Phased array ultrasonics[0] and Multibeam echo sounding[1] has been around for decades[2]. This project in particular is an example of what's called an air coupled ultrasonic phased array. It's an interesting project, but it's not first. Congrats on making it happen though, and thanks for the write up.
[0] https://en.wikipedia.org/wiki/Phased_array_ultrasonics
Have you seen the way lasers are used to do this? NDT or non destructive testing has use dual laser systems to create ultrasound for several decades. Check it out if you are interested.
I can try to find that papers if you would like.
Fascinating! Awesome project. Interference of waves seems to be such a fertile ground for all sorts of unexpected powerful possibilities.
There have been some projects to make “sonic cameras” using MEMS mic arrays that this reminds me of. https://hackaday.com/2020/08/10/acoustic-camera-uses-many-ma...
> If it's so easy, why hasn't anyone done it before?
Medical 3D ultrasounds are a thing:
https://en.wikipedia.org/wiki/3D_ultrasound
That doesn't take away anything from how cool this project is though!
Not sure about the first, but it is really cool regardless. I tried doing a similar thing once upon a time with RFID (SAR), but I couldn’t figure out how it would work.
This seems even lower level, since I was basically using off the shelf components, and you built the whole thing yourself!
Really cool.
well, you sir, are the first. except maybe those lamers: https://en.wikipedia.org/wiki/Medical_ultrasound
:)
Amazing. I was literally working in a factory at that age
Reminds me of phased array radars. Where they form an array of transmitters into a moveable “beam”
https://en.m.wikipedia.org/wiki/Phased_array
Radar is at its simplistic sensing a pulse out and listening for a return. But then the engineers wanted more.. of course home radar would not be really safe.
Cool project by the way.
Hah! Back in my undergrad days I’ve thought about doing exactly this, but I couldn’t figure out the beamforming part, so I just measured distances in (microcontroller) software by correlating transmitted x received waveforms.
Awesome project! I’m happy the author figured it out! I feel vindicated :)
> I hated using a Chinese company for a job that could be done in France, but no local companies were offering the same service.
They exist, except they are more pricey.
Interesting, but yeah, he fought way too hard with the analog part driving the transducers
I get it, it's a hobby project, but I feel the knowledge of analog electronics is getting lost in a way (and yes the analog people are the worse at explaining things - I think I saw YT videos more informative than whole university courses)
Great accomplishment, but people were building 3D ultrasonic scanners back in 80-ies, for much less than $100:
[didn't read your article, your claim has put me off, sorry]
-- use an electric spark gap as the wideband acoustic source
-- use 3 simple electret mikes on 3 axes. Mikes don't need to be high quality (spark intensity can always be raised as necessary), so they were hand-assembled using metallised mylar film (used nowadays to pack some food, or ESD-sensitive electronics components).
The rest was data processing.