Time lapse

February 4, 2021

Super brief post about one of the more fun projects I setup recently: a lil’ time lapse script

#!/bin/bash
CAM=$(v4l2-ctl --list-devices | grep C920 -A 1 | grep /dev | awk '{$1=$1};1')
#Uncomment the next line to verify it's using the correct device
#echo $CAM
ffmpeg -f video4linux2 -s 1920x1080 -i $CAM -ss 0:0:2 -frames 1 "/mnt/data/lapse/tl$(date +"%Y-%m-%d_%H-%M-%S").jpg"

I have multiple cameras on my system, but only wanted output from the better one, the C920. That’s what line 2 is doing, finding the /dev/videoX device, where X is the correct number for the webcam

Line 5 takes the picture and saves it with the current date and time in the /mnt/data/lapse folder

Then, to trigger the script I have a systemd timer and service setup.

I have the timer and service files named fifteen.timer and fifteen.service respectively, and the script above is named fifteen.sh and is stored in ~/.config/fifteen.sh This is so that I can add extra things do on fifteen minute intervals if needed super easily. I also have an hourly.sh with a similar setup.

fifteen.service

[Unit]
Description=run ~/.config/fifteen.sh

[Service]
Type=simple
ExecStart=/bin/bash /home/vega/.config/fifteen.sh

fifteen.timer

[Unit]
Description=Take Hourly Webcam Picture

[Timer]
OnCalendar=*:0/15
Unit=fifteen.service

[Install]
WantedBy=timers.target

So with all of that setup, I can finally get poorly timed, slightly blurry pictures of myself drinking directly from a 2L bottle of Mello Yello automatically.

Note, this picture has been resized by 50% for web, actual quality is a better