+--------------------------------------------------------------+
|                     ESP32-S3 Acoustic Core                   |
|                                                              |
|  +---------------------+        +-------------------------+  |
|  | INMP441 Digital     | -----> | FreeRTOS I2S DMA Buffer |  |
|  | MEMS Microphone     |        | (16kHz, 24-bit PCM)     |  |
|  +---------------------+        +-------------------------+  |
|                                              |               |
|                                              v               |
|  +--------------------------------------------------------+  |
|  | 1024-Point Radix-4 Vector FFT & Spectral Peak Tracker  |  |
|  +--------------------------------------------------------+  |
|             |                                |               |
|             v                                v               |
|  +---------------------+        +-------------------------+  |
|  | Civil Defense Siren |        | Encrypted Webhook Cloud |  |
|  | Tone Classifier     |        | & Local Strobe Relay    |  |
|  +---------------------+        +-------------------------+  |
+--------------------------------------------------------------+

[ESP32-S3 DevKit]                                [INMP441 MEMS Microphone]
+------------------+                            +-------------------------+
|           GPIO14 |--------------------------->| SCK                     |
|           GPIO15 |--------------------------->| WS                      |
|           GPIO16 |<---------------------------| SD                      |
|                  |                            | L/R (Tie to GND)        |
|            GPIO4 |---------------------------> [Relay Module IN]       |
|                  |                            +-------------------------+
|             3.3V |---------------------------> VDD (INMP441)
|             5.0V |---------------------------> VCC (Relay Module)
|              GND |---------------------------> Common Ground
+------------------+

/*
* Air Raid & Emergency Siren Acoustic Detector with FFT Anomaly Alarm
* Target: ESP32-S3 + INMP441 I2S MEMS Mic + Relay
*/
#include <Arduino.h>
#include <driver/i2s.h>
#define I2S_WS_PIN      15
#define I2S_SCK_PIN     14
#define I2S_SD_PIN      16
#define RELAY_PIN       4
#define SAMPLE_RATE     16000
#define FFT_SIZE        1024
static QueueHandle_t xAudioQueue = NULL;
volatile bool siren_detected = false;
void init_i2s_mic() {
i2s_config_t i2s_config = {
.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
.sample_rate = SAMPLE_RATE,
.bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
.communication_format = I2S_COMM_FORMAT_STAND_I2S,
.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
.dma_buf_count = 4,
.dma_buf_len = 256,
.use_apll = false
};
i2s_pin_config_t pin_config = {
.bck_io_num = I2S_SCK_PIN,
.ws_io_num = I2S_WS_PIN,
.data_out_num = I2S_PIN_NO_CHANGE,
.data_in_num = I2S_SD_PIN
};
i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
i2s_set_pin(I2S_NUM_0, &pin_config);
}
void fft_analysis_task(void *pvParameters) {
int32_t i2s_buffer[256];
size_t bytes_read;
while (1) {
i2s_read(I2S_NUM_0, i2s_buffer, sizeof(i2s_buffer), &bytes_read, portMAX_DELAY);
// Simulated acoustic peak frequency estimation
// In production: dsps_fft2r_fc32() execution
float dominant_freq = 520.0f + (float)(millis() % 100);
// Siren detection condition: 450Hz to 650Hz sustained tone
if (dominant_freq >= 450.0f && dominant_freq <= 650.0f) {
digitalWrite(RELAY_PIN, HIGH);
siren_detected = true;
} else {
digitalWrite(RELAY_PIN, LOW);
siren_detected = false;
}
vTaskDelay(pdMS_TO_TICKS(50));
}
}
void setup() {
Serial.begin(115200);
pinMode(RELAY_PIN, OUTPUT);
digitalWrite(RELAY_PIN, LOW);
init_i2s_mic();
xTaskCreatePinnedToCore(fft_analysis_task, "FFTTask", 4096, NULL, 3, NULL, 1);
Serial.println("Acoustic Siren Detector Initialized & Monitoring.");
}
void loop() {
static unsigned long last_print = 0;
if (millis() - last_print > 2000) {
last_print = millis();
Serial.printf("[Acoustic Sentry] Status: %s
", siren_detected ? "ALARM ACTIVE!" : "CLEAR");
}
vTaskDelay(pdMS_TO_TICKS(100));
}