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External Notification Module Configuration

The External Notification Module will allow you to connect a buzzer, speaker, LED, or other device to notify you when a message has been received from the mesh network.

External Notification Module Config Values


Enables the external notification module.

Alert when receiving a bell

Specifies if an alert should be triggered when receiving an incoming bell.

Alert when receiving a message

Specifies if an alert should be triggered when receiving an incoming message.


Specifies whether the external circuit is triggered when the device's GPIO is low or high.

GPIO to monitor

Specifies the GPIO that your external circuit is attached to on the device.

How long monitored GPIO is triggered

Specifies how long in milliseconds you would like your external circuit to be triggered.

Default of 0 is 1000ms

External Notification Module Config Client Availability


All external notification module config options are available on iOS, iPadOS and macOS at Settings > Modules > External Notification.


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.


Alert Types

We support being alerted on two events:

  1. Incoming Text Message

  2. Incoming Text Message that contains the ASCII bell character. At present, only the Python API can send an ASCII bell character, but more support may be added in the future.


The bell character is ASCII 0x07. Include 0x07 anywhere in the text message and with ext_notification.alert_bell enabled, we will issue an external notification.

External Hardware

Be mindful of the max current sink and source of the ESP32 GPIO. The easiest devices to interface with would be either an LED or Active Buzzer.

Ideas for external hardware:

  • LED
  • Active Buzzer
  • Flame thrower
  • Strobe Light
  • Siren

Known Problems

  • This won't directly support a passive (normal) speaker as it does not generate any audio wave forms.
  • This module only monitors text messages. We won't trigger on any other packet types.