Add automatic brightness dimming on low battery for laptops

[martin-joshy]

I think this is a better way to remind yourself to plug in your laptop. Currently in Omarchy, when the battery reaches the threshold, only a notification is sent and I tend to miss out on this notification if I am not at my desk or maybe for some other reason.

But dimming the brightness gives me better feedback, or maybe it is just an old habit from my Windows days. 🥲

Hope this simple solution/idea helps someone.

Steps

1. Copy and Modify the Battery Monitor Script

Copy the original battery monitor script:

cp ~/.local/share/omarchy/bin/omarchy-battery-monitor ~/.local/bin/my-battery-monitor

Modify by adding the reduce_brightness function:

#!/bin/bash
# Designed to be run by systemd timer every 30 seconds and alerts if battery is low

BATTERY_THRESHOLD=25
NOTIFICATION_FLAG="/run/user/$UID/omarchy_battery_notified"
BATTERY_LEVEL=$(omarchy-battery-remaining)
BATTERY_STATE=$(upower -i $(upower -e | grep 'BAT') | grep -E "state" | awk '{print $2}')

send_notification() {
  notify-send -u critical "󱐋 Time to recharge!" "Battery is down to ${1}%" -i battery-caution -t 30000
}

reduce_brightness() {
  brightnessctl set 10%
}

if [[ -n "$BATTERY_LEVEL" && "$BATTERY_LEVEL" =~ ^[0-9]+$ ]]; then
  if [[ $BATTERY_STATE == "discharging" && $BATTERY_LEVEL -le $BATTERY_THRESHOLD ]]; then
    if [[ ! -f $NOTIFICATION_FLAG ]]; then
      send_notification $BATTERY_LEVEL
      touch $NOTIFICATION_FLAG
      reduce_brightness
    fi
  else
    rm -f $NOTIFICATION_FLAG
  fi
fi

2. Mask the Original Omarchy Battery Monitor

To avoid using the omarchy-battery-monitor after updates, mask it:

systemctl --user mask omarchy-battery-monitor.timer
systemctl --user mask omarchy-battery-monitor.service

3. Create the Service File

nvim ~/.config/systemd/user/my-battery-monitor.service

Add the following content:

[Unit]
Description=Modified battery monitor off omarchy-battery-monitor

[Service]
Type=oneshot
ExecStart=/home/yourusername/.local/bin/my-battery-monitor

Note: Replace yourusername with your actual username.

4. Create the Timer File

nvim ~/.config/systemd/user/my-battery-monitor.timer

Add the following content:

[Unit]
Description=Modified battery monitor off omarchy-battery-monitor
Requires=my-battery-monitor.service

[Timer]
OnBootSec=10sec
OnUnitActiveSec=30sec
Persistent=true

[Install]
WantedBy=timers.target

5. Enable and Start Your New Timer

systemctl --user daemon-reload
systemctl --user enable --now my-battery-monitor.timer

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That's it! Your battery monitor will now dim the brightness to 10% along with sending a notification when your battery drops to the threshold.