esp32-cam arduino编程通过mqtt方式定时上报图

感谢提供清晰的思路，3月15日发布的内容，非常好。

image.png

1、主要思路

esp32-cam定时抓图生成16进制字符串，通过esp32 走mqtt通道上报给emq（参见前文)，python订阅mqtt主题把16进制转成所需图片保存；

2、定时抓图代码

初始化相机，设定jpg格式，精度和大小可自行调整；

void setupCamera() {
  const camera_config_t config = {
    .pin_pwdn     = kCameraPin_PWDN,
    .pin_reset    = kCameraPin_RESET,
    .pin_xclk     = kCameraPin_XCLK,
    .pin_sscb_sda = kCameraPin_SIOD,
    .pin_sscb_scl = kCameraPin_SIOC,
    .pin_d7       = kCameraPin_Y9,
    .pin_d6       = kCameraPin_Y8,
    .pin_d5       = kCameraPin_Y7,
    .pin_d4       = kCameraPin_Y6,
    .pin_d3       = kCameraPin_Y5,
    .pin_d2       = kCameraPin_Y4,
    .pin_d1       = kCameraPin_Y3,
    .pin_d0       = kCameraPin_Y2,
    .pin_vsync    = kCameraPin_VSYNC,
    .pin_href     = kCameraPin_HREF,
    .pin_pclk     = kCameraPin_PCLK,
    .xclk_freq_hz = 20000000,
    .ledc_timer   = LEDC_TIMER_0,
    .ledc_channel = LEDC_CHANNEL_0,
    .pixel_format = PIXFORMAT_JPEG,
    .frame_size   = FRAMESIZE_SVGA,
    .jpeg_quality = 10,
    .fb_count     = 1,
  };

  esp_err_t err = esp_camera_init(&config);
  Serial.printf("esp_camera_init: 0x%x\n", err);

  // sensor_t *s = esp_camera_sensor_get();
  // s->set_framesize(s, FRAMESIZE_QVGA);
}

定时抓图，fb->buf就是16进制图片数据；
时间设定20秒，可自行调整间隔时间长短；

void loop() {

//  抓拍图片
  camera_fb_t *fb = esp_camera_fb_get();
  
  delay(20000);  // [ms]
}

3、通过wifi方式上报mqtt

增加arduino mqtt库；
https://github.com/knolleary/pubsubclient

image.png
初始化mqtt,配置emq的ip地址和端口

void setupMqtt() {
  g_pub_sub_client.setServer(kMqttServerAddress, kMqttServerPort);
}

抓拍上报代码,上报主题为test；

void loop() {
 handleMqtt();
//  抓拍图片
  camera_fb_t *fb = esp_camera_fb_get();
  
  if ( fb ) {
    Serial.printf("width: %d, height: %d, buf: 0x%x, len: %d\n", fb->width, fb->height, fb->buf, fb->len);
    g_pub_sub_client.publish("test", fb->buf, fb->len);
     esp_camera_fb_return(fb);
  }

  delay(20000);  // [ms]
}

5、测试接收数据

image.png

正常接收esp32-cam上报的数据；

6、python 16进制字符转jpg

手工试一下是否可行；复制从emq接受的数据，粘贴到data即可；

import binascii
data="FFD8FFE000104A46494600010101000000000000FFDB0043000A07080908060A0908090B0B0A0C0F19100F0E0E0F1F161712192420262624202322282D3A31282B362B2223324433363B3D4041402730474C463F4B3A3F403EFFDB0043010B0B0B0F0D0F1D10101D3E2923293E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3E3EFFC4001F0000010501010101010100000000000000000102030405060708090A0BFFC400B5100002010303020403050504040000017D01020300041105122131410613516107227114328191A1082342B1C11552D1F02433627282090A161718191A25262728292A3435363738393A434445464748494A535455565758595A636465666768696A737475767778797A838485868788898A92939495969798999AA2A3A4A5A6A7A8A9AAB2B3B4B5B6B7B8B9BAC2C3C4C5C6C7C8C9CAD2D3D4D5D6D7D8D9DAE1E2E3E4E5E6E7E8E9EAF1F2F3F4F5F6F7F8F9FAFFC4001F0100030101010101010101010000000000000102030405060708090A0BFFC400B51100020102040403040705040400010277000102031104052131061241510761711322328108144291A1B1C109233352F0156272D10A162434E125F11718191A262728292A35363738393A434445464748494A535455565758595A636465666768696A737475767778797A82838485868788898A92939495969798999AA29A0558C3140A00754A8A68623A0B4E228573F5AD78A4315C8940AC645A343FB4B03941F9D2AEA01FA2

......(数据太长省略)

FEB59DCAB1FFFD9"
data=data.strip()
data=data.replace(' ', '')
data=data.replace('\n', '')
data = binascii.a2b_hex(data)
with open('image.jpg', 'wb') as image_file:
    image_file.write(data)

查看图片

image.png

可以自行加入python订阅相关的mqtt主题，然后根据子项的id，日期保存图片。
类似/test/1358852，1358852+日期为图片名字。
完整后端思路。

全文完；