The Prism: Laser Synth-Guitar

This is an interesting instrument. Part laser harp, part guitar, the Prism seems to have some potential. [Jeff-o] put some major time and effort into refinishing a guitar, building the circuit and putting it all together. He did a great job, the instrument looks fantastic and appears to work. We do have a request though; please post a video of it being played as an instrument. So many of these electronic instrument projects just spit out random noises. While we understand that some people are into that, we would love to hear some control. How about intentionally changing notes to make a melody? Based on the description, it should have control for pitch, and even speed of the oscillation. So let’s hear some music. We don’t care if you’re any good, just please play some music with it. If you would like to build your own, he has the schematics and PCB layout available for download.


  1. TheKhakinator says:

    Thank you! Cool post and yes I am also so fucking sick of those goddamn projects “oh look at me complicated synthamabob with a million wires and it sounds like a dead hard drive on ecstasy”.

  2. jeff-o says:

    More videos and sound clips are on the way, either late tonight or tomorrow! Thanks for featuring my project on your blog!

  3. Caleb Kraft says:

    feel free to link to a vid here, but be aware that if you put more than one link in a comment, the spam system will hold it for approval.
    Cool project, let’s hear some music!

  4. uncivlengr says:

    There are a few videos on youtube of the project; hackaday could have easily picked the video that moreso demonstrates the project as an instrument than as a noisemaker for an infant.

  5. Caleb Kraft says:

    That video is much better. I must have overlooked it. I’d still love to hear a song.

  6. MrX says:

    GOD, I hate kids.

  7. proc says:

    @MrX: too bad your parents didn’t have the same feeling toward kids

  8. Alchemyguy says:

    Ha, Burn.

    I have even less constructive material to add than mrx.

  9. sunjester says:

    I’d love to hear a song as well. Children can be cute but c’mon, maybe some serious demo action?

    Also… what if they were dvd lasers? thats half a lightsabre yea?

  10. TMH says:

    @uncivlengr: That’s much better. You can really hear the potential of it being an instrument in that one.

    @jeff-O: POST THE VIDS SOON! We wanna hear you rock on your kick ass toy!

  11. noises says:

    hey there’s nothing wrong with just making noises and not everything has to be a bastardized techno guitar. transcend your inborn pragmatism for a minute and try to appreciate this creation.

  12. concino says:

    Am I the only one thinks that this is not a child-safe project? Why the heck that kid is exposed to lasers that can seriously damage his/her sight? Even though beams are directed parallel to the guitar’s plane, once the beam is cut, the reflection on the white backdrop and the eye’s focusing ability can make this harmful to the eye. I don’t hate kids but I hate dumbass parents.

  13. TMH says:

    concino, you keep your kids locked up in a basement with no lights, no TV and helmets on their heads…. don’t you? lol

    Overprotective much?

  14. thatdude says:

    sounds like my old dial-up internet…..

  15. jeff-o says:

    Hey everyone, fresh videos are up. Last night I filmed some basic frequency sweeps, some effects demos, and myself actually trying to play it. I’m not at the point where I can play “Smoke on the Water” just yet, though!

    Here’s the music demo:

    Visit the original Instructable (or my YouTube page) for the other demos.

  16. signal7 says:

    even I have to admit I skip any post relating to synths because most of them are little more than noise makers. Thanks for putting some perspective on the meaning of synth vs noise maker.

  17. concino says:


    From: “”

    Dennis Robertson, M.D., Mayo Clinic ophthalmologist, conducted investigations with a green laser pointer directed to the retina of a patient’s eye; the eye was scheduled for removal because of a malignancy. The green laser damaged the pigment layer of the retina, although it did not cause a measurable decrease in the visual function of the patient’s eye. Dr. Robertson believes that longer exposures could harm vision, however. He also warns about potential damage from higher-powered green laser pointers. “With the use of laser pointers that are more powerful than five milliwatts, there would likely be damage to the actual vision,” he says. “Functional damage could occur within seconds.”

  18. Ninja says:

    Somebody cut that kids hands off.

  19. i circuit bend like crazy and I’m really passionate about using my instruments as instruments. For example, I add a trimpot and tune all the toy keyboards so when you make them go crazy the knobs can normal back and be on-key. I play several instruments in a rock band and we write it all in there so it’s not a gaudy or overbearing use of the circuit-bent stuff, very tasteful.

    anyhow, I really appreciate and relate to that concept of homemade instruments playing actual melodies and such.

  20. Rex says:

    It’s not very prudent to have children playing with lasers. Nor adults as it shows :P They are looking strait into the laser light reflected by the fingers. Although not as strong as a direct light it still causes some damage to the retina.
    It’s cool but not really 100% safe.

  21. jeff-o says:

    I suppose I should add that the videos really do over-emphasize how bright the lasers are. Since the camera is trying to pull in as much light as possible (I filmed in less than ideal brightness), the laser light appears very bright. In practice, it tends to illuminate your finger but it doesn’t dazzle your eyes or anything.

  22. concino says:

    You cannot assess the damage laser is doing to your eye by assessing if it is dazzling your eye or not. People who work with really powerful lasers can get a hole in their retina in a split second of focusing their eye to the laser beam (even when it is reflected, if the reflection surface is highly reflected and the beam is strong enough) This is painless and you wouldn’t know that you’ve damaged your eye until you realize that there is a spot in your vision that doesn’t go away. Granted a 10mW laser cannot cause this type of damage, but prolonged exposure would cause damage to your retina. This project is using 10mW laser which is way stronger than it needs to be (5mw would’ve been enough). Also even thought it is not as cool, red laser would’ve been much much safer.

    More importantly, when you focus to a bright spot with your eye, even if it is reflected, you are collecting all those beams of light and focusing it on a tiny space on your retina, that is intensifying the power of the laser, and you are doing it in a short distance of 2 feet. Even worse for the kid in the video as he is several inches away from it, and he doesn’t know that he shouldn’t look at a green laser for a prolonged period of time.

  23. jeff-o says:

    Well, I do appreciate your concern. I will probably switch over to red 5mW laser modules soon, since the green laser pointers I used can’t be focused well enough. I had also hoped that the green laser beams would be visible in dim light, but they’re not – not enough, anyway. So, I may as well use red lasers instead even through they’re not as cool.

    In the meantime, only adults are allowed to play the Prism, and my kid will get a different instrument to play. A sequencer, maybe? I have to decide!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 96,679 other followers