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Do you do any simple experiments? Or track things and analyse them? (lemmy.sdf.org)

submitted 3 weeks ago* (last edited 3 weeks ago) by Achyu@lemmy.sdf.org to c/asklemmy@lemmy.ml

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Recently downloaded the phyphox from F-Droid and thought about this while thinking about what all stuff I could do with it.

Are there any online resources about such stuff?

What all things have you(or people you know, in your locality etc) done along that line?
And not only big thigs, if you're tracking other stuff, please do share your experience on that too.

Edit:
Sharing the github page of the app too:
https://github.com/phyphox/phyphox-android

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[–] pancake@lemmygrad.ml 5 points 3 weeks ago (2 children)

Of course!

I wanted to test whether a cheap piezo buzzer could be used as a crude ultrasound probe. It worked, so I tried to upgrade it into full-blown ultrasound imaging. The third iteration of that did produce an image, using a piezo buzzer cut in sections, a cheap FPGA, a MCU, custom PCB and mostly 3D printed pieces (acoustic lens, etc.). Aside from the expected low resolution, turned out that it wouldn't image anything beyond about 1 cm.

I did make a fourth iteration of the device, much smaller and theoretically much better. But life happened and I never finished the coding part.

[–] IceWallowCum@hexbear.net 3 points 3 weeks ago (1 children)

A DIY superficial USG could be super useful for emergency lung imaging in low resource centers, if you ever want to keep that project up! Check out BLUE protocol by Lichtenstein et al

[–] pancake@lemmygrad.ml 2 points 3 weeks ago

I fully intend to go on with the project! Right now it's not good enough to be interesting, but the results so far are too promising to not give it a chance.

[–] ganymede@lemmy.ml 3 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

congrats on the excellent project.

how many pieces of the piezo and which frequency of operation did you use?

how did you design/source the acoustic lens design?

seriously well done!!

[–] pancake@lemmygrad.ml 2 points 3 weeks ago

Thank you! :)

I managed to get 4 piezo elements to work, limited by the FPGA. This was actually enough for some reasonable horizontal resolution since I used a phase array configuration, so the downside was the electronics had to generate very precisely timed pulses. The fourth prototype had 10 working elements thanks to replacing the MCU-FPGA duo with just a more powerful FPGA and using conductive glue to more reliably connect the elements themselves.

It was configurable to use any even divisor of 120 MHz, but in practice anything over 1 MHz would not even make it out of the acoustic lens due to the low voltage and low quality impedance matching layer. And much lower frequencies are barely useful anyways, so the true working range was narrow.

For the acoustic lens, I used the parametric design software OpenSCAD, with an equation for aberration-free lenses I had found somewhere and saved long before (will find it if you want) and the speed of sound in the different materials.