[Unit]
Description="Turn keyboard backlight on/off bases on light sensor"

[Service]
Type=oneshot
RemainAfterExit=yes
Environment="SENSOR=/sys/bus/iio/devices/iio::device2/in_illuminance_raw"
WorkingDirectory=/sys/class/leds/dell::kbd_backlight/
ExecStart=bash -c "[[ $(cat ${SENSOR}) < 1500  ]] && echo 1 > brightness || echo 0 > brightness"

[Install]
WantedBy=multi-user.target