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Thread: electrically tunable lenses and dual axis mirror (Optotune)

  1. #11
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    I think you can drill out the center of a small speaker and then remove the paper cover on the coil. If you carefully glue the lens in that spot and align it well, then you can exploit the coil as a linear actuator BUT it will ring. You might have to impress a dc voltage on the coil to keep it somewhat stiff. Then place the coil in a PID loop like a galvo. Now you have to worry about heating the coil. You can make your own by edge winding a coil on the lens and suspending it in a magnetic field or the other way around with a ring magnet but that adds weight. PWM would be a second way to do it and eliminates the dc resistance heating issue.

    If you add this to a fixed lens you can get a lot of the capability of the so called liquid lens. You should be able to get with small lens size a khz or two response with 2-3mm travel distance. Not much but enough for subtle effects. Cost should be your time and a few dollars. Guess you could cascade these for some more varied changes. Most of all have fun.

  2. #12
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    Those mirrors cost a whopping $3600 (2000 for the mirros and 1600 for the controller board). I doubt for a bulk order it could drop to sub 200$ range.

    Maybe an easier approach would be good old cheap chinese galvos. Those Optotune mirrors go at most 10Hz on each axis. If the galvos were running that slow I bet you could put huge mirrors on them and they would still work fine. But someone correct me if I'm wrong.

    To me limiting factor for the galvo approach is the large PCB (amp) and requirement for 24V DC while everything else in my system is 12. Any chance for very slow scan speeds we could feed the amps 12V instead?

    Kecked, for your lumia project I think the easiest approach for focusing lens is cheap RC servo motor and some laser cut acrylic linear actuator.

  3. #13
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    https://www.digikey.com/product-deta...2477-ND/920437

    I’m using a speaker with a paid feedback loop. Linearity is ok for what I need but not the best. For my toy it’s fine.

  4. #14
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    Quote Originally Posted by kecked View Post
    https://www.digikey.com/product-detail/en/tdk-lambda-americas-inc/CC3-2412SF-E/445-2477-ND/920437
    The scanner AC to DC PSUs are pretty big, I'm surprised it works with such a small 250mA DC to DC converter.
    That said this takes 24V and outputs to 12, while I need the other way around.

    it's a bummer the dual axis gyroscope based mirror is so expensive, because while galvo scanner option might work fine it's pretty bulky. Is there a MEMS option by any chance?

  5. #15
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    Quote Originally Posted by Yerkat View Post
    Those mirrors cost a whopping $3600 (2000 for the mirros and 1600 for the controller board).
    Man that's pricey. I fail to see any practical application at that price-point. You could buy a couple sets of Saturn 9's for that and get much broader/better performance.
    "Help, help, I'm being repressed!"

  6. #16
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    http://modulatedlight.org/optical_co...cal_index.html

    I forgot about this. I was going to try something similar. Turned out leds were a better option with fresnel lens. Never got around to trying it. Seems over distance the laser mode hoping is a problem and leds don’t have the issue. A tight beam is actually not desirable at those distances as aligning is nearly impossible and with air movement the beam will move around feet.

  7. #17
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    The Optotune EL-3-10 liquid lens costs 125 USD.

    Here's a $35 way to get Varioptic liquid lens, without driver of course.
    https://www.youtube.com/watch?v=zvMv6WiWMHA
    You're welcome.

    But there must be other cheap products out there we could scavenge liquid lenses from. Any ideas? There are many autofocus webcams but no easy way to tell if it uses mechanical autofocus or liquid lens without wasting money to buy and disassemble.
    Probably there are other products with bigger apertures that might be using liquid lenses too.
    Give me some ideas here, people.
    I got a .45 inch DLP chip mini projector I'd like to put one in personally.

  8. #18
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    Ledex makes a line of "soft shift solenoids" that move the armature in a linear path proportional to drive current. They're not all that small, or fast, but they could drive a gymbal mount.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  9. #19
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    Allow me to add another 2d mirror to the menu as this one is ahrder to find, http://mirrorcletech.com/devices.html .
    5mm sounds pretty good for laser projectors, angle sucks though at 6° to +6° mechanical.

  10. #20
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    I think this was discussed before but is it possible to Mirror after the scanner to expand the scan angle like the pangolin disco scan thing. My fear is it would diverge the beam at the same time.

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