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External notifications


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

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_module_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


Configuration details are available on the Device Settings pages. Configuring the External Notification Module requires configuring the following modules:

Known Problems

  • This won't directly support a passive (normal) speaker as it does not generate any audio wave forms.
  • This currently only supports the ESP32. Other targets may be possible, I just don't have to test with.
  • This module only monitors text messages. We won't trigger on any other packet types.