DIY sonar scanner (practical experiments)

I worked for a medical ultrasound company in the late 1980s, where we did phased array beam steering with very elaborate FPGAs, DSPs, and only the very highest level processing with general-purpose microprocessors. Staff was dozens and dozens of very talented electrical engineers and programmers. What you've done by yourself with just a contemporary microcontroller is extremely impressive!

Really really nice work!

I don't comment often, but man, after two decades working in cellular wireless data network engineering, this is the best phased array explanation I've ever seen. The visualization you did, the solenoids in water, the pick and place plotting, and the overlay at the end each by themselves were awesome. But showing all three was just amazing. I've tried to explain this to peers on numerous occasions and it's a difficult concept to grasp without seeing it. Very well done.

As a professional programmer, I really love your 'coding' intermissions xD the one with drill and glove was hilarious!

I have to say it. THIS IS YOUR BEST VIDEO EVER. I was kinda getting sad that you didn't upload that frequently anymore, but the wait was well worth it! Hut ab mein Freund :)

That was absolutely outstanding. Incredibly good job! Very cool project

13:48 - "Let me display the sonar as an overlay": Blew my mind. I understood how it works. Tks

If you have taught yourself about phased arrays and gone on to develop this experiment without help from anyone else then I truly admire you. This is brilliant work. 👏🏽

Wow, you visualizations are top-notch! The best visualization I've seen on the subject, and mostly practical too!

Holy production quality batman! Good job and it was real fun watching you toil over this project on livestream.

Your effort in making this, from the device design itself to the video filming/editing is OUTSTANDING!

Same technology used at the lab where I worked 50 years ago to steer seismic arrays, spread out over hundreds of miles, to locate earthquakes. Obviously can't pick up seismometers and move them about, but phased array math does it just fine. Good collaboration of geophysicists and electrical engineers.

Very cool! You can actually use alternating scan rates to see further than your sample rate. Assuming you are scanning/listening constantly (so you transmit a pulse, wait to receive for t time then transmit again exactly when that time is over) you are actually seeing distant items in your near field as their echoes are still returning to your receiver (2t period). The only time you cannot hear them is during the transmit period. If you alter the scan rate, you can cohere them together (only the coherent signals will add up) over time and extend your physical scan distance. The different transmit rates are effectively a distance phase.

this is legitimately the coolest DIY project I've ever seen. I've seen the videos of the little Arduino sonar projects that rotate back and forth like old fashioned radars, but to see a demonstration of a modern phased array radar using the same method is absolutely amazing.

I helped remove the sonar transducers from USS Fox CG 39 during an overhaul in '89. It took two men to lift them. They were covered in sharp cooling fins and there was no good way to hold them. We had to carry them up six decks of ladders, the length of the ship to the quarterdeck and down the gangplank to a truck.

I'm a medical ultrasound researcher, and this is a really good primer on beamformation theory without digging into the math. Though in medical ultrasound "phased array" means an array with at most half wavelength spacing, I understand radar guys are a bit more liberal with the usage. Still, it's important to know that this is just the tip of the iceberg. This is just fixed transmit steering for narrowband signals in the far field with fixed weights. Dynamic nearfield focusing of broadband signals in both transmission and reception is standard operating procedure these days, and there is a ton of nuance in optimizing the parameters. Also, your main sidelobe bottleneck here is your grating lobes, which are the result of the transducer spacing. Those cannot be easily tuned on the fly, and thus are critical hardware considerations for the array designer. The other side lobes can be tuned by adjusting the weights before summation, which we US folks call apodization. Still this is pretty impressive for doing this on the cheap side of things. Would love to build something like this myself.

As an aircraft avoincs apprentice in the 70's I worked on weather radar systems that had multi KW magnetrons, physical wave guides and mechanical dishes that swept an arc. At that time the new tech stuff was coming in with phased slot arrays, gunn diodes and digital signal processing. Absolutely mind blowing shift in tech. Got a lot of redundant really strong magnets out of it though.

Long time ago, I tried to build something similar- the biggest issue with doing a phased array like this is the sidelobes. You really need some small transducers- if memory serves (without my handy copy of Skolnik's Radar handbook nearby), best spacing is about 0.7 of the wavelength. without that kind of spacing, the sidelobes (things outside the 60 degree sweep) have nearly as big a return as the objects within the sweep. Your simulation seems to show this? What may get you even better resolution is a Synthetic aperture setup (SAR, or sidescan sonar) Cool thing about SAR is that you can do it with an FFT. At 40KHz, you need about 5mm spacing. Way smaller than any transducers I could source at the time (25ish years ago). Mind you, I did this with a PIC16C71 (UV Eraseable!) that has 288 BYTES of RAM and an 8 bit A/D converter, and all in assembly! You can do a variant with a "zig-zag" of the transducers so at least in the far field, the spacing is pretty close and you can reduce the sidelobes. Worked on it for a bit but... LOOK A SQUIRREL!

Finally someone with a local pcb manufacturer as sponsor instead of a chinese one.

This just blew my mind. Everything about it. The Presentation, examples, explanation, shots, editing, and method used to impart understanding on this topic are just… It’s just art at this level. also… The rolling pin got me.