[HermannSW]

A group of MIT students did synchronize 16 PIs with 16 cameras just over GPIOs to shoot at exactly the same point in time. And they built in microsecond delay for adjusting on when exactly the bullet has passed through apple and leaves: https://news.ycombinator.com/item?id=20635132

[dekhn]

edgerton would be proud

[HermannSW]

True, and he started with 1/100,000 second exposure time humming-bird images 83 years ago!

The MIT group used a flash with 0.5us exposure time. I asked for details without answer yet, but assume that it is costly (Vela One does cost 940£) and one-shot, no fast repeating flashes (Vela One has only 50Hz maximal continuous strobe frequency).

I used cheap 2$ 5000lm LEDs with 7$ led driver to convert mains to 38V/1.5A DC. I was able to do global external shutter captures with that led with 4us shutter time, did not try below yet. Most interestingly these LEDs allowed for 8.33us flashes at 9KHz frequency and used that to capture 109m/s flying airgun pellet 10 times in a single multiple exposure frame (9000eps, exposures per second). PI pwm should easily allow for 90,000eps frames for capturing 900m/s 0.50bmg bullets multiple times per frame in flight ...

You can do the same with 6$ Raspberry v1 camera clone (not with v2), bill of materials as well as global external shutter setup, software and example captured frames can be found here:

https://github.com/Hermann-SW/Raspberry_v1_camera_global_ext...