Audio Module Configuration

The audio module config options are: Codec2 Enabled, PTT GPIO, Audio Bitrate/Codec Mode, I2S Word Select, I2S Data IN, I2S Data OUT and I2S Clock. Audio Module config uses an admin message sending a ConfigModule.Audio protobuf.

With this experimental module, you can add a digital I2S microphone and speaker to any ESP32 device that has a SX128x radio and operates on the 2.4 GHz ISM Band. The Sub-1GHz bands are not wide enough to support continuous audio packets on the mesh, even in the Short and Fast modes. Right now, the only devices supported are the LilyGo TLora 2.1-1.8 and TLora T3S3 boards. The module has been designed for channels with 2kbit / sec of bandwidth or greater.

Required additional hardware:

• Max98357 - I2S 3W Class D Amplifier
• MSM261S4030H0 - I2S MEMS Low Noise Single Microphone

Audio Module Config Values

Codec2 Enabled

Enables the audio module.

PTT GPIO

The GPIO to use for the Push-To-Talk button. The default is GPIO 39 on the ESP32.

Audio Bitrate/Codec Mode

The bitrate to use for audio. The default is CODEC2_700B. The available options are:

• CODEC2_DEFAULT
• CODEC2_3200
• CODEC2_2400
• CODEC2_1600
• CODEC2_1400
• CODEC2_1300
• CODEC2_1200
• CODEC2_700B
• CODEC2_700

I2S Word Select

The GPIO to use for the WS signal in the I2S interface.

I2S Data IN

The GPIO to use for the SD signal in the I2S interface.

I2S Data OUT

The GPIO to use for the DIN signal in the I2S interface.

I2S Clock

The GPIO to use for the SCK signal in the I2S interface.

What is this?

These Pins comprise an I2S digital audio interface. Meshtastic uses it in monoaural mode. The software will use the logical 'LEFT' Stereo channel for the microphone and the logical 'RIGHT' Stereo channel for the speaker, so configure your breakouts accordingly. Audio is Half-Duplex, so we can re-use part of the pins for a bi-directional configuration. There's no default pin assignment, setting these is mandatory.

Audio Module Config Client Availability

Android

Android

info

Audio Config options are available for Android.

1. Open the Meshtastic App
2. Navigate to: Vertical Ellipsis (3 dots top right) > Radio Configuration > Audio

Apple

Apple

info

Audio module config is not available on iOS, iPadOS and macOS.

CLI

CLI

info

All audio module config options are available in the python CLI. Example commands are below:

Setting	Acceptable Values	Default
audio.codec2_enabled	true, false	false
audio.ptt_pin	GPIO Pin Number 1-39	Default of 39 is Unset
audio.bitrate	CODEC2_DEFAULT CODEC2_3200 CODEC2_2400 CODEC2_1600 CODEC2_1400 CODEC2_1300 CODEC2_1200 CODEC2_700B CODEC2_700	CODEC2_DEFAULT
audio.i2s_ws	GPIO Pin Number 1-34	no Default
audio.i2s_sd	GPIO Pin Number 1-39	no Default
audio.i2s_din	GPIO Pin Number 1-34	no Default
audio.i2s_sck	GPIO Pin Number 1-34	no Default

tip

Because the device will reboot after each command is sent via CLI, it is recommended when setting multiple values in a config section that commands be chained together as one.

Example:

meshtastic --set audio.codec2_enabled true --set audio.bitrate CODEC2_1400

Enable / Disable Module

meshtastic --set audio.codec2_enabled true
meshtastic --set audio.codec2_enabled false

Set WS to GPIO pin number 7

meshtastic --set audio.i2s_ws 7

Set DIN to GPIO pin number 28

meshtastic --set audio.i2s_din 28

Set PTT to GPIO pin number 37

meshtastic --set audio.ptt_pin 37

Set Codec Bitrate

meshtastic --set audio.bitrate CODEC2_DEFAULT
meshtastic --set audio.bitrate CODEC2_1400

Web

Web

info

All audio module config options are available in the Web UI.

warning

GPIO access is fundamentally dangerous because invalid options can physically damage or destroy your hardware. Ensure that you fully understand the schematic for your particular device before trying this as we do not offer a warranty. Use at your own risk.

This module requires attaching a peripheral accessory to your device. It will not work without one.