void capturePicture() {
  if (!cam.takePicture())
    client.publish("info", "Failed to snap!");
  else
    client.publish("info", "Picture taken!");

  char length[21];
  uint32_t jpglen = cam.frameLength();

  sprintf(length, "buffer length: %d", jpglen);
  client.publish("info", length);

  byte wCount = 0;  // For counting # of writes
  client.publish("info", "transfer about to begin");
  client.beginPublish("picture", jpglen, false);
  client.publish("info", "after beginPublish");

  while (jpglen > 0) {
    uint8_t* buffer;
    uint8_t bytesToRead = min((uint32_t)16, jpglen);  // change 32 to 64 for a speedup but may not work with all setups!
    buffer = cam.readPicture(bytesToRead);

    client.write(buffer, bytesToRead);

    jpglen -= bytesToRead;
  }

  client.endPublish();
  client.publish("info", "transfer should have ended;");
}

void loop() {
  delay(1000);

  if (count == 5) capturePicture();

  if (!client.connected()) {
    reconnect();
  }

  int multi = analogRead(A2);
  int odor = analogRead(A1);
  int voc = analogRead(A0);

  char name[21];
  sprintf(name, "%d;%d;%d", multi, odor, voc);

  bool pubScss = client.publish("measurement", name);

  count++;
  client.loop();
}

What can be happening here? Something I can further test??

Thanks for advices!

void capturePicture() {
  if (!cam.takePicture())
    client.publish("info", "Failed to snap!");
  else
    client.publish("info", "Picture taken!");

  char length[21];
  uint32_t jpglen = cam.frameLength();

  sprintf(length, "buffer length: %d", jpglen);
  client.publish("info", length);

  byte wCount = 0;  // For counting # of writes
  client.publish("info", "transfer about to begin");
  client.beginPublish("picture", jpglen, false);
  client.publish("info", "after beginPublish");

  while (jpglen > 0) {
    uint8_t* buffer;
    uint8_t bytesToRead = min((uint32_t)16, jpglen);  // change 32 to 64 for a speedup but may not work with all setups!
    buffer = cam.readPicture(bytesToRead);

    client.write(buffer, bytesToRead);

    jpglen -= bytesToRead;
  }

  client.endPublish();
  client.publish("info", "transfer should have ended;");
}

void loop() {
  delay(1000);

  if (count == 5) capturePicture();

  if (!client.connected()) {
    reconnect();
  }

  int multi = analogRead(A2);
  int odor = analogRead(A1);
  int voc = analogRead(A0);

  char name[21];
  sprintf(name, "%d;%d;%d", multi, odor, voc);

  bool pubScss = client.publish("measurement", name);

  count++;
  client.loop();
}

What can be happening here? Something I can further test??

I may have done some things incorrectly here, but this I what I have for publishing image that I read from serial camera to the MQTT broker:

void capturePicture() {
  if (!cam.takePicture())
    client.publish("info", "Failed to snap!");
  else
    client.publish("info", "Picture taken!");

  char length[21];
  uint32_t jpglen = cam.frameLength();

  sprintf(length, "buffer length: %d", jpglen);
  client.publish("info", length);

  byte wCount = 0;  // For counting # of writes
  client.publish("info", "transfer about to begin");
  client.beginPublish("picture", jpglen, false);
  client.publish("info", "after beginPublish");

  while (jpglen > 0) {
    uint8_t* buffer;
    uint8_t bytesToRead = min((uint32_t)16, jpglen);  // change 32 to 64 for a speedup but may not work with all setups!
    buffer = cam.readPicture(bytesToRead);

    client.write(buffer, bytesToRead);

    jpglen -= bytesToRead;
  }

  client.endPublish();
  client.publish("info", "transfer should have ended;");
}

I know the board is working, I am connected to the broker and I can receive messages. In the loop I am reading few sensors and pushing the string into the topic

void loop() {
  delay(1000);

  if (count == 5) capturePicture();

  if (!client.connected()) {
    reconnect();
  }

  int multi = analogRead(A2);
  int odor = analogRead(A1);
  int voc = analogRead(A0);

  char name[21];
  sprintf(name, "%d;%d;%d", multi, odor, voc);

  bool pubScss = client.publish("measurement", name);

  count++;
  client.loop();
}

and all that works fine.

what happens when capturePicture() gets executed is this:

Picture taken!
buffer length: 49048
transfer about to begin

--that's what I see on the topic's subscriber side, then it freezes for about 10secs and then it continues with sending messages from the loop.

So it seems like it never get's pass client.beginPublish("picture", jpglen, false); call. I'm setting PubSubClient's buffer size to client.setBufferSize(10235);

What can be happening here? Something I can further test??

Thanks for advices!

I may have done some things incorrectly here, but this I what I have for publishing image that I read from serial camera to the MQTT broker:

void capturePicture() {
  if (!cam.takePicture())
    client.publish("info", "Failed to snap!");
  else
    client.publish("info", "Picture taken!");

  char length[21];
  uint32_t jpglen = cam.frameLength();

  sprintf(length, "buffer length: %d", jpglen);
  client.publish("info", length);

  byte wCount = 0;  // For counting # of writes
  client.publish("info", "transfer about to begin");
  client.beginPublish("picture", jpglen, false);
  client.publish("info", "after beginPublish");

  while (jpglen > 0) {
    uint8_t* buffer;
    uint8_t bytesToRead = min((uint32_t)16, jpglen);  // change 32 to 64 for a speedup but may not work with all setups!
    buffer = cam.readPicture(bytesToRead);

    client.write(buffer, bytesToRead);

    jpglen -= bytesToRead;
  }

  client.endPublish();
  client.publish("info", "transfer should have ended;");
}

I know the board is working, I am connected to the broker and I can receive messages. In the loop I am reading few sensors and pushing the string into the topic

void loop() {
  delay(1000);

  if (count == 5) capturePicture();

  if (!client.connected()) {
    reconnect();
  }

  int multi = analogRead(A2);
  int odor = analogRead(A1);
  int voc = analogRead(A0);

  char name[21];
  sprintf(name, "%d;%d;%d", multi, odor, voc);

  bool pubScss = client.publish("measurement", name);

  count++;
  client.loop();
}

and all that works fine.

what happens when capturePicture() gets executed is this:

Picture taken!
buffer length: 49048
transfer about to begin

--that's what I see on the topic's subscriber side, then it freezes for about 10secs and then it continues with sending messages from the loop.

So it seems like it never gets past client.beginPublish("picture", jpglen, false); call. I'm setting PubSubClient's buffer size to client.setBufferSize(10235);

What can be happening here? Something I can further test??

Thanks for advices!