A few years ago, I saw a post by a fellow Youtuber https://www.youtube.com/watch?v=MUdro-6u2Zg talking about Laser-Diode Self-Mixing Interferometry and desperately wanted to experiment with the concept.
I work at a university and besides the idea being ridiculously geeky cool all by itself, I know of a few students that wanted to do vibration measurements, and one student that was doing vibration measurements with extremely expensive laser based equipment that maybe…just maybe…I could replace / supplement with something very inexpensive and therefore accessible to anyone that needed it.
Wouldn’t it be great to have every desk in my lab include a device that could do sub-micron velocity measurements for less than $100 per unit? Hell yeah!
As usual, actually digging in to the project took many months, but I finally threw everything else to the side when I took a Christmas 2023 staycation and mostly ignored the world for a couple of weeks. I now have about 6 or 7 different iterations of this quest, including one that is just 7 inches long and 1.25 inches in diameter, powered by a 9V battery.
It’s not too different from this version except for being very portable:
https://www.youtube.com/watch?v=zw6BBU7A6oo&t=1056s
MECHATRONICS dOt LIFE 