Message Bus¶

The VOICEN OS uses MQTT as a message bus. We can control LEDs and AMP via the message bus. We can also subscribe touch key events from the message bus.

Turn On/Off the LEDs¶

mosquitto_pub -t /voicen/leds/value -m 0xf
mosquitto_pub -t /voicen/leds/value -m 0x0

Enable or Disable the AMP¶

mosquitto_pub -t /voicen/amp -m 1
mosquitto_pub -t /voicen/amp -m 0

Detect touch key events¶

mosquitto_sub -t /voicen/touch

How it works¶

mosquitto is used as the MQTT broker. A IO service is running at background to receive IO control messages and send touch key event.

You can enable, disable, start, stop or restart the IO service with systemctl:

sudo systemctl stop io
sudo systemctl start io
sudo systemctl restart io
sudo systemctl status io
sudo systemctl disable io
sudo systemctl enable io

• the IO program is a python script at /usr/local/bin/io_service.py
• the IO systemd service is at /etc/systemd/system/io.service