Using a Raspberry Pi and Camera module to retroactively record footage?

Question

Hi all,

I have recently bought a Pi3 and camera module.

I'm not sure if what i'm looking to do is possible. Basically i'd like to have the camera running and constantly recording, then when an action is executed (button press mouse click, touch on tablet) saving the previous X amount of seconds of video and storing it.

For example I set the camera to run and record a road near me. When I see an interesting car drive by, I press the button and it saves the last 10 seconds so I can see the make of the car.

Is something like this possible?

Thanks for any help.

beacon_dave · Answer

Raspivid may be of interest as it appears to now incorporate a circular recording buffer: https://www.raspberrypi.org/forums/viewtopic.php?t=65450&p=484954

rew · Answer

In theory this is possible. A program called "motion" does something like this. It uses moving things in the video data to determine when to output a video of the "incident". I am not sure if it supports other "inputs" that trigger a recording. If it doesn't it shouldn't be too hard to modify it it add that feature....