Implement INMP441 noise indicator with RGB LED feedback and update project configuration

main/main.c

@@ -1,13 +1,139 @@
-#include <stdio.h>
-#include "freertos/FreeRTOS.h"
-#include "freertos/task.h"
+#include <math.h>
+#include <stdint.h>
+
 #include "driver/gpio.h"
+#include "driver/i2s_std.h"
+#include "esp_err.h"
 #include "esp_log.h"
+#include "freertos/FreeRTOS.h"
 #include "led_strip.h"
-#include "sdkconfig.h"
+
+#define I2S_BCLK_GPIO       GPIO_NUM_3
+#define I2S_WS_GPIO         GPIO_NUM_4
+#define I2S_DATA_GPIO       GPIO_NUM_5
+#define RGB_LED_GPIO        GPIO_NUM_48
+
+#define SAMPLE_RATE_HZ      16000
+#define SAMPLES_PER_READ    256
+#define GREEN_NOISE_RMS     100000.0f
+#define RED_NOISE_RMS       1000000.0f
+#define LED_BRIGHTNESS      64
 
 static const char *TAG = "buzz_detector";
 
-void app_main(void) {
-    println("Hello, ESP32!");
+static led_strip_handle_t init_rgb_led(void)
+{
+    const led_strip_config_t strip_config = {
+        .strip_gpio_num = RGB_LED_GPIO,
+        .max_leds = 1,
+        .led_model = LED_MODEL_WS2812,
+        .color_component_format = LED_STRIP_COLOR_COMPONENT_FMT_GRB,
+        .flags = {
+            .invert_out = false,
+        },
+    };
+    const led_strip_rmt_config_t rmt_config = {
+        .clk_src = RMT_CLK_SRC_DEFAULT,
+        .resolution_hz = 10 * 1000 * 1000,
+        .mem_block_symbols = 64,
+        .flags = {
+            .with_dma = false,
+        },
+    };
+
+    led_strip_handle_t strip = NULL;
+    ESP_ERROR_CHECK(led_strip_new_rmt_device(&strip_config, &rmt_config, &strip));
+    ESP_ERROR_CHECK(led_strip_clear(strip));
+    return strip;
+}
+
+static void update_rgb_led(led_strip_handle_t strip, float rms)
+{
+    float red = 0.0f;
+    float green = 0.0f;
+
+    if (rms < GREEN_NOISE_RMS) {
+        green = LED_BRIGHTNESS * rms / GREEN_NOISE_RMS;
+    } else {
+        float red_fraction = (rms - GREEN_NOISE_RMS) /
+            (RED_NOISE_RMS - GREEN_NOISE_RMS);
+        if (red_fraction > 1.0f) {
+            red_fraction = 1.0f;
+        }
+        red = LED_BRIGHTNESS * red_fraction;
+        green = LED_BRIGHTNESS * (1.0f - red_fraction);
+    }
+
+    ESP_ERROR_CHECK(led_strip_set_pixel(strip, 0, (uint8_t)red,
+                                        (uint8_t)green, 0));
+    ESP_ERROR_CHECK(led_strip_refresh(strip));
+}
+
+static i2s_chan_handle_t init_microphone(void)
+{
+    i2s_chan_handle_t rx_channel = NULL;
+    const i2s_chan_config_t channel_config =
+        I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER);
+    ESP_ERROR_CHECK(i2s_new_channel(&channel_config, NULL, &rx_channel));
+
+    i2s_std_config_t standard_config = {
+        .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(SAMPLE_RATE_HZ),
+        .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(
+            I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_MONO),
+        .gpio_cfg = {
+            .mclk = I2S_GPIO_UNUSED,
+            .bclk = I2S_BCLK_GPIO,
+            .ws = I2S_WS_GPIO,
+            .dout = I2S_GPIO_UNUSED,
+            .din = I2S_DATA_GPIO,
+            .invert_flags = {
+                .mclk_inv = false,
+                .bclk_inv = false,
+                .ws_inv = false,
+            },
+        },
+    };
+    standard_config.slot_cfg.slot_mask = I2S_STD_SLOT_LEFT;
+
+    ESP_ERROR_CHECK(i2s_channel_init_std_mode(rx_channel, &standard_config));
+    ESP_ERROR_CHECK(i2s_channel_enable(rx_channel));
+    return rx_channel;
+}
+
+void app_main(void)
+{
+    led_strip_handle_t rgb_led = init_rgb_led();
+    i2s_chan_handle_t microphone = init_microphone();
+    int32_t samples[SAMPLES_PER_READ];
+    float smoothed_rms = 0.0f;
+    uint32_t log_counter = 0;
+
+    ESP_LOGI(TAG, "INMP441 ready on BCLK=%d, WS=%d, SD=%d; RGB LED on GPIO %d",
+             I2S_BCLK_GPIO, I2S_WS_GPIO, I2S_DATA_GPIO, RGB_LED_GPIO);
+
+    while (true) {
+        size_t bytes_read = 0;
+        ESP_ERROR_CHECK(i2s_channel_read(microphone, samples, sizeof(samples),
+                                         &bytes_read, portMAX_DELAY));
+        const size_t sample_count = bytes_read / sizeof(samples[0]);
+        if (sample_count == 0) {
+            continue;
+        }
+
+        int64_t sum_squares = 0;
+        for (size_t i = 0; i < sample_count; ++i) {
+            // INMP441 provides 24-bit signed samples in the upper bits of each 32-bit slot.
+            const int32_t sample = samples[i] >> 8;
+            sum_squares += (int64_t)sample * sample;
+        }
+
+        const float rms = sqrtf((float)sum_squares / sample_count);
+        smoothed_rms += 0.2f * (rms - smoothed_rms);
+        update_rgb_led(rgb_led, smoothed_rms);
+
+        if (++log_counter == 16) {
+            ESP_LOGI(TAG, "sound RMS: %.0f", smoothed_rms);
+            log_counter = 0;
+        }
+    }
 }