ESP32 AI Object Detector

// ESP32-CAM AI Object Detector - Beginner
// Colour blob detection using RGB565 pixel thresholding
// No ML model required — demonstrates image processing fundamentals

#include "esp_camera.h"

// AI Thinker ESP32-CAM pin map
#define PWDN_GPIO 32
#define RESET_GPIO -1
#define XCLK_GPIO 0
#define SIOD_GPIO 26
#define SIOC_GPIO 27
#define Y9_GPIO 35
#define Y8_GPIO 34
#define Y7_GPIO 39
#define Y6_GPIO 36
#define Y5_GPIO 21
#define Y4_GPIO 19
#define Y3_GPIO 18
#define Y2_GPIO 5
#define VSYNC_GPIO 25
#define HREF_GPIO 23
#define PCLK_GPIO 22

const int LED_PIN = 33;
// Detection threshold: fraction of frame pixels in target range
const float DETECT_THRESHOLD = 0.05; // 5 percent of frame

void initCamera() {
  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer   = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO; config.pin_d1 = Y3_GPIO;
  config.pin_d2 = Y4_GPIO; config.pin_d3 = Y5_GPIO;
  config.pin_d4 = Y6_GPIO; config.pin_d5 = Y7_GPIO;
  config.pin_d6 = Y8_GPIO; config.pin_d7 = Y9_GPIO;
  config.pin_xclk  = XCLK_GPIO; config.pin_pclk  = PCLK_GPIO;
  config.pin_vsync = VSYNC_GPIO; config.pin_href  = HREF_GPIO;
  config.pin_sscb_sda = SIOD_GPIO; config.pin_sscb_scl = SIOC_GPIO;
  config.pin_pwdn  = PWDN_GPIO;  config.pin_reset = RESET_GPIO;
  config.xclk_freq_hz = 20000000;
  config.pixel_format = PIXFORMAT_RGB565;
  config.frame_size   = FRAMESIZE_QVGA; // 320x240
  config.jpeg_quality = 12;
  config.fb_count     = 1;
  esp_camera_init(&config);
}

// Count pixels where red channel dominates (simple fire/orange detection)
float detectOrange(camera_fb_t *fb) {
  uint16_t *pixels = (uint16_t*)fb->buf;
  size_t total = fb->width * fb->height;
  size_t matches = 0;
  for (size_t i = 0; i < total; i++) {
    uint16_t px = pixels[i];
    // RGB565: R=bits 15-11, G=bits 10-5, B=bits 4-0
    uint8_t r = (px >> 11) & 0x1F;
    uint8_t g = (px >> 5)  & 0x3F;
    uint8_t b =  px        & 0x1F;
    // Orange: high red, moderate green, low blue (scaled to 5/6-bit)
    if (r > 20 && g > 15 && g < 40 && b < 8) matches++;
  }
  return (float)matches / total;
}

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  initCamera();
  Serial.println("Colour detector ready.");
}

void loop() {
  camera_fb_t *fb = esp_camera_fb_get();
  if (!fb) { delay(100); return; }
  float ratio = detectOrange(fb);
  esp_camera_fb_return(fb);
  bool detected = ratio > DETECT_THRESHOLD;
  digitalWrite(LED_PIN, detected ? HIGH : LOW);
  Serial.printf("Orange ratio: %.3f  Detected: %sn",
    ratio, detected ? "YES" : "no");
  delay(200);
}