Can a loop() be empty?

Projects Programming
1

Hi - I have just tried to use the project “iot_3_html_cam_led” in the Sunfounder StarterKit. I uploaded the sketch successfully, after adding my SSID and Password and ensuring the baud rate is set correctly, but I get no output on the serial monitor - (it should output the URL for the webpage to view the camera stream).

I added a simple print statement in the loop() to check the serial output was working, and that worked fine.

However, the loop() is empty, which seems strange to me - is that an error in the sketch? If not, as I understand it, the setup() code runs once, then the loop() code runs, so if the loop() is empty, only the code in the setup() will be the code that does anything: is that correct?

Incidentally; the led connected to pin 14 does not light up when the sketch runs. It is defined as LED_PIN in the setup() line pinMode(LED_PIN, OUTPUT); but I cannot see any code that turns the LED on - perhaps that instruction is buried in a function call somewhere....

The sketch is this one:


/*********
  Permission is hereby granted, free of charge, 
  to any person obtaining a copy of this software and associated documentation files.
  The above copyright notice and this permission 
  notice shall be included in all copies or substantial portions of the Software.
*********/

#include "esp_camera.h"
#include <WiFi.h>
#include "esp_timer.h"
#include "img_converters.h"
#include "Arduino.h"
#include "fb_gfx.h"
#include "soc/soc.h"             // disable brownout problems
#include "soc/rtc_cntl_reg.h"    // disable brownout problems
#include "esp_http_server.h"

// Replace the next variables with your SSID/Password combination
const char* ssid = "**********"; 
const char* password = "**********";

#define PART_BOUNDARY "123456789000000000000987654321"

#define CAMERA_MODEL_AI_THINKER
//#define CAMERA_MODEL_M5STACK_PSRAM
//#define CAMERA_MODEL_M5STACK_WITHOUT_PSRAM
//#define CAMERA_MODEL_M5STACK_PSRAM_B
//#define CAMERA_MODEL_WROVER_KIT

#if defined(CAMERA_MODEL_WROVER_KIT)
  #define PWDN_GPIO_NUM    -1
  #define RESET_GPIO_NUM   -1
  #define XCLK_GPIO_NUM    21
  #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      19
  #define Y4_GPIO_NUM      18
  #define Y3_GPIO_NUM       5
  #define Y2_GPIO_NUM       4
  #define VSYNC_GPIO_NUM   25
  #define HREF_GPIO_NUM    23
  #define PCLK_GPIO_NUM    22

#elif defined(CAMERA_MODEL_M5STACK_PSRAM)
  #define PWDN_GPIO_NUM     -1
  #define RESET_GPIO_NUM    15
  #define XCLK_GPIO_NUM     27
  #define SIOD_GPIO_NUM     25
  #define SIOC_GPIO_NUM     23
  
  #define Y9_GPIO_NUM       19
  #define Y8_GPIO_NUM       36
  #define Y7_GPIO_NUM       18
  #define Y6_GPIO_NUM       39
  #define Y5_GPIO_NUM        5
  #define Y4_GPIO_NUM       34
  #define Y3_GPIO_NUM       35
  #define Y2_GPIO_NUM       32
  #define VSYNC_GPIO_NUM    22
  #define HREF_GPIO_NUM     26
  #define PCLK_GPIO_NUM     21

#elif defined(CAMERA_MODEL_M5STACK_WITHOUT_PSRAM)
  #define PWDN_GPIO_NUM     -1
  #define RESET_GPIO_NUM    15
  #define XCLK_GPIO_NUM     27
  #define SIOD_GPIO_NUM     25
  #define SIOC_GPIO_NUM     23
  
  #define Y9_GPIO_NUM       19
  #define Y8_GPIO_NUM       36
  #define Y7_GPIO_NUM       18
  #define Y6_GPIO_NUM       39
  #define Y5_GPIO_NUM        5
  #define Y4_GPIO_NUM       34
  #define Y3_GPIO_NUM       35
  #define Y2_GPIO_NUM       17
  #define VSYNC_GPIO_NUM    22
  #define HREF_GPIO_NUM     26
  #define PCLK_GPIO_NUM     21

#elif defined(CAMERA_MODEL_AI_THINKER)
  #define PWDN_GPIO_NUM     32
  #define RESET_GPIO_NUM    33
  #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

#elif defined(CAMERA_MODEL_M5STACK_PSRAM_B)
  #define PWDN_GPIO_NUM     -1
  #define RESET_GPIO_NUM    15
  #define XCLK_GPIO_NUM     27
  #define SIOD_GPIO_NUM     22
  #define SIOC_GPIO_NUM     23
  
  #define Y9_GPIO_NUM       19
  #define Y8_GPIO_NUM       36
  #define Y7_GPIO_NUM       18
  #define Y6_GPIO_NUM       39
  #define Y5_GPIO_NUM        5
  #define Y4_GPIO_NUM       34
  #define Y3_GPIO_NUM       35
  #define Y2_GPIO_NUM       32
  #define VSYNC_GPIO_NUM    25
  #define HREF_GPIO_NUM     26
  #define PCLK_GPIO_NUM     21

#else
  #error "Camera model not selected"
#endif

#define LED_PIN    14

static const char* _STREAM_CONTENT_TYPE = "multipart/x-mixed-replace;boundary=" PART_BOUNDARY;
static const char* _STREAM_BOUNDARY = "\r\n--" PART_BOUNDARY "\r\n";
static const char* _STREAM_PART = "Content-Type: image/jpeg\r\nContent-Length: %u\r\n\r\n";

httpd_handle_t camera_httpd = NULL;
httpd_handle_t stream_httpd = NULL;

static const char PROGMEM INDEX_HTML[] = R"rawliteral(
<html>
  <head>
    <title>ESP32-CAM Robot</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
      body { font-family: Arial; text-align: center; margin:0px auto; padding-top: 30px;}
      table { margin-left: auto; margin-right: auto; }
      td { padding: 8 px; }
      .button {
        background-color: #2f4468;
        border: none;
        color: white;
        padding: 10px 20px;
        text-align: center;
        text-decoration: none;
        display: inline-block;
        font-size: 18px;
        margin: 6px 3px;
        cursor: pointer;
        -webkit-touch-callout: none;
        -webkit-user-select: none;
        -khtml-user-select: none;
        -moz-user-select: none;
        -ms-user-select: none;
        user-select: none;
        -webkit-tap-highlight-color: rgba(0,0,0,0);
      }
      img {  width: auto ;
        max-width: 100% ;
        height: auto ; 
        transform: rotate(180deg);
      }
    </style>
  </head>
  <body>
    <h1>ESP32 CAMERA</h1>
    <img src="" id="photo" >
    <table>
      <tr><td align="center"><button class="button" onmousedown="toggleCheckbox('on');" ontouchstart="toggleCheckbox('on');onmouseup="toggleCheckbox('on');" ontouchend="toggleCheckbox('on');">ON</button></td>
      <td align="center"><button class="button" onmousedown="toggleCheckbox('off');" ontouchstart="toggleCheckbox('off');onmouseup="toggleCheckbox('off');" ontouchend="toggleCheckbox('off');">OFF</button></td></tr>
    </table>
   <script>
   function toggleCheckbox(x) {
     var xhr = new XMLHttpRequest();
     xhr.open("GET", "/action?go=" + x, true);
     xhr.send();
   }
   window.onload = document.getElementById("photo").src = window.location.href.slice(0, -1) + ":81/stream";
  </script>
  </body>
</html>
)rawliteral";

static esp_err_t index_handler(httpd_req_t *req){
  httpd_resp_set_type(req, "text/html");
  return httpd_resp_send(req, (const char *)INDEX_HTML, strlen(INDEX_HTML));
}

static esp_err_t stream_handler(httpd_req_t *req){
  camera_fb_t * fb = NULL;
  esp_err_t res = ESP_OK;
  size_t _jpg_buf_len = 0;
  uint8_t * _jpg_buf = NULL;
  char * part_buf[64];

  res = httpd_resp_set_type(req, _STREAM_CONTENT_TYPE);
  if(res != ESP_OK){
    return res;
  }

  while(true){
    fb = esp_camera_fb_get();
    if (!fb) {
      Serial.println("Camera capture failed");
      res = ESP_FAIL;
    } else {
      if(fb->width > 400){
        if(fb->format != PIXFORMAT_JPEG){
          bool jpeg_converted = frame2jpg(fb, 80, &_jpg_buf, &_jpg_buf_len);
          esp_camera_fb_return(fb);
          fb = NULL;
          if(!jpeg_converted){
            Serial.println("JPEG compression failed");
            res = ESP_FAIL;
          }
        } else {
          _jpg_buf_len = fb->len;
          _jpg_buf = fb->buf;
        }
      }
    }
    if(res == ESP_OK){
      size_t hlen = snprintf((char *)part_buf, 64, _STREAM_PART, _jpg_buf_len);
      res = httpd_resp_send_chunk(req, (const char *)part_buf, hlen);
    }
    if(res == ESP_OK){
      res = httpd_resp_send_chunk(req, (const char *)_jpg_buf, _jpg_buf_len);
    }
    if(res == ESP_OK){
      res = httpd_resp_send_chunk(req, _STREAM_BOUNDARY, strlen(_STREAM_BOUNDARY));
    }
    if(fb){
      esp_camera_fb_return(fb);
      fb = NULL;
      _jpg_buf = NULL;
    } else if(_jpg_buf){
      free(_jpg_buf);
      _jpg_buf = NULL;
    }
    if(res != ESP_OK){
      break;
    }
    //Serial.printf("MJPG: %uB\n",(uint32_t)(_jpg_buf_len));
  }
  return res;
}

static esp_err_t cmd_handler(httpd_req_t *req){
  char*  buf;
  size_t buf_len;
  char variable[32] = {0,};
  
  buf_len = httpd_req_get_url_query_len(req) + 1;
  if (buf_len > 1) {
    buf = (char*)malloc(buf_len);
    if(!buf){
      httpd_resp_send_500(req);
      return ESP_FAIL;
    }
    if (httpd_req_get_url_query_str(req, buf, buf_len) == ESP_OK) {
      if (httpd_query_key_value(buf, "go", variable, sizeof(variable)) == ESP_OK) {
      } else {
        free(buf);
        httpd_resp_send_404(req);
        return ESP_FAIL;
      }
    } else {
      free(buf);
      httpd_resp_send_404(req);
      return ESP_FAIL;
    }
    free(buf);
  } else {
    httpd_resp_send_404(req);
    return ESP_FAIL;
  }

  sensor_t * s = esp_camera_sensor_get();
  int res = 0;
  
  if(!strcmp(variable, "on")) {
    Serial.println("ON");
    digitalWrite(LED_PIN, 1);
  }
  else if(!strcmp(variable, "off")) {
    Serial.println("OFF");
    digitalWrite(LED_PIN, 0);
  }
  else {
    res = -1;
  }

  if(res){
    return httpd_resp_send_500(req);
  }

  httpd_resp_set_hdr(req, "Access-Control-Allow-Origin", "*");
  return httpd_resp_send(req, NULL, 0);
}

void startCameraServer(){
  httpd_config_t config = HTTPD_DEFAULT_CONFIG();
  config.server_port = 80;
  httpd_uri_t index_uri = {
    .uri       = "/",
    .method    = HTTP_GET,
    .handler   = index_handler,
    .user_ctx  = NULL
  };

  httpd_uri_t cmd_uri = {
    .uri       = "/action",
    .method    = HTTP_GET,
    .handler   = cmd_handler,
    .user_ctx  = NULL
  };
  httpd_uri_t stream_uri = {
    .uri       = "/stream",
    .method    = HTTP_GET,
    .handler   = stream_handler,
    .user_ctx  = NULL
  };
  if (httpd_start(&camera_httpd, &config) == ESP_OK) {
    httpd_register_uri_handler(camera_httpd, &index_uri);
    httpd_register_uri_handler(camera_httpd, &cmd_uri);
  }
  config.server_port += 1;
  config.ctrl_port += 1;
  if (httpd_start(&stream_httpd, &config) == ESP_OK) {
    httpd_register_uri_handler(stream_httpd, &stream_uri);
  }
}

void setup() {
  WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG, 0); //disable brownout detector
  
  pinMode(LED_PIN, OUTPUT);
  
  Serial.begin(9600);
  Serial.setDebugOutput(false);
  
  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; 
  
  if(psramFound()){
    config.frame_size = FRAMESIZE_VGA;
    config.jpeg_quality = 10;
    config.fb_count = 2;
  } else {
    config.frame_size = FRAMESIZE_SVGA;
    config.jpeg_quality = 12;
    config.fb_count = 1;
  }
  
  // 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;
  }
  // Wi-Fi connection
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  
  Serial.print("Camera Stream Ready! Go to: http://");
  Serial.println(WiFi.localIP());
  
  // Start streaming web server
  startCameraServer();
}

void loop() {
  
}
2

An empty loop is often seen when activities are triggered by interrupts instead of the normal program flow. With RTOS sometimes a small delay in an otherwise empty loop() can be helpful.

3

Indeed it is, circa line 289

  if(!strcmp(variable, "on")) {
    Serial.println("ON");
    digitalWrite(LED_PIN, 1);
  }

No, the camera server runs with callbacks, so there is no code needed in loop(). When a message is received in the server code, it calls a function to handle request.

4

Thanks to all for the rapid replies - very helpful.

As an update: just as an experiment, I placed the code line startCameraServer(); in the loop() and I got the output below repeatedly. So it looks like the camera isn't initialising correctly.

`ELF file SHA256: 39d21cd43

Rebooting…

��?qL�1[!aʄ])9q1!���9!�E (150) cam_hal: cam_dma_config(301): frame buffer malloc failed

E (150) cam_hal: cam_config(390): cam_dma_config failed

E (150) camera: Camera config failed with error 0xffffffff

Camera init failed with error 0xffffffff

assert failed: xQueueSemaphoreTake queue.c:1709 (( pxQueue ))

Backtrace: 0x40082625:0x3ffb1ea0 0x4008cd7d:0x3ffb1ec0 0x400932ca:0x3ffb1ee0 0x4008d552:0x3ffb2010 0x400f87ca:0x3ffb2050 0x400e7d8a:0x3ffb2070 0x400f8d3d:0x3ffb2090 0x400f8d9d:0x3ffb20b0 0x400e6cfd:0x3ffb2100 0x4011040b:0x3ffb2120 0x400d2ac0:0x3ffb2190 0x400d2c6f:0x3ffb2250 0x400d7684:0x3ffb2270 0x4008d9f6:0x3ffb2290

5

Oh no, don't do that. That will try to restart the camera server and cause an error.

6

Understood Bob - I've reverted to the sketch as sent. Any thoughts as to why I am not getting the expected ip address on the serial monitor?

The tutorial instructions says:

  1. You will see a successful WiFi connection message and the assigned IP address in the Serial Monitor.

WiFi connected Camera Stream Ready! Go to: http://192.168.18.77

7

For reference, I believe the tutorial you are following is this one : 2.14 Custom Video Streaming Web Server — SunFounder ESP32 Starter Kit documentation

If it didn't display "Connected" then it didn't connect. You could try changing the code to:

  // Wi-Fi connection
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.println("connecting...");
  }
8

Hi Bob,

The project I am attempting is here:
https://docs.sunfounder.com/projects/esp32-starter-kit/en/latest/arduino/iot_projects/ar_iot_camera_web.html

I would have expected a line of dots a half a second apart whilst it was trying to connect, but I get nothing on the serial monitor. I have changed the code as you suggest, but that didn't change anything, unfortunately (I think that would have generated the word "connecting" every 500mS until a connection was established).

Many thanks for taking time to respond.

9

I would add more print statements in setup(), also check you have the right baud setting. Probably best to leave it as 115200. Those garbage characters in the serial output might contain an error message.

10

@pelso69

Not to be rude but did you ask on that forum? ... Expert Support.

image
image1165×468 34 KB

11

you might want to add some code to loop() to

  • mointor for cmds supporting testing and debugging from the serial monitor, as well as
  • reconnecting if the connection is lost
12

Hi Mike - yes, I have asked there, but my experience to date is that I have not received responses from that forum.

13

As stated in the code at the link you provided:

  // Do nothing. Everything is done in another task by the web server

Not only is the loop() function empty in most well-written code that uses FreeRTOS, I typically delete the task that it runs in:

void loop() {
	vTaskDelete(NULL);
}
14

Thanks for pointing that out - the version I used initially is below, and did not have that comment after the loop() statement.

https://docs.sunfounder.com/projects/esp-cam-kit/en/latest/projects/ar_iot_html_cam_led.html

15

Thanks for the advice above: I have now peppered the sketch with Serial.println() statements, see below, - all starting with TESTING: - and the only one that appears on the serial monitor is the one in the loop(). As expected, and it repeats continuously of course.

There is even a line at the start of setup() which is;
Serial.println("TESTING: Print from setup() ");

...so if that doesn't print out it appears that the setup() is not being run?!

``
/*********
Permission is hereby granted, free of charge,
to any person obtaining a copy of this software and associated documentation files.
The above copyright notice and this permission
notice shall be included in all copies or substantial portions of the Software.
*********/
#include "esp_camera.h"
#include <WiFi.h>
#include "esp_timer.h"
#include "img_converters.h"
#include "Arduino.h"
#include "fb_gfx.h"
#include "soc/soc.h" // disable brownout problems
#include "soc/rtc_cntl_reg.h" // disable brownout problems
#include "esp_http_server.h"

// Replace the next variables with your SSID/Password combination
const char* ssid = "SKY91GIX-2.4Ghz"; // Elmtree House wifi
const char* password = "4ND3aJPIyTId";// Elmtree House wifi password

#define PART_BOUNDARY "123456789000000000000987654321"

#define CAMERA_MODEL_AI_THINKER
//#define CAMERA_MODEL_M5STACK_PSRAM
//#define CAMERA_MODEL_M5STACK_WITHOUT_PSRAM
//#define CAMERA_MODEL_M5STACK_PSRAM_B
//#define CAMERA_MODEL_WROVER_KIT

#if defined(CAMERA_MODEL_WROVER_KIT)
#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 21
#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 19
#define Y4_GPIO_NUM 18
#define Y3_GPIO_NUM 5
#define Y2_GPIO_NUM 4
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 23
#define PCLK_GPIO_NUM 22

#elif defined(CAMERA_MODEL_M5STACK_PSRAM)
#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM 15
#define XCLK_GPIO_NUM 27
#define SIOD_GPIO_NUM 25
#define SIOC_GPIO_NUM 23

#define Y9_GPIO_NUM 19
#define Y8_GPIO_NUM 36
#define Y7_GPIO_NUM 18
#define Y6_GPIO_NUM 39
#define Y5_GPIO_NUM 5
#define Y4_GPIO_NUM 34
#define Y3_GPIO_NUM 35
#define Y2_GPIO_NUM 32
#define VSYNC_GPIO_NUM 22
#define HREF_GPIO_NUM 26
#define PCLK_GPIO_NUM 21

#elif defined(CAMERA_MODEL_M5STACK_WITHOUT_PSRAM)
#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM 15
#define XCLK_GPIO_NUM 27
#define SIOD_GPIO_NUM 25
#define SIOC_GPIO_NUM 23

#define Y9_GPIO_NUM 19
#define Y8_GPIO_NUM 36
#define Y7_GPIO_NUM 18
#define Y6_GPIO_NUM 39
#define Y5_GPIO_NUM 5
#define Y4_GPIO_NUM 34
#define Y3_GPIO_NUM 35
#define Y2_GPIO_NUM 17
#define VSYNC_GPIO_NUM 22
#define HREF_GPIO_NUM 26
#define PCLK_GPIO_NUM 21

#elif defined(CAMERA_MODEL_AI_THINKER)
#define PWDN_GPIO_NUM 32
#define RESET_GPIO_NUM 33
#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

#elif defined(CAMERA_MODEL_M5STACK_PSRAM_B)
#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM 15
#define XCLK_GPIO_NUM 27
#define SIOD_GPIO_NUM 22
#define SIOC_GPIO_NUM 23

#define Y9_GPIO_NUM 19
#define Y8_GPIO_NUM 36
#define Y7_GPIO_NUM 18
#define Y6_GPIO_NUM 39
#define Y5_GPIO_NUM 5
#define Y4_GPIO_NUM 34
#define Y3_GPIO_NUM 35
#define Y2_GPIO_NUM 32
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 26
#define PCLK_GPIO_NUM 21

#else
#error "Camera model not selected"
#endif

#define LED_PIN 14

static const char* _STREAM_CONTENT_TYPE = "multipart/x-mixed-replace;boundary=" PART_BOUNDARY;
static const char* _STREAM_BOUNDARY = "\r\n--" PART_BOUNDARY "\r\n";
static const char* _STREAM_PART = "Content-Type: image/jpeg\r\nContent-Length: %u\r\n\r\n";

httpd_handle_t camera_httpd = NULL;
httpd_handle_t stream_httpd = NULL;

static const char PROGMEM INDEX_HTML[] = R"rawliteral(

ESP32-CAM Robot body { font-family: Arial; text-align: center; margin:0px auto; padding-top: 30px;} table { margin-left: auto; margin-right: auto; } td { padding: 8 px; } .button { background-color: #2f4468; border: none; color: white; padding: 10px 20px; text-align: center; text-decoration: none; display: inline-block; font-size: 18px; margin: 6px 3px; cursor: pointer; -webkit-touch-callout: none; -webkit-user-select: none; -khtml-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; -webkit-tap-highlight-color: rgba(0,0,0,0); } img { width: auto ; max-width: 100% ; height: auto ; transform: rotate(180deg); }

ESP32 CAMERA

ON OFF
)rawliteral";

static esp_err_t index_handler(httpd_req_t *req){
httpd_resp_set_type(req, "text/html");
return httpd_resp_send(req, (const char *)INDEX_HTML, strlen(INDEX_HTML));
}

static esp_err_t stream_handler(httpd_req_t *req){
camera_fb_t * fb = NULL;
esp_err_t res = ESP_OK;
size_t _jpg_buf_len = 0;
uint8_t * _jpg_buf = NULL;
char * part_buf[64];

res = httpd_resp_set_type(req, _STREAM_CONTENT_TYPE);
if(res != ESP_OK){
return res;
}

while(true){
fb = esp_camera_fb_get();
if (!fb) {
Serial.println("Camera capture failed");
res = ESP_FAIL;
} else {
if(fb->width > 400){
if(fb->format != PIXFORMAT_JPEG){
bool jpeg_converted = frame2jpg(fb, 80, &_jpg_buf, &_jpg_buf_len);
esp_camera_fb_return(fb);
fb = NULL;
if(!jpeg_converted){
Serial.println("JPEG compression failed");
res = ESP_FAIL;
}
} else {
_jpg_buf_len = fb->len;
_jpg_buf = fb->buf;
}
}
}
if(res == ESP_OK){
size_t hlen = snprintf((char *)part_buf, 64, _STREAM_PART, _jpg_buf_len);
res = httpd_resp_send_chunk(req, (const char *)part_buf, hlen);
}
if(res == ESP_OK){
res = httpd_resp_send_chunk(req, (const char *)_jpg_buf, _jpg_buf_len);
}
if(res == ESP_OK){
res = httpd_resp_send_chunk(req, _STREAM_BOUNDARY, strlen(_STREAM_BOUNDARY));
}
if(fb){
esp_camera_fb_return(fb);
fb = NULL;
_jpg_buf = NULL;
} else if(_jpg_buf){
free(_jpg_buf);
_jpg_buf = NULL;
}
if(res != ESP_OK){
break;
}
//Serial.printf("MJPG: %uB\n",(uint32_t)(_jpg_buf_len));
}
return res;
}

static esp_err_t cmd_handler(httpd_req_t req){
char buf;
size_t buf_len;
char variable[32] = {0,};

buf_len = httpd_req_get_url_query_len(req) + 1;
Serial.println("TESTING: Print from line 262 of code");
if (buf_len > 1) {
buf = (char*)malloc(buf_len);
if(!buf){
httpd_resp_send_500(req);
return ESP_FAIL;
}
if (httpd_req_get_url_query_str(req, buf, buf_len) == ESP_OK) {
if (httpd_query_key_value(buf, "go", variable, sizeof(variable)) == ESP_OK) {
} else {
free(buf);
httpd_resp_send_404(req);
return ESP_FAIL;
}
} else {
free(buf);
httpd_resp_send_404(req);
return ESP_FAIL;
}
free(buf);
} else {
httpd_resp_send_404(req);
return ESP_FAIL;
}

sensor_t * s = esp_camera_sensor_get();
int res = 0;

if(!strcmp(variable, "on")) {
Serial.println("ON");
digitalWrite(LED_PIN, 1);
}
else if(!strcmp(variable, "off")) {
Serial.println("OFF");
digitalWrite(LED_PIN, 0);
}
else {
res = -1;
}

if(res){
return httpd_resp_send_500(req);
}

httpd_resp_set_hdr(req, "Access-Control-Allow-Origin", "*");
return httpd_resp_send(req, NULL, 0);
}

void startCameraServer(){
Serial.println("TESTING: Print from startCameraServer ");
httpd_config_t config = HTTPD_DEFAULT_CONFIG();
config.server_port = 80;
httpd_uri_t index_uri = {
.uri = "/",
.method = HTTP_GET,
.handler = index_handler,
.user_ctx = NULL
};

httpd_uri_t cmd_uri = {
.uri = "/action",
.method = HTTP_GET,
.handler = cmd_handler,
.user_ctx = NULL
};
httpd_uri_t stream_uri = {
.uri = "/stream",
.method = HTTP_GET,
.handler = stream_handler,
.user_ctx = NULL
};
if (httpd_start(&camera_httpd, &config) == ESP_OK) {
httpd_register_uri_handler(camera_httpd, &index_uri);
httpd_register_uri_handler(camera_httpd, &cmd_uri);
}
config.server_port += 1;
config.ctrl_port += 1;
if (httpd_start(&stream_httpd, &config) == ESP_OK) {
httpd_register_uri_handler(stream_httpd, &stream_uri);
}
}

void setup() {
Serial.println("TESTING: Print from setup() ");
WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG, 0); //disable brownout detector

pinMode(LED_PIN, OUTPUT);

Serial.begin(115200);
Serial.setDebugOutput(false);

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;

if(psramFound()){
config.frame_size = FRAMESIZE_VGA;
config.jpeg_quality = 10;
config.fb_count = 2;
} else {
config.frame_size = FRAMESIZE_SVGA;
config.jpeg_quality = 12;
config.fb_count = 1;
}

// Camera init
esp_err_t err = esp_camera_init(&config);
Serial.println("TESTING: Print from camera init function");
if (err != ESP_OK) {
Serial.printf("Camera init failed with error 0x%x", err);
return;
}
// Wi-Fi connection

//
WiFi.begin(ssid, password);
Serial.println("TESTING: Print from wifi.begin");
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.println(".");
}
Serial.println("");
Serial.println("WiFi connected");

Serial.print("Camera Stream Ready! Go to: http://");
Serial.println(WiFi.localIP());

// Start streaming web server
//startCameraServer();
}

void loop() {
Serial.println("TESTING: Print from loop");
}

16

You print before Serial.begin();

17

Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'

Use code tags (the < CODE/ > icon above the compose window) to make it easier to read and copy for examination

https://forum.arduino.cc/t/how-to-get-the-best-out-of-this-forum

Please post your sketch, using code tags when you do

Posting your code using code tags prevents parts of it being interpreted as HTML coding and makes it easier to copy for examination

In my experience the easiest way to tidy up the code and add the code tags is as follows

Start by tidying up your code by using Tools/Auto Format in the IDE to make it easier to read. Then use Edit/Copy for Forum and paste what was copied in a new reply. Code tags will have been added to the code to make it easy to read in the forum thus making it easier to provide help.

18

Hi HeliBob - I did use code tags, and always do; the first one is at the beginning of the code - but perhaps the last one was deleted in error. Apologies.

19

Please edit your post and add the code tags

In my experience the easiest way to tidy up the code and add the code tags is as follows

Start by tidying up your code by using Tools/Auto Format in the IDE to make it easier to read. Then use Edit/Copy for Forum and paste what was copied in a forum reply. Code tags will have been added to the code to make it easy to read in the forum thus making it easier to provide help.

20

My thanks to MikeDB for spotting the error of printing before Serial.begin().

I've corrected that, and I now do get the "TESTING: Print from setup()" message, plus "TESTING: Print from camera init function" message.

The output is below, and there is definitely something wrong with the camera initialisation. I have tried physically dismounting and re-mounting the camera module, but with no joy. From my novice perspective, it appears to be something to do with the allocation of memory?? The line "frame buffer malloc failed" is pointing me there...

Serial output is as follows:

ets Jul 29 2019 12:21:46

rst:0x1 (POWERON_RESET),boot:0x12 (SPI_FAST_FLASH_BOOT)

configsip: 0, SPIWP:0xee

clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00

mode:DIO, clock div:1

load:0x3fff0030,len:4916

load:0x40078000,len:16436

load:0x40080400,len:4

ho 8 tail 4 room 4

load:0x40080404,len:3524

entry 0x400805b8

TESTING: Print from setup()

E (150) cam_hal: cam_dma_config(301): frame buffer malloc failed

E (150) cam_hal: cam_config(390): cam_dma_config failed

E (150) camera: Camera config failed with error 0xffffffff

TESTING: Print from camera init function

Camera init failed with error 0xffffffff

TESTING: Print from loop