M5stack atom echo sound level meter

boards/m5stack-atom-echo/demo.yaml

@@ -1,12 +1,9 @@
 # Copyright 2025 Vinicius Fortuna
-# SPDX-License-Identifier: 	Apache-2.0
+# SPDX-License-Identifier: Apache-2.0
 
-# This demo exercises the button, LED, IR transmitter, speaker and microphone.
-# When the button is pressed, it will:
-# - Toggle the LED
-# - Send an IR command
-# - Play a tone on the speaker
-# The microphone is used by the VAD sensor, which logs when it detects speech.
+# This demo exercises the microphone as an Analog Sound Level Meter.
+# It continuously measures the ambient noise level and sets the light
+# brightness to match the sound level.
 
 packages:
   board: !include ./board.yaml
@@ -17,22 +14,35 @@ esphome:
 
 logger:
 
-binary_sensor:
-  - id: !extend echo_button
-    on_release:
-      - light.toggle:
-          id: echo_led
-          transition_length: 0.5s
-      - remote_transmitter.transmit_nec:
-          address: 0x1234
-          command: 0x5678
-      - rtttl.play:
-          id: rtttl_player
-          rtttl: scale_up:d=32,o=5,b=100:c,c#,d#,e,f#,g#,a#,b
-      # Work around RTTTL player getting stuck after first play.
-      # See https://github.com/esphome/esphome/issues/10312
-      - lambda: |-
-          id(rtttl_player).enable_loop();
+microphone:
+  - id: !extend echo_microphone
+    # Without this, the sound level is squished in a narrow range
+    # aroung -30 dB.
+    correct_dc_offset: true
+
+sensor:
+  - id: sound_level_sensor
+    platform: sound_level
+    microphone: echo_microphone
+    passive: false
+    measurement_duration: 50ms
+    rms:
+      name: "Sound Level"
+      on_value:
+        then:
+          - light.turn_on:
+              id: echo_led
+              brightness: !lambda |-
+                // The sound level is in dB, from approx -80 (quiet) to 0 (loud).
+                // Map it to a brightness from 0.0 to 1.0.
+                // We'll use a range of -60 to 0 dB.
+                const float db_min = -60.0;
+                const float db_max = -25.0;
+                float brightness = (x - db_min) / (db_max - db_min);
+                // Clamp to the valid range
+                if (brightness < 0.0) brightness = 0.0;
+                if (brightness > 1.0) brightness = 1.0;
+                return brightness;
 
 rtttl:
   - id: rtttl_player
@@ -41,3 +51,19 @@ rtttl:
     on_finished_playback:
       then:
         - logger.log: Finished playing RTTTL tune.
+
+binary_sensor:
+  - id: !extend echo_button
+    on_release:
+      - remote_transmitter.transmit_nec:
+          address: 0x1234
+          command: 0x5678
+          # yamllint disable-line rule:comments-indentation
+      # TODO: Make this work with the microphone.
+      # - rtttl.play:
+      #     id: rtttl_player
+      #     rtttl: scale_up:d=32,o=5,b=100:c,c#,d#,e,f#,g#,a#,b
+      # # Work around RTTTL player getting stuck after first play.
+      # # See https://github.com/esphome/esphome/issues/10312
+      # - lambda: |-
+      #     id(rtttl_player).enable_loop();