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sync external flash (light)

Posted: Thu Jul 25, 2019 9:29 pm
by henrique_mg
I would like to enable and sync external flash (light) to make the photo. How can I do this?

Re: sync external flash (light)

Posted: Fri Jul 26, 2019 8:46 am
by stereomaton
I think triggering a commercial flash is done by shorting two pins of its connector (keyword: hotshoe).
However, because it is high voltage (compared to stereopi) you will need to add some electronics between the stereopi and the flash, probably only an optocoupler and resistors. I let you make your search, there are probably some montages for Arduino that would work straight forward with stereopi.
Of course, you will have to add a gpio change in the script that launches the photo capture with an appropriate delay that can be tricky to tune; and I think there is a flag in raspistill to expose for flash light that might be good to add too.
Have fun, and keep us informed of your progress.

Re: sync external flash (light)

Posted: Fri Jul 26, 2019 9:03 am
by Realizator
Hi all!
Sorry for silence - I was forced to be offline for a several days.

You can try to use external flash the same way as with the classic Raspberry Pi.
Here is a guide: https://picamera.readthedocs.io/en/rele ... the-camera
Please also read this comment from 6by9: https://www.raspberrypi.org/forums/view ... 52#p958970

Also, you need to use StereoPis DTS files, but not stock DTS. You can find our DTS here in our Wiki.