Automatically Start/Stop Motion Activated Camera When Cellphone Not On Local Network

Note: This Systemd service will detect if your mobile phone is on the local network using ping, therefore, it should have a static IP address when it connects to your Wi-Fi network.

1. ~/.config/systemd/user/surveillance-system.service

    [Unit]
    Description=Automatically Start/Stop Surveillance System if phone not on local network
    Wants=surveillance-system.timer
   
    [Service]
    Type=simple
    ExecStart=/home/USERNAME/.config/systemd/user/start-motion-detection.sh
   
    [Install]
    WantedBy=multi-user.target
   

2. ~/.config/systemd/user/surveillance-system.timer (check for mobile phone presence every minute)

    [Unit]
    Description=Automatically Start/Stop Surveillance System if phone not on local network
   
    [Timer]
    OnCalendar=*:0/1
   
    [Install]
    WantedBy=timers.target
   

3. ~/.config/systemd/user/start-motion-detection.sh

    #!/bin/bash
    XDG_RUNTIME_DIR=/run/user/$(id -u)
    DBUS_SESSION_BUS_ADDRESS=unix:path=${XDG_RUNTIME_DIR}/bus
    export DBUS_SESSION_BUS_ADDRESS XDG_RUNTIME_DIR
   
    ping -W 1 -c 1 192.168.0.20 > /dev/null
    if [ $? -ne 0 ]; then # Host is down, start motion
      echo "Host is down..."
        if pgrep -x "motion" >/dev/null
        then
          echo "Motion already running..."
        else
          echo "Motion is not running, sarting it..."
          motion
        fi
   
    else # Host is up, stop processes
      echo "Host is up..."
      if pgrep -x "motion" >/dev/null
      then
        echo "Stopping Motion..."
        killall motion
      else
        echo "Motion is not running."
      fi
    fi
   

4. Commands to start the service and check its status:

    systemctl --user enable surveillance-system.timer --now
    systemctl --user start surveillance-system.timer --now
    systemctl --user list-timers
    systemctl --user status surveillance-system
   

5. I hade issues where the phone would not connect to Wi-Fi fast enought when I was in range of the router, and it helped when I did this:

   In LineageOS 18.1 > Network & internet > Wi-Fi > Wi-Fi preferences > toggle On: Turn on Wi-Fi automatically: “Wi-Fi will turn back on near high-quality saved networks, like your home network”. (unfortunately, this requires location to be turned ON, also)