DIY open-source ultrasound hardware on the rp2040/rp2350

As someone who has never had an opportunity to play with it, I’m fascinated by what people are doing with PIO. In many cases it seems to be a ‘good enough’ FPGA on absurdly cheap hardware.

So... paired with https://coe.gatech.edu/news/2026/04/batteries-not-included-o...

and one has a complete hardware solution?