Sound level from speaker component?

ESPHome
1

I’m looking at this:

but there is only an option to use a microphone input to determine sound level.

My speaker is digital (SPDIF, literally a speaker component).

How do I tell the sound level component to use the audio data being played back through the speaker as a microphone input to measure levels?

This is a prerequisite to build a VU meter (whether internal to the ESP via a MIPI display, or as an output I can push periodically to another device that will do the display), which is my ultimate goal.

Thanks in advance.

2

You could try with physical loop-back (jumper wire) from speaker dout pin to mic din pin.

3

That didn’t work at all. The sound level measurements are all over the place even though I’m playing a known -2.5 dB peak -5.5 dB RMS audio file through the player. Interestingly if the input pin is not connected, the sound level measurements correctly indicate -inf dB

Here is the code I’m using:

i2s_audio:
  - id: i2s_output
    use_legacy: true
  - id: i2s_input
    use_legacy: true

microphone:
  - platform: i2s_audio
    id: external_mic
    adc_type: external
    i2s_din_pin: GPIO4
    sample_rate: 48000
    bits_per_sample: 16bit
    channel: stereo
    i2s_audio_id: i2s_input

sensor:
  - platform: sound_level
    microphone: external_mic
    passive: false
    peak:
      name: "Peak loudness"
    rms:
      name: "RMS loudness"

speaker:
  - platform: i2s_audio
    id: i2s_audio_speaker
    dac_type: external
    i2s_dout_pin: GPIO21
    sample_rate: 48000
    bits_per_sample: 16bit
    buffer_duration: 80ms
    # fill_silence: true
    channel: stereo
    spdif_mode: true
    i2s_audio_id: i2s_output
  # Virtual speakers to combine the announcement and media streams together into one output
  - platform: mixer
    id: mixing_speaker
    output_speaker: i2s_audio_speaker
    num_channels: 2
    source_speakers:
      - id: announcement_mixing_input
        timeout: never
      - id: media_mixing_input
        timeout: never
  - platform: resampler
    id: announcement_resampling_speaker
    output_speaker: announcement_mixing_input
    sample_rate: 48000
    bits_per_sample: 16
  - platform: resampler
    id: media_resampling_speaker
    output_speaker: media_mixing_input
    sample_rate: 48000
    bits_per_sample: 16

media_player:
  - platform: speaker
    buffer_size: 524288
    # task_stack_in_psram: true
    name: Media Player
    codec_support_enabled: true
    internal: false
    announcement_pipeline:
      speaker: announcement_resampling_speaker
      format: FLAC     # FLAC is the least processor intensive codec
      num_channels: 1  # Stereo audio is unnecessary for announcements
      sample_rate: 48000
    media_pipeline:
      speaker: media_resampling_speaker
      format: FLAC     # FLAC is the least processor intensive codec
      num_channels: 2
      sample_rate: 48000