Chain Buzzer ESPHome Component

Chain Buzzer is a buzzer output node in the M5Stack Chain series. It integrates a built-in buzzer and a programmable RGB LED, making it suitable for sound prompts, status reminders, smart home alarms, and other applications.

Note

To use Chain series nodes, a compatible host is required for UART communication and control, such as the Chain DualKey host, or an Atom series device paired with the Atomic ToChain Base.

1. Component Overview

Item	Information
Expansion module	Chain Buzzer (U224)
Main functions	Turn the buzzer on and off
Communication interface	Chain Bus / UART
ESPHome components	`m5_chain_base`, `m5_chain_buzzer` (external components)
ESPHome version requirement	2026.9.0 or later

2. Component Details

Include External Components

Configuration Example

Configure the host UART pins (using the Chain DualKey as an example)

uart:
  - id: chain_uart_right
    tx_pin: GPIO6
    rx_pin: GPIO5
    baud_rate: 115200

  - id: chain_uart_left
    tx_pin: GPIO47
    rx_pin: GPIO48
    baud_rate: 115200 

Include the external components

external_components:
  - source: github://m5stack/esphome@feat-m5-chain
    components: [m5_chain_base, m5_chain_buzzer]
    refresh: 0s 

Add the Chain Buzzer

m5_chain_buzzer:
  id: chain_buzzer
  uart_id: chain_uart_right
  chain_index: 1 

Set the correct index according to the actual position of the Chain.

Add Chain Buzzer outputs

output:
  - platform: m5_chain_buzzer
    id: chain_buzzer_output
    m5_chain_buzzer_id: chain_buzzer
  - platform: m5_chain_buzzer
    id: chain_buzzer_red
    m5_chain_buzzer_id: chain_buzzer
    channel: rgb_red
  - platform: m5_chain_buzzer
    id: chain_buzzer_green
    m5_chain_buzzer_id: chain_buzzer
    channel: rgb_green
  - platform: m5_chain_buzzer
    id: chain_buzzer_blue
    m5_chain_buzzer_id: chain_buzzer
    channel: rgb_blue 

Add the RTTTL (ringtone text transfer language) component

rtttl:
  output: chain_buzzer_output
  id: chain_buzzer_rtttl 

Add the Chain Buzzer RGB LED

light:
  - platform: rgb
    name: Chain Buzzer RGB
    red: chain_buzzer_red
    green: chain_buzzer_green
    blue: chain_buzzer_blue 

Note that after adding the entities above, Home Assistant cannot control the buzzer directly. You need to add the corresponding preset scripts and template buttons:

script:
  - id: chain_buzzer_beep_twice
    then:
      - m5_chain_buzzer.play:
          id: chain_buzzer
          frequency: 2730
          duty: 50
          time: 100ms
      - delay: 150ms
      - m5_chain_buzzer.play:
          id: chain_buzzer
          frequency: 2730
          duty: 50
          time: 100ms

button:
  # Beep once
  - platform: template
    name: "Buzzer Beep"
    icon: "mdi:bullhorn"
    on_press:
      - m5_chain_buzzer.play:
          id: chain_buzzer
          frequency: 2730
          duty: 50
          time: 120ms
  # Beep twice
  - platform: template
    name: "Buzzer Beep Twice"
    icon: "mdi:bullhorn-outline"
    on_press:
      - script.execute: chain_buzzer_beep_twice
  # Long beep
  - platform: template
    name: "Buzzer Beep Long"
    icon: "mdi:volume-high"
    on_press:
      - m5_chain_buzzer.play:
          id: chain_buzzer
          frequency: 2730
          duty: 50
          time: 1s

  # Silence a running melody or a long auto-play beep.
  - platform: template
    name: "Buzzer Stop"
    icon: "mdi:stop"
    on_press:
      - rtttl.stop:
          id: chain_buzzer_rtttl
      - m5_chain_buzzer.play:
          id: chain_buzzer
          frequency: 1000
          duty: 0
          time: 1ms 

To play content in RTTTL format, use the rtttl.play action, for example:

button:
  - platform: template
    name: "Ring Tone"
    icon: "mdi:cellphone-sound"
    on_press:
      - rtttl.stop:
          id: chain_buzzer_rtttl
      - rtttl.play:
          id: chain_buzzer_rtttl
          rtttl: "RingTone:d=4,o=5,b=225:8e6,8d6,4f#,4g#,8c#6,8b,4d,4e,8b,8a,4c#,4e,2a" 

By creating template buttons and combining them with preset ringtones, you can control the buzzer from the Home Assistant frontend.

3. Reference Example

After the Chain Buzzer expansion module is connected, you can view the corresponding Button and Light entities on the device page:

Dashboard card example

Next Overview

Page Tools

PDF

Home Assistant

HAOS

ESPHome

Controller & Devices

Cameras

Components

Sensors

Lighting

Input Devices

Chain Series

Switches and Relays

Audio Devices

Interfaces and Expansion

Applications

Voice Assistant

Media Playback

Dashboard