Fancy Waybar Configurations

By Speedsquirrel - July 28, 2025

1. Waybar Folder Structure

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waybar
├── brightness
├── config
├── scripts
│   ├── ice_speed.sh
│   └── mqtt_co2.sh
├── style.css
└── update_brightness.sh

To display the brightness of my screen (e.g., on a laptop), I created a small shell script that gets triggered every time I adjust the brightness through my window manager:

Bash

#!/bin/bash
light -G | awk '{printf "☀ %.0f%%\n", $1}' > /home/user/.config/waybar/brightness

The script saves the current brightness level to /home/user/.config/waybar/brightness, which is then read and displayed by my Waybar configuration:

JSON

"custom/brightness": {
  "format": "{}",
  "exec": "cat /home/user/.config/waybar/brightness",
  "interval": 1
},

2. Displaying ICE Train Speed in Waybar

I also created a small script that shows me how fast the train I’m currently on is moving, by using the iceportal API.

If I’m connected to the ICE Wi-Fi (WIFIonICE), the script automatically fetches the current train speed:

Bash

#!/bin/bash

SSID=$(nmcli -t -f active,ssid dev wifi | grep '^yes' | cut -d: -f2)

if [ "$SSID" = "WIFIonICE" ]; then
  SPEED=$(curl -s https://iceportal.de/api1/rs/status | jq -r '.speed')

  if [[ "$SPEED" == "null" || -z "$SPEED" ]]; then
    echo "{\"text\": \"🚅 ???\", \"tooltip\": \"No speed available\"}"
  elif (( $(echo "$SPEED > 200" | bc -l) )); then
    echo "{\"text\": \"🚀 ${SPEED} km/h\", \"tooltip\": \"ICE speed\"}"
  else
    echo "{\"text\": \"🚅 ${SPEED} km/h\", \"tooltip\": \"ICE speed\"}"
  fi
else
  echo "{\"text\": \"\", \"tooltip\": \"\"}"
fi

This script is then integrated into the config.jsonc of Waybar:

JSON

"custom/ice_speed": {
  "exec": "~/.config/waybar/scripts/ice_speed.sh",
  "interval": 5,
  "return-type": "json",
  "format": "{}",
  "tooltip": true
},

3. Integrating CO₂ Traffic Light Data into Waybar (via MQTT)

Step 1: Install MQTT Broker

First, you need to install mosquitto:

Bash

sudo dnf install mosquitto

Make sure Mosquitto listens on all interfaces. Edit the file /etc/mosquitto/mosquitto.conf if necessary:

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listener 1883
allow_anonymous true

If needed, open the port in your firewall:

Bash

sudo firewall-cmd --permanent --add-port=1883/tcp
sudo firewall-cmd --reload

Step 2: Configure the CO₂ Traffic Light

Flash your CO₂ traffic light with custom firmware that supports MQTT. Then configure it to publish to your MQTT broker (use your PC’s IP address as the broker, and leave the username empty if no authentication is required).

The device will send data to a topic like:

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Co2/Ampel_1

Example payload:

JSON

{"co2":"872","temp":"20.31","hum":"42","lux":"318"}

Step 3: Create a Waybar Script

Create a script called mqtt_co2.sh under ~/.config/waybar/scripts/:

Bash

#!/bin/bash

payload=$(mosquitto_sub -h localhost -t "Co2/Ampel_1" -C 1)
co2=$(echo "$payload" | jq -r .co2)

text="CO₂: ${co2} ppm"
class=""

if [[ "$co2" -lt 800 ]]; then
  class="green"
elif [[ "$co2" -lt 1000 ]]; then
  class="yellow"
elif [[ "$co2" -lt 1200 ]]; then
  class="red"
else
  class="blinking"
fi

echo "{\"text\": \"$text\", \"tooltip\": \"CO₂ value from sensor\", \"class\": \"$class\"}"

Step 4: Add the Module to Waybar

In your config.jsonc, add the module:

JSONC

"custom/co2": {
  "exec": "~/.config/waybar/scripts/mqtt_co2.sh",
  "interval": 10,
  "return-type": "json"
}

Also define the required CSS classes in your style.css:

CSS

#custom-co2.green {
  color: #00ff00;
}
#custom-co2.yellow {
  color: #ffff00;
}
#custom-co2.red {
  color: #ff0000;
}
#custom-co2.blinking {
  color: #ff0000;
  animation: blink 1s infinite;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}