How I built the world's first 3D ultrasonic scanner
In this technical retrospective (2021), @belzebalex shares practical architectural lessons learned from running, scaling, or migrating production software under lean constraints.
Core Principles for Independent Builders:
Defaulting to simpler architectures (such as monolithic frameworks, SQLite, or managed VPS) prevents early engineering bankruptcy.
Evaluating true compute and egress costs reveals that high cloud bills can often be slashed by 80%+ through judicious re-platforming.
Code you write at 2 AM as a solo engineer must be easy to debug six months later without complex microservice dependencies.
Community Debate Themes:
HN engineers debated the tradeoffs between cloud convenience and raw server economics, database indexing strategies, and resisting premature architectural complexity.
CATEGORY Frugal Engineering →
HISTORICAL ERA Pandemic Bubble (2020–2022)
COMMUNITY SCORE ★ 152 points
TOTAL DISCUSSIONS 44 comments
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
[1] https://en.wikipedia.org/wiki/Multibeam_echosounder
[2] https://patents.google.com/patent/US5675552
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.
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.
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!
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)