otone

otone is a small OpenWrt/Linux command line tool for playing beeps, alerts, chirps, and simple melodies through a router buzzer connected to GPIO sysfs.

It is useful for OpenWrt router diagnostics, audible boot/status alerts, GPIO buzzer testing, embedded Linux experiments, and tiny shell-script notifications.

Features

• Written in C with minimal dependencies
• Works through /sys/class/gpio/.../value
• Auto-detects common buzzer GPIO paths
• Saves the detected buzzer path to /etc/otone.conf
• Supports fixed frequency beeps, silence, PWM volume, and chirp frequency sweeps
• Optional verbose diagnostics and simple timing statistics
• Includes a Mario melody script example in sounds/mario.sh

Install on OpenWrt

SSH into the router and run:

opkg update
opkg install git git-http gcc make libc-dev
cd /tmp
git clone https://github.com/BlackF1re/otone.git
cd otone
make
install -D -m 0755 ./otone /usr/bin/otone
otone 2000 300

If the repository is still available through the old GitHub redirect, this also works:

opkg update
opkg install git git-http gcc make libc-dev
cd /tmp
git clone https://github.com/BlackF1re/tone.git otone
cd otone
make
install -D -m 0755 ./otone /usr/bin/otone
otone 2000 300

Install from a local Linux PC

git clone https://github.com/BlackF1re/otone.git
cd otone
make
scp ./otone root@192.168.1.1:/usr/bin/otone
ssh root@192.168.1.1 'chmod +x /usr/bin/otone && otone 2000 300'

Manual build

gcc -O2 -Wall -Wextra -std=c99 -o otone otone.c -lm

Build with a fixed GPIO path to skip detection:

gcc -O2 -Wall -Wextra -std=c99 -DBUZZER_GPIO_PATH='"/sys/class/gpio/gpio10/value"' -o otone otone.c -lm

Usage

otone <frequency_hz> <duration_ms> [options]

Examples:

otone 2000 300
otone 0 1000
otone 2500 300 -p 50
otone 1000 800 -c 4000
otone 2000 300 -d /sys/class/gpio/gpio10/value
otone 2000 300 -vv

Options:

-d, --device PATH   GPIO value file for the buzzer
-p, --pwm VALUE     PWM volume from 0 to 100
-c, --chirp HZ      Sweep from the start frequency to HZ
-v, --verbose       Verbose output
-vv                 Verbose output with statistics
-h, --help          Show help

Configuration

The detected path is saved to:

/etc/otone.conf

Example config:

buzzer_path=/sys/class/gpio/gpio10/value
spin_threshold_us=100
default_volume=100
enabled=1

Melody example

chmod +x sounds/mario.sh
sounds/mario.sh mario
sounds/mario.sh underworld
sounds/mario.sh both

Troubleshooting

No sound:

ls -la /sys/class/gpio
cat /etc/otone.conf 2>/dev/null || true
otone 2000 300 -v
otone 2000 300 -d /sys/class/gpio/gpio10/value

Permission error:

ssh root@192.168.1.1
otone 2000 300

Compiler missing:

opkg update
opkg install gcc make libc-dev

License

BSD 3-Clause. See LICENSE.