Laser light show features full XY control via homemade galvanometers

laser_light_show

[Rich] over at NothingLabs has put together a really cool laser light show that you really must see in an effort to win a laser cutter from Instructables.

His walkthrough discusses the mechanics of laser light shows – specifically how galvanometers are typically used to precisely aim mirrors in order to draw images and write text. Commercial galvanometers tend to be pretty expensive, so he opted to build his own, using relatively cheap and easy to find parts.

The galvanometers were constructed using a pair of old speaker woofers, a few Lego bricks, and some acrylic mirror squares. The mirrors were mounted on the speakers, which were then wired to an Arduino. He removed the batteries from a cheap red laser pointer and permanently wired it to the Arduino, which it now uses as a pulsed power source. Once he had everything built, he positioned the laser using a fog machine for guidance.

As you can see in the video below, the laser show is quite impressive. His homemade galvos provide a somewhat rough quality to the final projected image, and we like that a lot. It looks almost as if all of the text and images were hand drawn, which is a pretty cool effect.

Just as [Rich] mentions, we hope to see some cool hacks based off his work in the future.

If you are interested in some of our previous laser features, check these out.

Comments

  1. ferdie says:

    cool but can be fake
    you see the laser setup
    than it cuts to the wall and you see never
    the setup and the laser the same time
    make a video that shows the the laser and projection the same time

  2. jordan says:

    I have been working on a similar thing for a while and it’s cool to see that implementation working.

    This person’s project might be reason enough for me to order a development board and try it my own way…

  3. other jordan says:

    I’ve been working on a very similar project too, but full color (RGB).

    @ferdie, why do you think it’s fake? The principles used are the same as those used in professional laser shows. The equipment is just cheaper. Using speakers are commonly used to create cheap DIY galvonometers. http://www.acm.uiuc.edu/iCal/projects/laserline/

  4. Erik Johnson says:

    I’ve been wanting to do the “speaker” galvo method for a while, there no reason they can’t keep up if you keep the weight down (My imagined method would use mylar made rigid with maybe cardstock for the mirror on the center of the cone, pivoted on a toothpick or thin strong rod of some sort to the edge). the rest is just calibrating analog out from your source to the speakers

  5. J Harton says:

    @ferdie While a valid point, I must question the motive of someone making going to the effort of faking a movie and including the obvious effects of their setup (some shake and flicker) and linking to their website. Further the static still picture of the whole thing with the laser on and showing where there appears to be mist and other details being expelled seems much harder to fake.

  6. Stevie says:

    I’m not sure that I get it.

    Two speakers with mirrors attached. In order to move a mirror, he plays audio through the speaker which causes the cone to move and in turn, the mirror. Is that right?

  7. MrX says:

    @Stevie
    A speaker is just a device that converts voltage deltas into tiny displacement deltas. That’s exactly what you need for a galvo.

    For better results one could even remove the speakers diaphragm and replace it with a light mirror.

  8. hubert says:

    Hello, if this really works and I believe it does, cool. I have built a system like this years ago, but with parallel port D/A on an old Laptop. As Software either http://patrick.kolla.de/heathcliff.html or http://scifi.pages.at/kleiner-onkel/rf_popelscan.html. but i never got the right speed. Seems you have a lot of inertia, so your speed would also not be very high. Better results can be made misusing some tiny steppers as galvos.
    Some cool experiments and tipps you can find http://spt06.chez-alice.fr/00/lasers.htm this is not my site ha has onlythe same name as my nick

  9. Tom the Brat says:

    Too cool.

    I used to do this in the late 70’s with a setup about like this, but I had to borrow the High School Physics department’s laser and two “wavetecs” from the Junior College electronics department.

  10. Hanna says:

    The Lord of self-made galvos surely is Mr. Chan:

    http://elm-chan.org/works/vlp/report_e.html

    (wiffout Arduino. How can that be possible? :))

  11. hubert says:

    Hanna, I fully agree to you, but I failed to rebuild the galvos of Mr. Chan esp. the feedback, so I decided to build open loop galvos with steppermotors, the hardest part was to find the right steppers. I´ve got the my best results with those out of used CD-Rom drives. But that was very long ago. The computer used was an ATARI ST, at that time there was no arduino, lol.

  12. echodelta says:

    Toothpicks! This is a bar or bistro hack. Light gauge piano wire under tension, is a better axle for the pivot.
    How about tiny motors used as galvos, limited angle spring or voltage centered. Vibrator phone sized motors would have low mass. The brushes can be bypassed with speaker flex wires to armature spots directly. I have not tried this, but I have hacked head motors from hard drives for laser display.

  13. gcat122 says:

    Really fun and pretty good looking for open loop. Some of the distortion may go away if the mirror pivot support is moved away from the center by the length of the mirror and a small post is attached to the center of the cone. The edge of the mirror that was glued to the speaker cone at an odd angle would now be attached to the top of the post where it is parallel to the speaker face and in line with the vertical movement of the center of the speaker. Fewer odd angle strains involved.

    I played with mirrors, speakers, and a helium-neon laser in 1969 but there was no HAD to post to. Gotta build this!

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