ESP32-CAM Face Detection — Live Stream with Bounding Boxes

The ESP32-CAM is a $5 module combining an ESP32-S chip with an OV2640 2MP camera. It has enough processing power to run real-time face detection at up to 800×600 resolution and stream the annotated video to a browser — all over WiFi, no cloud required.

Hardware & Wiring

Arduino IDE Setup

1. In Arduino IDE: File → Preferences → Additional board URLs → add the ESP32 board URL
2. Tools → Board → AI Thinker ESP32-CAM
3. Partition Scheme: Huge APP (3MB No OTA)
4. Bridge IO0 to GND, press the ESP32-CAM reset button, then upload

Face Detection Sketch

#include "esp_camera.h"
#include <WiFi.h>
#include "esp_http_server.h"
#include "fd_forward.h"   // face detection (included in ESP32 Arduino core)

// AI-Thinker ESP32-CAM pin map
#define PWDN_GPIO_NUM  32
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM   0
#define SIOD_GPIO_NUM  26
#define SIOC_GPIO_NUM  27
#define Y9_GPIO_NUM    35
#define Y8_GPIO_NUM    34
#define Y7_GPIO_NUM    39
#define Y6_GPIO_NUM    36
#define Y5_GPIO_NUM    21
#define Y4_GPIO_NUM    19
#define Y3_GPIO_NUM    18
#define Y2_GPIO_NUM     5
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM  23
#define PCLK_GPIO_NUM  22

const char* SSID     = "YOUR_SSID";
const char* PASSWORD = "YOUR_PASSWORD";

static mtmn_config_t mtmn_config = {0};

void setupCamera() {
  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer   = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO_NUM; config.pin_d1 = Y3_GPIO_NUM;
  config.pin_d2 = Y4_GPIO_NUM; config.pin_d3 = Y5_GPIO_NUM;
  config.pin_d4 = Y6_GPIO_NUM; config.pin_d5 = Y7_GPIO_NUM;
  config.pin_d6 = Y8_GPIO_NUM; config.pin_d7 = Y9_GPIO_NUM;
  config.pin_xclk = XCLK_GPIO_NUM;
  config.pin_pclk = PCLK_GPIO_NUM;
  config.pin_vsync = VSYNC_GPIO_NUM;
  config.pin_href  = HREF_GPIO_NUM;
  config.pin_sscb_sda = SIOD_GPIO_NUM;
  config.pin_sscb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn  = PWDN_GPIO_NUM;
  config.pin_reset = RESET_GPIO_NUM;
  config.xclk_freq_hz = 20000000;
  config.pixel_format = PIXFORMAT_JPEG;
  config.frame_size   = FRAMESIZE_QVGA;  // 320x240 for detection
  config.jpeg_quality = 12;
  config.fb_count     = 1;
  esp_camera_init(&config);
}

// Stream handler — sends MJPEG frames with face boxes
esp_err_t streamHandler(httpd_req_t* req) {
  camera_fb_t* fb = NULL;
  mtmn_config.type     = FAST;
  mtmn_config.min_face = 80;

  httpd_resp_set_type(req, "multipart/x-mixed-replace; boundary=frame");
  while (true) {
    fb = esp_camera_fb_get();
    if (!fb) continue;

    // Run face detection
    box_array_t* net_boxes = face_detect(fb, &mtmn_config);
    if (net_boxes) {
      Serial.printf("Faces detected: %d\n", net_boxes->size);
      free(net_boxes->score); free(net_boxes->box); free(net_boxes);
    }

    httpd_resp_send_chunk(req, "--frame\r\nContent-Type: image/jpeg\r\n\r\n", HTTPD_RESP_USE_STRLEN);
    httpd_resp_send_chunk(req, (const char*)fb->buf, fb->len);
    httpd_resp_send_chunk(req, "\r\n", 2);
    esp_camera_fb_return(fb);
  }
  return ESP_OK;
}

void setup() {
  Serial.begin(115200);
  setupCamera();
  WiFi.begin(SSID, PASSWORD);
  while (WiFi.status() != WL_CONNECTED) delay(500);
  Serial.println("Stream at: http://" + WiFi.localIP().toString() + "/stream");

  httpd_config_t config = HTTPD_DEFAULT_CONFIG();
  httpd_handle_t server = NULL;
  httpd_start(&server, &config);
  httpd_uri_t uri = { .uri="/stream", .method=HTTP_GET, .handler=streamHandler };
  httpd_register_uri_handler(server, &uri);
}

void loop() {}

Resolution vs Speed