Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!netcomsv!gandrews From: gandrews@netcom.COM (Greg Andrews) Newsgroups: sci.electronics Subject: Re: Laser show controllers? Summary: Possibilities Message-ID: <1991Jun9.071244.1962@netcom.COM> Date: 9 Jun 91 07:12:44 GMT References: Organization: Netcom - Online Communication Services UNIX System {408 241-9760 guest} Lines: 31 In article mrapple@quack.sac.ca.us (Nick Sayer) writes: >Let's say I was crazy enough to want to design and build a lazer-show >controller. > >It's obvious that you use a pair of mirrors - one to shift the beam >along the X axis, one to shift the beam along the Y axis. Fine. >But those shows achieve fast shifting around. So they must have >very fast, yet precise motors. > The REAL ones ($$$) use something my buddy calls "Analog Servomotors", which I think means "a beefed-up galvanometer". The drive rotates a shaft to turn the mirror. It reduces parallax in the mirror's movement over hinged-on-one-side techniques. If you're not overly concerned with large amounts of deflection, then you can use audio speakers (as another posting mentioned). They are reasonably linear through the central 10-20 degrees of deflection, and are cheap enough that failed experiments won't break the budget. Another possibility might be the head positioner mechanisms from hard disk drives. Obviously, voice coil types would be preferred over the stepper motor ones. (Guess what technology the "voice coil" drive was borrowed from!) -- .------------------------------------------------------------------------. | Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | | | Internet: gandrews@netcom.COM | `------------------------------------------------------------------------'