ASUS ExpertBook B9450 LED Bar Control (expertbook-led)

A lightweight, native C++ utility to control the proprietary front panel LED strip (historically known as the Alexa Light Bar) on the ASUS ExpertBook B9450 laptop running Linux.

This project interacts directly with the embedded ITE IT8232FN micro-controller using the native HID-over-I2C kernel subsystem (/dev/hidraw), providing a fast, zero-dependency solution without bloated background daemons.

Features

• Trigger 20 built-in hardware animation presets.
• Control global maximum brightness via a 32-step hardware PWM scale.
• Directly control the five RGB zones with custom colors.
• Query the controller LED-zone count or turn the Light Bar off.
• Adjust animation loop counts or unlock endless loops.
• Ability to acts as VU meter (fancy led bar with peaks indicator).
• Integrated udev setup allowing secure execution from standard non-root user space.

Prerequisites

Ensure you have a modern Linux kernel and the hidapi compilation libraries.

On Debian/Ubuntu based systems:

sudo apt install libhidapi-dev g++ make

Installation

1. Build the binary from source:

   make

2. System-wide installation (installs the binary to /usr/local/bin and automatically configures safe udev hardware permissions):

   sudo make install

Usage Examples

Once installed, the utility can be seamlessly integrated into user shell environments, event hooks, or cron timers:

• Play a specific built-in hardware animation (e.g., effect #5):

  expertbook-led --effect 5

• Dim the bar's maximum intensity down to night-friendly level (values 1 to 32):

  expertbook-led --brightness 8

• Set animations to loop exactly 3 times globally, then play effect #12:

  expertbook-led --repeat 3
  expertbook-led --effect 12

• Allow hardware effects to run endlessly:

  expertbook-led --infinite

Direct RGB Control

The ALED0217 controller also supports direct five-zone RGB control on confirmed hardware.

Set all five zones to one color:

expertbook-led --rgb 255 0 0

Set the five zones independently:

expertbook-led --rgb-zones \
  255 0 0 \
  0 255 0 \
  0 0 255 \
  255 255 255 \
  0 128 255

Query the controller LED-zone count:

expertbook-led --led-count

On the tested ASUS ExpertBook B9400CBA/B9450CBA the controller reports 5 zones.

Turn the Light Bar off:

expertbook-led --off

The direct RGB path performs the confirmed LED-count handshake before sending RGB data.

Acts as VU meter

On modern linux distributions with the pipewire audio subsystem, please try to run the following command:

pw-record -P '{ stream.capture.sink=true }' --channels=1 --format=s16 --rate=44100 - 2>/dev/null | ./expertbook-led --audio

It will pipe the captured audio data from pw-record to the expertbook-led in audio mode and will display a fancy VU-meter until you stop it by Ctrl+C. Enjoy! :)

Desktop Notifications Integration (D-Bus Bridge)

You can turn the Alexa Light Bar into a physical notification center for your Linux desktop environment (GNOME, KDE, XFCE, etc.). By intercepting the org.freedesktop.Notifications interface via D-Bus, the LED bar can flash whenever a system app, messenger (Telegram, Slack), or browser triggers a popup notification.

1. Notification Listener Script

Create a script named expertbook-notifier.sh:

#!/bin/bash
LED_UTIL="/usr/local/bin/expertbook-led"

stdbuf -oL dbus-monitor "interface='org.freedesktop.Notifications',member='Notify'" | while read -r line; do
    if echo "\$line" | grep -q "member=Notify"; then
        URGENCY=1
        PARAM_BLOCK=\$(timeout 0.05 cat)
        
        if echo "\$PARAM_BLOCK" | grep -A1 '"urgency"' | grep -q "byte 2"; then
            URGENCY=2 # Critical
        elif echo "\$PARAM_BLOCK" | grep -A1 '"urgency"' | grep -q "byte 0"; then
            URGENCY=0 # Low
        fi

        case "\$URGENCY" in
            2) \$LED_UTIL --effect 8 ;; # Critical
            0) \$LED_UTIL --effect 1  ;; # Low
            *) \$LED_UTIL --effect 5  ;; # Normal
        esac
    fi
done

Make it executable: chmod +x expertbook-notifier.sh

2. Auto-start on Login (Systemd User Service)

To run this listener automatically in the background when your graphical desktop session loads, configure it as a systemd user service.

Create the service file inside your user directory at ~/.config/systemd/user/expertbook-notifier.service:

[Unit]
Description=ASUS ExpertBook LED Notification Bridge
After=graphical-session.target

[Service]
Type=simple
ExecStart=/home/YOUR_USERNAME/.local/bin/expertbook-notifier.sh
Restart=always
RestartSec=3

[Install]
WantedBy=default.target

(Make sure to change YOUR_USERNAME and the file path to point to your exact script location).

Enable and start the service (no root/sudo privileges required):

systemctl --user enable --now expertbook-notifier.service

Now, your front panel hardware LED bar will subtly pulse whenever your system delivers any desktop event!

---

Technical Protocol Mapping

All operations construct targeted 33-byte HID Feature Reports aiming at VID: 0x0B05 / PID: 0x0124 using Report ID 32 (0x20).

Byte 0 (Report ID)	Byte 1 (Sub-Command)	Byte 2 (Parameter)	Remaining Bytes (3-32)	Functional Description
32	1	1-20	0...	Fires an internal hardware animation routine.
32	2	2	0...	Modifies playback cycle loop state to infinity.
32	3	1-255	0...	Saves discrete animation loop counts to controller registers.
32	4	1-32	0...	Compresses hardware LED brightness matrix (5-bit PWM).

Additional confirmed ALED0217 reports

The following Feature Reports were validated on physical ASUS ExpertBook B9400CBA/B9450CBA hardware using the same 0B05:0124 controller.

LED-count query:

20 C1 02

A subsequent Feature Report read for Report ID 0x20 returned:

20 C1 02 05

The returned 0x05 identifies the five-zone path on the tested hardware.

Direct five-zone RGB:

20 80 00 20
R1 G1 B1
R2 G2 B2
R3 G3 B3
R4 G4 B4
R5 G5 B5

The report is zero-padded to 33 bytes.

Off command:

20 07

also zero-padded to 33 bytes.

The protocol was validated through Linux HID Feature Reports on a physical ASUS ExpertBook B9400CBA/B9450CBA.

License

MIT License. Feel free to copy, modify, and integrate.