CODEWITHSUNDEEP
arduinoxbee
Chandra
Chandra

Reputation: 37

SD card image transfer using xbee

I trying to read SD card image from arduino (20KB - JPEG -using SD library) and transfer through Xbee (series 2) Due to limitation on xbee, have to break to 60 bytes and send until the complete file send. I think, the image stored in ASCII character.

 void setup() {

 Serial.begin(115200);

 if (!SD.begin()) {

Serial.println("begin failed");
return;
       }

 file = SD.open("PIC00.JPG");

 }
   void loop() {
   Serial.flush();

char buf[64];
if(file) {
while (file.position() < file.size())
         { 
   while (file.read(buf, sizeof(buf)) == sizeof(buf))  // read chunk of 64bytes 
         {

        Serial.write(buf); // Send to xbee via serial
         delay(50); 
         }

      }
       file.close();
} }

But this method, i can not see complete image transfer at Serial Write. After a while, i came to know the start of image is Y (ascii chracter) and U (end character). I can see only end start character Y can not see the proper end character.

Please advise...trying hard solve this issue. Big Thanks...

Upvotes: 0

Views: 2967

Answers (1)

tomlogic
tomlogic

Reputation: 11694

The JPEG is actually binary data. To send it, use the version of Serial.write() that includes a length parameter for the number of bytes to send. Otherwise, it thinks you're trying to send a null-terminated string.

(Declare bytesread as a byte at the top of your function.)

while ((bytesread = file.read(buf, sizeof(buf))) > 0)
{
    Serial.write(buf, bytesread); // Send to xbee via serial
    delay(50); 
}

Also note that the delay might not be sufficient -- you should really be using a serial port with hardware flow control (monitoring /CTS from the XBee module) so you know when it's clear to send data to it.

Upvotes: 1

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