You can hear sound, of course, but what if you could see it with a laser? That’s what [Goosetopherson] thought about, and thus a new project that you can see in the video below was born.
The heart of the project is an I2S chip and an ESP32. Sound energy deforms a plastic film that causes a mirror to move. The moving mirror alters the course of the laser’s beam.
An important part of the project is the 3D printed enclosure designed in Fusion. Some wires are routed through during printing, and there are heat-set inserts.
If you haven’t run into it before, you can think of I2S as I2C for stereo audio. It uses a synchronous protocol to push audio data using three wires. The board in question takes the digital data and decodes it to drive the speaker.
This is a simple project that would lend itself to lots of substitutions if you decide to replicate it. In fact, we’ve seen a version of this that is nothing more than a Bluetooth speaker, some plastic film, a mirror, and a laser.
This (with an ultraviolet laser to be undetectable) is what is used to eavesdrop on officces across the street vy secret services.
Invisible, not undetectable.
Well, if you’re going to nitpick, it’s not invisible either, depending on your optics.
Exactly. If it was “undetectable,” then it would be pointless, cuz they couldn’t measure it!
As far a being invisible, the term is generally used to mean “by the naked eye.” Of course it would be visible with specialized optics! That’s what they use in their “bug.” (The surveillance equip.)
Infrared, not ultraviolet. Ultraviolet sources are more difficult to produce and cost more than infrared sources.
Ultraviolet is also trivially easy to detect: hold up a piece of plain white letter paper. The brighteners in paper fluoresce brightly when struck by UV light.
as someone who just recently looked at one, they seems to start around $8k.
that project will need to wait another 30-50 years…
“you can think of I2S as I2C for stereo audio”
the only similarity I2S and I2C share besides the characters in their name is that they move data over wires.
While the two are very different in architecture, they share more similarities:
Both have Philips Semiconder DNA in their origin, both were designed for short distance Inter IC (hence the I2 in both names) and both are based on a Synchronous Master/Slave Architecture.
Or you could bypass all of that and just glue one edge of a mirror to a speaker. KISS.
Oh if you played KISS the mirror would fall off.
That doesn’t really visualize the tone, it just wiggles the laser around. It needs a rotating prism to sweep the laser from left to right and a galvo to move the beam up and down with the audio signal.
When I saw the headline it immediately made me think of the Spencer’s gift light show I had when I was a kid… I actually just sold it finally on the big auction site because it was just collecting dust…. Laser FX by Design in Mind. This isn’t my listing but it has much better pictures… https://ebay.us/m/qFIV7O
Yeah I had to watch it again to make sure. I mean it’s cool but it’s basically a very fancy… er…. vibrating instrument making a beam shimmy. Now if you want to see something cool with a laser, watch what Hirosawa Susumu does. Sure, it’s probably just MIDI triggers being fired when he breaks a beam, but way more entertaining.
https://www.youtube.com/watch?v=-et_5qY46rQ
Edmund produced these as “MusicVision” in the late 1960s – unfortunately, both lasers and useful lightweight mirrors were essentially unavailable for we scrapheap kids, but it was fun to play with. We had ideas about building modulated lasers with the idea but had neither the budget nor the experience to put it all together at that point.
Alternative (still cheap) approach might be to use two mirrors, one fixed on a pivot point and another copy on another speaker rotated 90 degrees. then bounce the laser from one to the other placed nearby. That way you have x and y or stereo sound inputs.
You need to amplify the movements though, maybe by increasing the length of the path with prisms/mirrors (you don’t want to increase the sound level, it will make you mad and blow the speakers).