Hello,
Recently I visited a small knitting factory with about 20 circular knitting machines. They were pretty rudimentary. I talked to the owner of this factory to understand what they need to improve their manufacturing.
He constantly talked about the needle controller/sensors, how useful it can be if they were to integrate them into each machine in the factory. There are a few companies selling them, but apparently the price is a bit prohibitive. I thought this can be a good opportunity for me because there are many small knitting factories in my city, and I decided to research more about it.
Needle controllers/sensors are basically checks if there are any missing or bent needles in the knitting machine.
I've found a video showing how it works, it's a very short video:How do you think it works? what kind of Lasers they are using to detect broken needles? It seems like they implement kind of a TOF algorithm, but I am not sure and came here to ask for opinions on how these devices work.
The algorithm to detect broken needles must be kind of complicated, as of right now I can't wrap my head around it because knitting machines can rotate at not constant but variable speeds they are not very repeatable in terms of their operation. I just need to brainstorm more I guess.

These are a few devices on the market:
https://www.protechna.de/en/rundstrickmaschinen/needle_sensor_4022https://www.memminger-iro.de/en/ueberwachung/mnc2.php