[sci.electronics] Laser show controllers

Ed_Meyer@mindlink.bc.ca (Ed Meyer) (06/15/91)

> tedwards@aplcomm.JHUAPL.EDU writes:
> 
> Msg-ID: <447@aplcomm.JHUAPL.EDU>
> Posted: 14 Jun 91 18:09:06 GMT
> 
> Org.  : JHU/APL, Laurel, MD
> Person: Edwards Thomas G S1A x8297
> 
> In article <12530@qisoff.phx.mcd.mot.com> hbg6@citek.UUCP (John Schuch)
> writes:
> >In article <kWhnZkR@quack.sac.ca.us> 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.
> >You are looking for galvomotors. They are basicly a high horse-power
> >meter movement. Meridith Instruments in Phoenix sells used ones for
> 
> There is a book called _The Laser Cookbook_ which describes some circuits
> for driving galvos (usually just a 741 driving a complimentary pair of
> medium-power transistors).
> 
> For those of you designing a laser show, I reccommend the AD7226 quad
> 8-bit D/A converter.  It saves you from having to have a large number of
> D/A chips, opamps, and latches since it has all of that built in.
> (i.e. voltage mode D/A).
> 
> -Tom

Or, if my information source is correct, you can do what the fellow did to
control the audio-&-laser show for the old expo'86 shows in Vancouver.
Apparently he used the D-to-A stereo drive DAC output from a stock Amiga.  If
my info is correct, the Amiga ran the whole audio-visual show.

my $.02 worth

        Ed Meyer

tedwards@aplcomm.JHUAPL.EDU (Edwards Thomas G S1A x8297) (06/18/91)

In article <6287@mindlink.bc.ca> Ed_Meyer@mindlink.bc.ca (Ed Meyer) writes:
>control the audio-&-laser show for the old expo'86 shows in Vancouver.
>Apparently he used the D-to-A stereo drive DAC output from a stock Amiga.  If
>my info is correct, the Amiga ran the whole audio-visual show.

Hmmm...if you mean utilize the waveform shaping ability of the Amiga
stereo sound system?  It's possible, although I'm sure there are filters
which will limit the frequency of the system to audio freqs (i.e. no 50-100 hz).

Actually I have tried using my Amiga to drive galvos before, but I used
a conventional portable stereo box, which probably had even more filtering than
the Amiga itself had.  I could not get useful results from waveform
shaping in general, although the sinewaves could be skewed just a little
bit if one tried to use a square wave.

-Tom