Path: utzoo!utgpu!watmath!clyde!bellcore!rutgers!cmcl2!nrl-cmf!ukma!tut.cis.ohio-state.edu!cs.utexas.edu!sm.unisys.com!aero!venera.isi.edu!paris.ics.uci.edu!orion.cf.uci.edu!cbell2 From: cbell2@orion.cf.uci.edu (Chris Bell) Newsgroups: sci.electronics Subject: Re: deflection systems Keywords: General Scanning Galvos Message-ID: <1239@orion.cf.uci.edu> Date: 6 Dec 88 19:32:37 GMT References:<1372@cseg.uucp> Organization: University of California, Irvine Lines: 30 In article hobbit@topaz.rutgers.edu ($ *Hobbit*) writes: >Professional shows use multiple x-y pairs of GS's better positional-feedback >galvos -- they're not only fast as hell, they provide exact feedback about >where they are, and you can build your driver accordingly. They also cost >something like $700 per. Since GS is apparently still the only company >making these things [someone please correct me if I'm wrong] they can get >away with this pricing scheme. > Yes. I do work for a company called LOGIC+ (logic plus) which does portable laser graphics shows. We use GS galvonometers. They are pretty good, but not as good as we would like. All of the feedback in the world won't do you any good if the thing just won't slew fast enough. We have, with our own custom amplifiers, a bandwidth of about 1500hz from these guys. Eventually, we will be adding a digital control feedback control system with a very large power ampilfier to coax more bandwidth. However, even 1500hz does not give you very much bandwidth to scan a vectored x-y image that has a lot of corners. (I mean a picture, not an abstract art work). As a result, we use multiple coordinated scanners. (We do a piece from the Star Wars trench scene that is very busy. 1 scanner gets the trench, 2 others handle Skywalkers x wing and vaders tie.) Fun stuf ;-) Later. Guy ~The Interrupt Master~