Waveshare ESP32-S3-RLCD-4.2

Product Description

ESP32-S3 development board with a 4.2-inch reflective LCD (ST7305, 400x300 monochrome), dual microphone array (ES7210 ADC), speaker output (ES8311 DAC), SHTC3 temperature/humidity sensor, 18650 battery holder with ADC monitoring, and two user buttons The reflective LCD has no backlight and reads like e-paper in sunlight.

Product Images

GPIO Pinout

GPIO	Function
GPIO0	BOOT button (active low)
GPIO4	Battery ADC
GPIO5	Display DC
GPIO8	I2S DOUT (speaker)
GPIO9	I2S BCLK
GPIO10	I2S DIN (microphone)
GPIO11	SPI CLK (display)
GPIO12	SPI MOSI (display)
GPIO13	I2C SDA
GPIO14	I2C SCL
GPIO16	I2S MCLK
GPIO18	KEY button (active low)
GPIO40	Display CS
GPIO41	Display RESET
GPIO45	I2S LRCLK
GPIO46	Speaker amplifier enable

Basic Configuration

substitutions:
  name: "waveshare-esp32-s3-rlcd-42"
  friendly_name: "Waveshare ESP32-S3-RLCD-4.2"

esphome:
  name: "${name}"
  friendly_name: "${friendly_name}"

esp32:
  board: esp32-s3-devkitc-1
  framework:
    type: esp-idf

psram:
  mode: octal
  speed: 80MHz

logger:

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

external_components:
  - source: github://kylehase/ESPHome-ST7305-RLCD
    components: [st7305_rlcd]

I2C Bus

Shared by SHTC3 sensor, ES8311 DAC, and ES7210 ADC.

i2c:
  sda: GPIO13
  scl: GPIO14
  scan: true
  id: bus_a

Display — ST7305 RLCD

Reflective LCD, 400x300 monochrome. Uses SPI.

spi:
  clk_pin: GPIO11
  mosi_pin: GPIO12

display:
  - platform: st7305_rlcd
    model: WAVESHARE_400X300
    id: my_display
    width: 400
    height: 300
    cs_pin: GPIO40
    dc_pin: GPIO5
    reset_pin: GPIO41
    data_rate: 1MHz
    update_interval: 1min
    show_test_card: true

Audio — I2S, ES8311 DAC, ES7210 ADC

Single shared I2S bus for speaker output and dual microphone input.

i2s_audio:
  - id: i2s_shared
    i2s_lrclk_pin: GPIO45
    i2s_bclk_pin: GPIO9
    i2s_mclk_pin: GPIO16

audio_dac:
  - platform: es8311
    id: es8311_dac
    bits_per_sample: 16bit
    sample_rate: 16000

audio_adc:
  - platform: es7210
    id: es7210_adc
    bits_per_sample: 16bit
    sample_rate: 16000
    mic_gain: 24dB

speaker:
  - platform: i2s_audio
    id: i2s_audio_speaker
    i2s_audio_id: i2s_shared
    i2s_dout_pin: GPIO8
    dac_type: external
    audio_dac: es8311_dac
    channel: left
    sample_rate: 16000
    bits_per_sample: 16bit
    buffer_duration: 100ms
    timeout: never

microphone:
  - platform: i2s_audio
    id: va_mic
    i2s_audio_id: i2s_shared
    i2s_din_pin: GPIO10
    adc_type: external
    sample_rate: 16000
    bits_per_sample: 16bit
    pdm: false

switch:
  - platform: gpio
    name: "Speaker Enable"
    pin: GPIO46
    restore_mode: RESTORE_DEFAULT_ON

Sensors

Battery Monitoring

Battery voltage is read via ADC on GPIO4 with a 3x voltage divider. The 18650 cell ranges from 2.5V (empty) to 4.2V (full).

sensor:
  - platform: adc
    id: bat_voltage
    name: "Battery Voltage"
    pin: GPIO4
    attenuation: 12db
    update_interval: 60s
    filters:
      - multiply: 3.0

  - platform: copy
    source_id: bat_voltage
    id: bat_level
    name: "Battery Level"
    unit_of_measurement: "%"
    filters:
      - calibrate_linear:
          - 2.5 -> 0.0
          - 4.2 -> 100.0
      - clamp:
          min_value: 0
          max_value: 100

SHTC3 Temperature and Humidity

  - platform: shtcx
    temperature:
      name: "Temperature"
    humidity:
      name: "Humidity"
    address: 0x70
    update_interval: 60s
    i2c_id: bus_a

Buttons

Two user-accessible buttons, active low.

binary_sensor:
  - platform: gpio
    name: "Boot Button"
    pin:
      number: GPIO0
      inverted: true
      mode: INPUT

  - platform: gpio
    name: "Key Button"
    pin:
      number: GPIO18
      inverted: true
      mode: INPUT

Voice Assistant Configuration

This extends the basic configuration above to add a full voice assistant pipeline with on-device wake word detection, push-to-talk, mute toggle, and media playback. Requires a Home Assistant instance with a Voice Assistant pipeline configured.

api:

ota:
  - platform: esphome

esp32:
  board: esp32-s3-devkitc-1
  framework:
    type: esp-idf
    components:
      - espressif/esp-nn==1.1.2

speaker:
  - platform: i2s_audio
    id: i2s_audio_speaker
    i2s_audio_id: i2s_shared
    i2s_dout_pin: GPIO8
    dac_type: external
    audio_dac: es8311_dac
    channel: left
    sample_rate: 16000
    bits_per_sample: 16bit
    buffer_duration: 100ms
    timeout: never

  - platform: resampler
    id: announcement_speaker
    output_speaker: i2s_audio_speaker

media_player:
  - platform: speaker
    id: speaker_media_player
    name: None
    announcement_pipeline:
      speaker: announcement_speaker
      format: FLAC
      sample_rate: 16000
      num_channels: 1
    files:
      - id: wake_word_triggered_sound
        file: https://github.com/esphome/home-assistant-voice-pe/raw/dev/sounds/wake_word_triggered.flac

micro_wake_word:
  id: mww
  microphone:
    microphone: va_mic
    channels: 0
    gain_factor: 4
  vad:
  models:
    - model: hey_jarvis
  on_wake_word_detected:
    - media_player.speaker.play_on_device_media_file:
        media_file: wake_word_triggered_sound
        announcement: true
    - delay: 300ms
    - voice_assistant.start:
        wake_word: !lambda return wake_word;

voice_assistant:
  id: va
  microphone:
    microphone: va_mic
    channels: 0
    gain_factor: 4
  media_player: speaker_media_player
  micro_wake_word: mww
  use_wake_word: false
  noise_suppression_level: 2
  auto_gain: 31dBFS
  on_error:
    - script.execute: restart_mww
  on_end:
    - script.execute: restart_mww
  on_client_connected:
    - micro_wake_word.start:
  on_client_disconnected:
    - micro_wake_word.stop:

script:
  - id: restart_mww
    then:
      - delay: 500ms
      - wait_until:
          not:
            media_player.is_announcing:
      - wait_until:
          not:
            speaker.is_playing:
              id: i2s_audio_speaker
      - delay: 200ms
      - micro_wake_word.start:

switch:
  - platform: gpio
    name: "Speaker Enable"
    pin: GPIO46
    restore_mode: RESTORE_DEFAULT_ON

  - platform: template
    name: "Mute"
    id: mute_switch
    icon: mdi:microphone-off
    optimistic: true
    restore_mode: RESTORE_DEFAULT_OFF
    on_turn_on:
      - micro_wake_word.stop:
      - voice_assistant.stop:
    on_turn_off:
      - if:
          condition:
            switch.is_on: use_wake_word_switch
          then:
            - micro_wake_word.start:

  - platform: template
    name: "Use Wake Word"
    id: use_wake_word_switch
    icon: mdi:chat-processing
    optimistic: true
    restore_mode: RESTORE_DEFAULT_ON
    on_turn_on:
      - if:
          condition:
            not:
              switch.is_on: mute_switch
          then:
            - micro_wake_word.start:
    on_turn_off:
      - micro_wake_word.stop:

binary_sensor:
  - platform: gpio
    name: "Boot Button"
    pin:
      number: GPIO0
      inverted: true
      mode: INPUT
    on_press:
      - voice_assistant.start:
    on_release:
      - voice_assistant.stop:

  - platform: gpio
    name: "Key Button"
    pin:
      number: GPIO18
      inverted: true
      mode: INPUT
    on_press:
      - switch.toggle: mute_switch

number:
  - platform: template
    name: "TTS Volume"
    id: tts_volume
    icon: mdi:volume-high
    min_value: 0
    max_value: 100
    step: 5
    initial_value: 75
    optimistic: true
    restore_value: true
    set_action:
      then:
        - media_player.volume_set:
            id: speaker_media_player
            volume: !lambda "return x / 100.0;"

Notes

• The display uses an external ESPHome component: kylehase/ESPHome-ST7305-RLCD
• PSRAM (8MB octal) is required for display rendering and audio buffers
• The speaker amplifier must be enabled via GPIO46 for audio output
• The board also has a PCF85063A RTC and a microSD slot, which are not yet supported in this config
• The board has two 8-pin expansion headers (2.54mm pitch)