ESP32-CAM的X种用法

        esp32系列是高性价比物联网节点设备的代表，速度够快，自带WIFI又可以使用Arduino IDE编程，最近试用了一种带有OV2640摄像头的ESP32-CAM只要很简单地设置就可以做很多种工作，以下是试验记录。

        Arduino IDE要在首选项中在其他开发板管理器地址中填入https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json，再去开发板管理器界面中找到ESP32，点击安装后才能使用ESP32系列单片机。注意要联网才能安装。

• 用作延时相机

  #include "esp_camera.h"
  #include "FS.h"                // SD Card ESP32
  #include "SD_MMC.h"            // SD Card ESP32
  #include "soc/soc.h"           // Disable brownout problems
  #include "soc/rtc_cntl_reg.h"  // Disable brownout problems
  #include "driver/rtc_io.h"
  #include <WiFi.h>
  #include "time.h"
  
  
  // REPLACE WITH YOUR NETWORK CREDENTIALS
  const char* ssid = "XXXXXX";
  const char* password = "XXXXXX";
  
  
  // REPLACE WITH YOUR TIMEZONE STRING: https://github.com/nayarsystems/posix_tz_db/blob/master/zones.csv
  String myTimezone ="CST-8";
  
  
  // Pin definition for CAMERA_MODEL_AI_THINKER
  // Change pin definition if you're using another ESP32 camera module
  #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
  
  
  // Stores the camera configuration parameters
  camera_config_t config;
  
  
  // Initializes the camera
  void configInitCamera(){
  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; //YUV422,GRAYSCALE,RGB565,JPEG
  config.grab_mode = CAMERA_GRAB_LATEST;
  
  
  // Select lower framesize if the camera doesn't support PSRAM
  if(psramFound()){
    config.frame_size = FRAMESIZE_UXGA; // FRAMESIZE_ + QVGA|CIF|VGA|SVGA|XGA|SXGA|UXGA
    config.jpeg_quality = 5; //0-63 lower number means higher quality
    config.fb_count = 1;
  } else {
    config.frame_size = FRAMESIZE_UXGA;
    config.jpeg_quality = 5;
    config.fb_count = 1;
  }
  
  // Initialize the Camera
  esp_err_t err = esp_camera_init(&config);
  if (err != ESP_OK) {
    Serial.printf("Camera init failed with error 0x%x", err);
    return;
  }
  }
  
  
  // Connect to wifi
  void  initWiFi(){
  WiFi.begin(ssid, password);
  Serial.println("Connecting Wifi");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }
  }
  
  
  // Function to set timezone
  void setTimezone(String timezone){
  Serial.printf("  Setting Timezone to %s\n",timezone.c_str());
  setenv("TZ",timezone.c_str(),1);  //  Now adjust the TZ.  Clock settings are adjusted to show the new local time
  tzset();
  }
  
  
  // Connect to NTP server and adjust timezone
  void initTime(String timezone){
  struct tm timeinfo;
  Serial.println("Setting up time");
  configTime(0, 0, "pool.ntp.org");    // First connect to NTP server, with 0 TZ offset
  if(!getLocalTime(&timeinfo)){
    Serial.println(" Failed to obtain time");
    return;
  }
  Serial.println("Got the time from NTP");
  // Now we can set the real timezone
  setTimezone(timezone);
  }
  
  
  // Get the picture filename based on the current ime
  String getPictureFilename(){
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){
    Serial.println("Failed to obtain time");
    return "";
  }
  char timeString[20];
  strftime(timeString, sizeof(timeString), "%Y-%m-%d_%H-%M-%S", &timeinfo);
  Serial.println(timeString);
  String filename = "/picture_" + String(timeString) +".jpg";
  return filename; 
  }
  
  
  // Initialize the micro SD card
  void initMicroSDCard(){
  // Start Micro SD card
  Serial.println("Starting SD Card");
  if(!SD_MMC.begin()){
    Serial.println("SD Card Mount Failed");
    return;
  }
  uint8_t cardType = SD_MMC.cardType();
  if(cardType == CARD_NONE){
    Serial.println("No SD Card attached");
    return;
  }
  }
  
  
  // Take photo and save to microSD card
  void takeSavePhoto(){
  // Take Picture with Camera
  camera_fb_t * fb = esp_camera_fb_get();
  
  //Uncomment the following lines if you're getting old pictures
  //esp_camera_fb_return(fb); // dispose the buffered image
  //fb = NULL; // reset to capture errors
  //fb = esp_camera_fb_get();
  
  if(!fb) {
    Serial.println("Camera capture failed");
    delay(1000);
    ESP.restart();
  }
  
  
  // Path where new picture will be saved in SD Card
  String path = getPictureFilename();
  Serial.printf("Picture file name: %s\n", path.c_str());
  
  // Save picture to microSD card
  fs::FS &fs = SD_MMC; 
  File file = fs.open(path.c_str(),FILE_WRITE);
  if(!file){
    Serial.printf("Failed to open file in writing mode");
  } 
  else {
    file.write(fb->buf, fb->len); // payload (image), payload length
    Serial.printf("Saved: %s\n", path.c_str());
  }
  file.close();
  esp_camera_fb_return(fb); 
  }
  
  
  void setup() {
  WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG, 0); // disable brownout detector
  
  
  Serial.begin(115200);
  delay(2000);
  
  
  // Initialize Wi-Fi
  initWiFi();
  // Initialize time with timezone
  initTime(myTimezone);    
  // Initialize the camera  
  Serial.print("Initializing the camera module...");
  configInitCamera();
  Serial.println("Ok!");
  // Initialize MicroSD
  Serial.print("Initializing the MicroSD card module... ");
  initMicroSDCard();
  }
  
  
  void loop() {    
  // Take and Save Photo
  takeSavePhoto();
  delay(60000);
  }

          在程序中修改SSID、PASSWORD，myTimezone设置时区字符串，在https://github.com/nayarsystems/posix_tz_db/blob/master/zones.csv中查找到属于当地的时区字符串；config.frame_size设置拍摄分辨率，config.jpeg_quality设置图像质量，0~63，数字越小图像质量越高，但有可能造成图像拍摄出现问题。loop()中delay()函数内是延时时间。
          图像质量实在差劲，最高分辨率UXGA下图像质量设置为0时所拍照片偶有撕裂现象，我一般设置为5。模块上电后按一下reset键，可以确保系统正常工作。

• 用作网络摄影机

  #include "esp_camera.h"
  #include <WiFi.h>
  
  //
  // WARNING!!! PSRAM IC required for UXGA resolution and high JPEG quality
  //            Ensure ESP32 Wrover Module or other board with PSRAM is selected
  //            Partial images will be transmitted if image exceeds buffer size
  //
  //            You must select partition scheme from the board menu that has at least 3MB APP space.
  //            Face Recognition is DISABLED for ESP32 and ESP32-S2, because it takes up from 15 
  //            seconds to process single frame. Face Detection is ENABLED if PSRAM is enabled as well
  
  // ===================
  // Select camera model
  // ===================
  //#define CAMERA_MODEL_WROVER_KIT // Has PSRAM
  //#define CAMERA_MODEL_ESP_EYE // Has PSRAM
  //#define CAMERA_MODEL_ESP32S3_EYE // Has PSRAM
  //#define CAMERA_MODEL_M5STACK_PSRAM // Has PSRAM
  //#define CAMERA_MODEL_M5STACK_V2_PSRAM // M5Camera version B Has PSRAM
  //#define CAMERA_MODEL_M5STACK_WIDE // Has PSRAM
  //#define CAMERA_MODEL_M5STACK_ESP32CAM // No PSRAM
  //#define CAMERA_MODEL_M5STACK_UNITCAM // No PSRAM
  #define CAMERA_MODEL_AI_THINKER // Has PSRAM
  //#define CAMERA_MODEL_TTGO_T_JOURNAL // No PSRAM
  //#define CAMERA_MODEL_XIAO_ESP32S3 // Has PSRAM
  // ** Espressif Internal Boards **
  //#define CAMERA_MODEL_ESP32_CAM_BOARD
  //#define CAMERA_MODEL_ESP32S2_CAM_BOARD
  //#define CAMERA_MODEL_ESP32S3_CAM_LCD
  //#define CAMERA_MODEL_DFRobot_FireBeetle2_ESP32S3 // Has PSRAM
  //#define CAMERA_MODEL_DFRobot_Romeo_ESP32S3 // Has PSRAM
  #include "camera_pins.h"
  
  // ===========================
  // Enter your WiFi credentials
  // ===========================
  const char* ssid = "XXXXXX";
  const char* password = "XXXXXX";
  
  void startCameraServer();
  void setupLedFlash(int pin);
  
  void setup() {
  Serial.begin(115200);
  Serial.setDebugOutput(true);
  Serial.println();
  
  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_sccb_sda = SIOD_GPIO_NUM;
  config.pin_sccb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn = PWDN_GPIO_NUM;
  config.pin_reset = RESET_GPIO_NUM;
  config.xclk_freq_hz = 20000000;
  config.frame_size = FRAMESIZE_UXGA;
  config.pixel_format = PIXFORMAT_JPEG; // for streaming
  //config.pixel_format = PIXFORMAT_RGB565; // for face detection/recognition
  config.grab_mode = CAMERA_GRAB_WHEN_EMPTY;
  config.fb_location = CAMERA_FB_IN_PSRAM;
  config.jpeg_quality = 5;
  config.fb_count = 1;
  
  // if PSRAM IC present, init with UXGA resolution and higher JPEG quality
  //                      for larger pre-allocated frame buffer.
  if(config.pixel_format == PIXFORMAT_JPEG){
    if(psramFound()){
      config.jpeg_quality = 5;
      config.fb_count = 2;
      config.grab_mode = CAMERA_GRAB_LATEST;
    } else {
      // Limit the frame size when PSRAM is not available
      config.frame_size = FRAMESIZE_SVGA;
      config.fb_location = CAMERA_FB_IN_DRAM;
    }
  } else {
    // Best option for face detection/recognition
    config.frame_size = FRAMESIZE_240X240;
  #if CONFIG_IDF_TARGET_ESP32S3
    config.fb_count = 2;
  #endif
  }
  
  #if defined(CAMERA_MODEL_ESP_EYE)
  pinMode(13, INPUT_PULLUP);
  pinMode(14, INPUT_PULLUP);
  #endif
  
  // camera init
  esp_err_t err = esp_camera_init(&config);
  if (err != ESP_OK) {
    Serial.printf("Camera init failed with error 0x%x", err);
    return;
  }
  
  sensor_t * s = esp_camera_sensor_get();
  // initial sensors are flipped vertically and colors are a bit saturated
  if (s->id.PID == OV3660_PID) {
    s->set_vflip(s, 1); // flip it back
    s->set_brightness(s, 1); // up the brightness just a bit
    s->set_saturation(s, -2); // lower the saturation
  }
  // drop down frame size for higher initial frame rate
  if(config.pixel_format == PIXFORMAT_JPEG){
    s->set_framesize(s, FRAMESIZE_QVGA);
  }
  
  #if defined(CAMERA_MODEL_M5STACK_WIDE) || defined(CAMERA_MODEL_M5STACK_ESP32CAM)
  s->set_vflip(s, 1);
  s->set_hmirror(s, 1);
  #endif
  
  #if defined(CAMERA_MODEL_ESP32S3_EYE)
  s->set_vflip(s, 1);
  #endif
  
  // Setup LED FLash if LED pin is defined in camera_pins.h
  #if defined(LED_GPIO_NUM)
  setupLedFlash(LED_GPIO_NUM);
  #endif
  
  WiFi.begin(ssid, password);
  WiFi.setSleep(false);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  
  startCameraServer();
  
  Serial.print("Camera Ready! Use 'http://");
  Serial.print(WiFi.localIP());
  Serial.println("' to connect");
  }
  
  void loop() {
  // Do nothing. Everything is done in another task by the web server
  delay(10000);
  }

          在程序中修改SSID、PASSWORD，上传后打开串口监视器，按rst键，看模块IP地址，在浏览器中输入IP地址就进入网络摄像头界面，点Start Stream开始摄像头网络直播。各种参数可以在浏览器界面进行设置。
  

• 人脸检测和人脸识别

          上面网络摄像头界面左边栏有人脸检测和人脸识别功能，把分辨率调整到320*240时可以开启，此时可以自动识别画面中出现的人脸，还可点击enroll face键预存需要识别的人脸。

        本记录将持续更新。