Wednesday, the Gumstix Overo Fire-based video recorder was finally assembled and wired as it would go on the rocket.
This was also the first time I had the opportunity to run some long duration tests. To avoid having a static image, I mounted the camera on a fan with panning functionality. On the picture below you can see how the camera is connected directly to the USB OTG port on the Tobi expansion board with the power fed directly from the regulator.
Watch video on YouTube.
Unfortunately, these tests revealed that the setup stops working after a while due to a device I/O error from the camera. The time when the errors occurs is random. Initially I suspected that it might be due to ripple in the supply voltage (the spec for the switching regulator state max 2%), but later tests using external power supply dismissed this possibility. Thus the problem is with the USB data connection. I don’t know much about USB, I guess one can not just bypass a USB hub?
Anyway, the quick-fix solution was to let the capture script run in a loop. so even it the Gstreamer pipeline breaks due to the error, it will simply be restarted. This solution seems to work well and produces playable videos.
Finally, here is a close-up of how I managed to tighten the Gumstix Overo Fire computer module onto the Tobi expansion board. The holes are 1.6 mm I think and I didn’t find any place nearby that had such small screws. So I just tightened the board using some stiff wire.