Is it possible to trigger two Cameras connected by USB to a single RPi at the same time with 1 ms latency?
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It is certainly possible to send two USB messages within one ms of each other. It's used for 100 Mbps Ethernet which is considerably faster. It depends on how the cameras are triggered.– joanCommented Mar 1, 2016 at 4:54
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2 Answers
If you have the right Canon cameras you can use the Canon Hack Development Kit CHDK. I use that and StereoData Maker to trigger two cameras. You turn the 5v USB pin on to trigger the camera so you need to convert the 3v gpio to 5v.
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I have used the CHDK with a pair of Canon cameras and an external trigger. The application of 5v (4.5v in my case, 3x AA batteries) causes my cameras to focus, while the release of the 5v triggers the shutter. Something to consider for the OP's application of low latency. Commented Jul 23, 2016 at 11:51
Try something like;
streamer -c /dev/video0 -b 16 -o a.jpg & streamer -c /dev/video1 -b 16 -o b.jpg &
The & makes the second command run without waiting for the first one to finish.
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Not sure about the answer of @user1133275 because the each camera may have latency during the shooting so the command may run serially.– Ali FCommented Mar 24, 2016 at 20:24