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Synchronization of light and exposure

Pixy Hardware
#1

Hi all,

For a project we are working on, we would like to turn on few LED’s when the pixy is actually taking images, so that the LED is synchronized with the exposure time of the camera.
Usually cameras do have a line output following the exposure time, and that can be used to trigger external lighting. The idea is that the light only turns on when the camera is integrating, and the rest of the time is off. This might lead to substantial improvement in light on the image and power savings (just turn on the light when there is something to look at) with respect to asynchronous acquisition.

I would like to know if anybody actually tried this with the pixy or if this is even possible.

Thanks

#2

Hi Carlos,

your question is a little bit confusing, since Pixy is a video device, and not a still camera. It sounds like the method you are referring to is for long exposure times on traditional SLR and DSLR cameras. Pixy is continuously processing frames as long as power is applied, so any sort of power cycling of LED lights would happen at 50 frames per second, and may not afford much power savings.

You might be able to set up something like this though with a motion detector circuit - Google “diy wildlife camera flash” for examples of this type of thing.

Let me know if that helps!

Cheers,
Jesse

#3

Hi Jesse,
Thank you for your reply. The feature I am mentioning is not uncommon in camera chipsets. Indeed toggling 30 times per second might be worth it. If the camera exposes for 1/3 of the vsynch time you can save up to 66% of lighting power!!! When things are battery operated this matters.
Check for instance the OV9655 strobe mode Led lighting.

I expected maybe a pin in the pix with that feature. Anyone??

Carlos

#4

I see, now I understand a bit more about what you’re trying to do. Pixy captures frames at 50fps, so the LED array would be power cycling every 20 milliseconds. Unfortunately the sensor chip doesn’t support the same strobe mode as the OV9655 - we’re actually using the OV9715 on Pixy.

What application are you using Pixy for?

Thanks,
Jesse