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Thread: Variable 5VAC galvo driver circuit?

  1. #1
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    Question Variable 5VAC galvo driver circuit?

    I have a "Skyman" galvo "system" (basically a GM-20 type galvo with a mount and 1/4" audio jack) that recommends using a 5VAC, 1 amp power supply along with a potentiometer for driving the galvo and mirror positioning across its full range. I would like to be able to use a variable 1-5VDC or 1-10VDC voltage (from a DMX decoder board I already have) along with a driver circuit to accomplish the same task, in lieu of using the manually-adjusted potentiometer.

    Any recommendations on a specific circuit and components that might work for this application?

    Thanks!
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

  2. #2
    mixedgas's Avatar
    mixedgas is online now Creaky Old Award Winning Bastard Technologist
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    A skyman is a RM4 actuator or GM20 or G330 Galvo from the pictures I've seen. You could use a variac driving a step down transformer, but it would not be compact. A LM3886 amplifer costs 6$ for the chip and needs 10$ more worth of parts. A 12V or 24 VDC power supply would be cheaper, and you could go down as low as 5 hz, getting more effect for your buck. Adding a additional 12V psu would get you down to DC. A simple 10$ or so kit sine wave generator board would drive the galvo, giving you varying amplitude and frequency, or the addition of a sound card system such as laserboy or norms would give you some beam effects, albiet limited to 110 hz or so, but at a very wide angle.

    PM me and I'll see what I can do for you when I get home, as I have several open loop amp boards that could go cheap and have damping, and I need contributions to the pango update fund.

    of course any audio simple amplifier for boosting a walkman may do what you want it to do. But it needs some beef to it as your looking at 12/7 = 1.7 * 1.141 = 2.4 or so amps RMS which works out to a 20-30 watt amplifier. LM3886 can do that



    want another rm4 and have dual axis ? I've got a lot of open loop :-)

    Steve
    Last edited by mixedgas; 09-16-2008 at 07:01. Reason: ADDED MATH

  3. #3
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    Thanks for the info - I'll probably give an audio amp circuit a try, since I really don't want to dump too much $ into this, as this is just a "backup" until I get my scanners repaired!

    Since making my original post, I found the instruction sheet for the Skyman, and it actually shows a bipolar 5VDC suppy as the driver, with a 50 ohm rheostat to control static beam positioning.

    Looks like it's time to do some tinkering...
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

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