also wonder what the power levels look like for those lasers and what distances the really serious ones can reach. Can they still work in bad weather? It seemed like the ones that I mentioned, still worked in the rain. -Swift PS: It was the May 1984 National Geographic cover that blew me away and made me forever respect holography. :-) --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
> From: Mouse > my impression is that they're only for pre-prepared displays, and only > some displays (notably those that don't involve the beam turning any > sharp corners My vague recollection is that they could do pretty sharp corners, but it's been decades. IIRC, they were multi-coloured. > Turning sharp corners is the hard part with mechanical deflectors like > mirrors, as it means very high acceleration of the mechanical parts. Probably the trick is to do what old voice-coil actuator drives did for multi-track seeks, which was to evenly accelerate up to maximum velocity, coast at that until you got close to the target track, and then evenly ramp down, so that the head assembly's radial velocity goes to 0 as you get to the target track. (If you're not moving enough tracks to do the whole thing, you only ramp up part-way, then ramp back down.) The RK05 drive did this with fancy analog circuits, but these days one would do it in software. I would assume one would do something similar with the mirror; evenly accelerate up to maximum slew rate, then back down at the end of the move, so that when one gets to the corner, the mirror is mostly stationary, and so not so much force is needed to sharply change directions. Of course, this might make the parts of the line where the mirror is moving slower brighter, but perhaps one could tweak the brightness to compensate. Noel
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On 19/07/2016 21:46, Mouse wrote: You'd probably know, then - what's the fastest way to deflect a laser beam? In particular, I'm wondering how practical it might be to take a laser and turn it into a vector display Turning sharp corners is the hard part with mechanical deflectors like mirrors, as it means very high acceleration of the mechanical parts. I haven't done the math to be sure, but, until/unless taught otherwise by testing, I'd feel dubious about clipping the X and Y signal bandwidths at anything lower than ~1MHz. If you want to experiment, you might try to find the mirror/coil assemblies from a Pioneer laserdisk player or similar. They consist of a small mirror mounted on a moving coil so as to turn on one axis through an angle of some +/-10deg (total 20deg). They're light enough to respond somewhere in the kHz (maybe 10s of kHz) range if you only need small deflections, rather than the full 20deg. I've got one here, but never got round to trying it out. -- Pete
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
Killer. I wish we were neighbors, Ethan. We'd be able to throw the most awesome block parties, I swear. I bet you are a musician, too. I live in Virginia but go to a number of events every year. I dabble with music a little, have some synths and midi hardware (and of course an Atari ST setup, and a luggable Pentium 200 with a SB/GUS and Voyetra Sequencer!) Also dabble a little with saxophones but it's been a while! Okay, after talking about the recent roots of that hobby, and in an effort to keep this slightly on topic, do you know anything about the original animations used on Freemont street in Las Vegas? I was told that at one time it was run from an Amiga using Scala "and some other stuff". If you haven't seen it, it's a giant (uhm, like 4 city blocks) color LED array and a big sound system. Hmm interesting! https://en.wikipedia.org/wiki/Scala_%28company%29 No mention of freemont street but their current market is digital signage. That would have been one of the earliest LED video screens ever! I'm sure you know the thing about Garth/Dana Carvey? Him mentioning the Unix book in Waynes World was a nod to his brother, his brother founded NewTek the company behind the Amiga video toaster and the current NewTek Tricaster stuff? Also, you can put together your own freemont-street-living-room at not totally insane prices now. I put together this LED video screen, it's a square meter of panels, the software screen scrapes Windows desktop sends it over gigabit: https://www.youtube.com/watch?v=78RUIGVvQ5E -- Ethan O'Toole
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
Yeah, me too, but my impression is that they're only for pre-prepared displays, and only some displays (notably those that don't involve the beam turning any sharp corners, such as Lissajous figures). My impression may, of course, have been - be - incorrect, which is what I'm asking for; if you've seen such displays involving sharp-corner turns of the beam and run-time chosen displays, then obviously my impression is incorrect and the technology exists. The devices are called Galvometers and they work like audio meters. There is in deed a mirror, and they are used in an XY pair. Old gas lasers used a RF driven crystal to select a specific wavelength of light (and deflect all other wavelengths.) Those crystal setups are known as Poly-chromatic acouso-optic modulation or PCAOM for short. The current fastest scanners that I know of on the market for laser show display would be the Pangolin Saturns. Next up would be something in the 6800 series from Cambridge Technology. The galvos can do sharp turns, text, and graphics. There is software for Linux that can do edge tracing and send it out of a modified sound card DAC (has to pass DC voltage?) to the X/Y scanner drivers. Most galvos have a feedback loop for inertial correction. The laser display world uses a test frame known as the ILDA (International Laser Display Association) and there is a performance benchmark in points per second, so 12,000 points per second is old spec, 30,000 points per second is a newer spec. Now people are claiming 60 and 90K on the modern, expensive, quality scanners. The Chinese stuff is mostly 30K and 40K. The old days 8 degrees was the scan width but now people push it way further. Old technology stored the laser show information on various formats for shows ... like 8 track multitrack reel to reel, and then the Alesis SVHS based ADAT machines were popular for a while. Now everything is directly driven from computer. Some of the old systems are being recovered here and there, and similar to vintage computers people pet them and clean them and take care of them. I'm pretty certain some old school stuff existed in the S100 world, but none of that has surfaced. There is also analog consoles and the like. As far as sending video from a computer frame buffer, I think it might be way too fast. Also, the more you scan and the faster you scan the laser power has to be higher. And there can also be issues with modulating the actual laser diodes. Direct solid state run at one rate and diode pumped solid state run at another rate. This is a random picking of a laser graphics show, projected on a scrim. It's from LD-2000 which would of been Windows 2000 to XP era software, but the show is pushed into a card that is a Motorola 68040 on a board with RAM where the card just runs the show once it's loaded. Pangolin's roots are on the Amiga so I've always grinned thinking they just put an Amiga on a board: https://www.youtube.com/watch?v=khVGAOLTaTA There are a few ports of MAME for running vector arcade games into laser projectors, the older hardware had quite a bit of flicker. There is also someone who has rebuilt, from scratch, several older analog consoles that had some fame. China really opened the floodgates with the availability of parts, and lots of projectors and low cost galvos. Before China a set of galvos could run a thousand or more dollars with the amps. And the PCAOM hardware would costs thousands. When I had the argon system I had picked it up from a NASA auction while hunting lasers, SGIs, and Suns. Everyone will probably cry when I say that one of the first NASA auctions I went to there was a Convex system there.
RE: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On Tue, 19 Jul 2016, Mark Green wrote: > In my day job I work on computational holography and other forms of > esoteric 3D displays, so I can give you some insight in how these things > work. Holography is amazing. Do you know much about so-called "free space optical" data transmission? I worked with some gear a few years ago that could transmit & receive using multiple lasers at 1Gbit. I was fascinated with that stuff, but the vendor had their folks do all the alignment and installation. So, I didn't get to work with it much. I wonder if you've seen faster speeds than that. I also wonder what the power levels look like for those lasers and what distances the really serious ones can reach. Can they still work in bad weather? It seemed like the ones that I mentioned, still worked in the rain. -Swift PS: It was the May 1984 National Geographic cover that blew me away and made me forever respect holography. :-)
RE: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
In my day job I work on computational holography and other forms of esoteric 3D displays, so I can give you some insight in how these things work. Remember these are vector displays and not raster displays, so the computational side is not an issue. You are basically looking at a pair of D/A convertors that are driven by a pair of parallel ports. The circuit is probably a bit more complicated than that, but you get the idea. This can be done interactively with no problem. With a modern CPU you are probably looking at less than 1% of the CPU time. The complication occurs with the lasers and the optics. For an outdoor display you need a very high power laser, which will literally melt standard optics devices. There are special lens and mirrors that are used with high power lasers, look at Edmund Optics. The deflection range is relatively small, around 1 degree. The limiting factor is how fast you can move the mirror, which depends on mass and inertia. With these small deflections you can get pretty high rates. Indoors with low light you can get away with much lower power, 10mW is more than enough. With this power level you can use standard optics, and the lasers are quite cheap < $30 as long as you like red. I've heard of people using TI DMDs to deflect laser beams. Even the low end DMDs can display 1 bit raster images at 4000Hz. One of the problems with this technology is it's hard to modulate the laser intensity, which greatly restricts the range of colours you can produce. -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mouse Sent: July 19, 2016 4:47 PM To: cctalk@classiccmp.org Subject: Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now)) >> You'd probably know, then - what's the fastest way to deflect a laser >> beam? In particular, I'm wondering how practical it might be to take >> a laser and turn it into a vector display on a handy blank wall [...] > What bandwidth (deflection rate) do you need? Full scale in a > microsecond? In 10 microseconds? Well, if it takes longer than 100ms to replot the display, it will flicker visibly, and the more under 100ms the better. In that time I'd like to draw at least a couple hundred lines, though most of them will be short (line length maybe 1-15% of corner-to-corner distance). What kind of radians/second deflection rates this means depends on how far from the wall you put the projector. But, in terms of the bandwidth on the X and Y axis signals? If we say 200 lines at 25 ms replot (I get 20ms frame rate out of the cg6 for displays significantly more complex than that - ie, with the cg6 the actual limitation is the video signal vertical frequency), that's 125us/line. Turning sharp corners is the hard part with mechanical deflectors like mirrors, as it means very high acceleration of the mechanical parts. I haven't done the math to be sure, but, until/unless taught otherwise by testing, I'd feel dubious about clipping the X and Y signal bandwidths at anything lower than ~1MHz. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
>> You'd probably know, then - what's the fastest way to deflect a >> laser beam? In particular, I'm wondering how practical it might be >> to take a laser and turn it into a vector display on a handy blank >> wall [...] > What bandwidth (deflection rate) do you need? Full scale in a > microsecond? In 10 microseconds? Well, if it takes longer than 100ms to replot the display, it will flicker visibly, and the more under 100ms the better. In that time I'd like to draw at least a couple hundred lines, though most of them will be short (line length maybe 1-15% of corner-to-corner distance). What kind of radians/second deflection rates this means depends on how far from the wall you put the projector. But, in terms of the bandwidth on the X and Y axis signals? If we say 200 lines at 25 ms replot (I get 20ms frame rate out of the cg6 for displays significantly more complex than that - ie, with the cg6 the actual limitation is the video signal vertical frequency), that's 125us/line. Turning sharp corners is the hard part with mechanical deflectors like mirrors, as it means very high acceleration of the mechanical parts. I haven't done the math to be sure, but, until/unless taught otherwise by testing, I'd feel dubious about clipping the X and Y signal bandwidths at anything lower than ~1MHz. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On 7/19/2016 1:22 PM, Noel Chiappa wrote: Those have been around for decades - I recall seeing them used to draw things on the sides of building,_many_ moons ago. I know that the pen motors from Brush recorders were used eons ago. They have frequency response that is very high, and if you had the power to drive them would move very quickly. Also Oscilligraph motors could be used, and already had mirrors mounted on the end. Piezo actuators could be mounted on the Brush motors and swung for a second degree of motion as well. These were in use in the 70's if not earlier. Thanks Jim Gould Brush example: GOULD-BRUSH-220-Strip-Chart-Recorder-Model-15-6327-57-POWERS-ON-SEE-DETAILS http://www.ebay.com/itm/262507072142 Oscillograph: HONEYWELL-1406-VISICORDER-OSCILLOGRAPH http://www.ebay.com/itm/272248210671
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
>> I'm wondering how practical it might be to take a laser and turn it >> into a vector display on a handy blank wall > Those have been around for decades - I recall seeing them used to > draw things on the sides of building, _many_ moons ago. Yeah, me too, but my impression is that they're only for pre-prepared displays, and only some displays (notably those that don't involve the beam turning any sharp corners, such as Lissajous figures). My impression may, of course, have been - be - incorrect, which is what I'm asking for; if you've seen such displays involving sharp-corner turns of the beam and run-time chosen displays, then obviously my impression is incorrect and the technology exists. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
> From: Mouse > I'm wondering how practical it might be to take a laser and turn it > into a vector display on a handy blank wall Those have been around for decades - I recall seeing them used to draw things on the sides of building, _many_ moons ago. I'm assuming they bounce the beam off a mirror, and actuate the mirror, but I don't actually know how they worked. Noel
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
> On Jul 19, 2016, at 4:02 PM, Mouse wrote: > >>> Light show hobby. > > You'd probably know, then - what's the fastest way to deflect a laser > beam? In particular, I'm wondering how practical it might be to take a > laser and turn it into a vector display on a handy blank wall - but > that requires some very fast acceleration of the spot, probably faster > than mechanical deflection can support (though if I'm wrong I'd love to > know it). For example, does piezoelectricity make a crystal distort > enough to use it as an optical deflection element in such a scheme? > (My guess is no, but I don't actually know.) > > I have SPARCstations with cg6s that I can use as vector displays, but > they are vectors converted to raster. I'd like to do real vector - a > parallel port driving a couple of moderately fast D->A converters might > be able to do it; it might take something better, dunno. But without > the deflection mechanism there's no point in even trying to design the > rest of it. What bandwidth (deflection rate) do you need? Full scale in a microsecond? In 10 microseconds? Piezoelectric loudspeakers work up into ultrasonic range. A mirror attached to such an actuator would give you variable deflection. So 10 microseconds might be doable. A faster (no moving parts) scheme might be to use Kerr cells. I don't know if that has been done, but from what I understand about the Kerr effect it seems plausible that it could be. paul
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
On Tue, 19 Jul 2016, Mouse wrote: > You'd probably know, then - what's the fastest way to deflect a laser > beam? Whoa. Interesting problem since a photon carries no charge and thus you can't horizontally or vertically deflect it with a magnetic field. I guess that's why folks make things like these: http://www.newson.be/rhothor.htm > In particular, I'm wondering how practical it might be to take a laser > and turn it into a vector display on a handy blank wall - but that > requires some very fast acceleration of the spot, probably faster than > mechanical deflection can support (though if I'm wrong I'd love to know > it). I wonder how laser projectors work. The must use some kind of internal screen like the ones that use "lamps". I'm guessing they just use lasers instead of lamps to get a brightness and longevity boost. > For example, does piezoelectricity make a crystal distort enough to use > it as an optical deflection element in such a scheme? (My guess is no, > but I don't actually know.) I found mention of something like that in this paper: http://www.sciencedirect.com/science/article/pii/S1875389214002351 It's in the references: F. Filhol, E. Defay, C. Divoux, C. Zinck, M.-T. Delaye Resonant micro-mirror excited by a thin-film piezoelectric actuator for fast optical beam scanning That sounds wicked-cool, by the way. If you ever do build something like that, please share some video! -Swift
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
They generaly use mirrors - I would cobble something together by taking the laser diode read head from a CD rom, and removing the diode assembly, and glue a small, thin, front surface mirror in its place, and drive the coil from the output of an audio amp, just to try it out. A pair of these, at right angles, would give you X/Y deflection. Karl - Original Message - From: "Mouse" To: Sent: Tuesday, July 19, 2016 4:02 PM Subject: Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now)) Light show hobby. You'd probably know, then - what's the fastest way to deflect a laser beam? In particular, I'm wondering how practical it might be to take a laser and turn it into a vector display on a handy blank wall - but that requires some very fast acceleration of the spot, probably faster than mechanical deflection can support (though if I'm wrong I'd love to know it). For example, does piezoelectricity make a crystal distort enough to use it as an optical deflection element in such a scheme? (My guess is no, but I don't actually know.) I have SPARCstations with cg6s that I can use as vector displays, but they are vectors converted to raster. I'd like to do real vector - a parallel port driving a couple of moderately fast D->A converters might be able to do it; it might take something better, dunno. But without the deflection mechanism there's no point in even trying to design the rest of it. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))
>> Light show hobby. You'd probably know, then - what's the fastest way to deflect a laser beam? In particular, I'm wondering how practical it might be to take a laser and turn it into a vector display on a handy blank wall - but that requires some very fast acceleration of the spot, probably faster than mechanical deflection can support (though if I'm wrong I'd love to know it). For example, does piezoelectricity make a crystal distort enough to use it as an optical deflection element in such a scheme? (My guess is no, but I don't actually know.) I have SPARCstations with cg6s that I can use as vector displays, but they are vectors converted to raster. I'd like to do real vector - a parallel port driving a couple of moderately fast D->A converters might be able to do it; it might take something better, dunno. But without the deflection mechanism there's no point in even trying to design the rest of it. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
