meshtastic/docs/software/modules/external-notifications.md

---
id: ext-notif-module
title: External notifications
sidebar_label: External notifications
---
import PluginModule from '@site/docs/_blocks/_plugin_module.mdx';

## About

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.

## Configuration

<PluginModule name="ext_notification_" rename="ext_notification_"/>

These are the settings that can be configured.

    ext_notification_module_enabled
        Is the module enabled?

        0 = Disabled (Default)
        1 = Enabled

    ext_notification_module_active
        Is your external circuit triggered when our GPIO is low or high?

        0 = Active Low (Default)
        1 = Active High

    ext_notification_module_alert_message
        Do you want to be notified on an incoming message?

        0 = Disabled (Default)
        1 = Alert when a text message comes

    ext_notification_module_alert_bell
        Do you want to be notified on an incoming bell?

        0 = Disabled (Default)
        1 = Alert when the bell character is received

    ext_notification_module_output
        What GPIO is your external circuit attached?

        GPIO of the output. (Default = 13)

    ext_notification_module_output_ms
        How long do you want us to trigger your external circuit?

        Amount of time in ms for the alert. Default is 1000.

## Usage Notes

For basic usage, start with:

    ext_notification_module_enabled = 1

    ext_notification_module_alert_message = 1

Depending on how your external circuit is configured, you may need to set the active state to true.

    ext_notification_module_active = 1

:::note
The device must be restarted after the settings have been changed for the module to take effect.
:::

### 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.

#### Bell Character

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

## 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.