My mom gave me her old phone. Now I use it to generate time-lapse videos of my plants.
There are a few problems to solve:
- I have to remove the photos from the phone pretty regularly, or else the phone's storage will fill up.
- When the lights are off, the picture is almost entirely black. I want to detect that and discard those images.
- The intervalometer app on the phone doesn't let me manually set the exposure or focus, so one image can vary from the next. Not much I can do about that.
- The camera sometimes takes the picture upside down. It's not just the EXIF orientation -- the pixels are actually rotated 180 degrees. I want to detect that and rotate those images. This is the tricky part.
I use rsync to move the images from the phone onto my server, imagemagick
(magick) to process the images, and ffmpeg to create the video.
It all happens in ./sync, run as a cron job on the server every hour.
Once in a while I generate the time-lapse and post it to the bottom of https://lookatmyplants.com.