Arduino Uno to Arduino Uno Word.doc file transfer

Question

I have written a 2 sets of code for the transmitter and receiver section. I am trying to send a word document file from 1 arduino uno to the next arduino uno through serial TX and RX. The file is initially loaded into a micro sd card module at the transmitter section. I would like to transfer that file to the receiver section's sd card module. I am able to receive an empty word document at the receiver section. There is no information in the document. I would like some help with this. I will attach the transmitter and receiver code below.

Transmitter code:

#include <SD.h>
#include <SPI.h>
File fileIn;
void setup() {
 // put your setup code here, to run once:
 Serial.begin(9600);
 while (!Serial){
 ; // wait for serial port to connect. Needed for native USB port only
 }
 Serial.print("Initializing SD card...");
 if(!SD.begin(4)){
 Serial.println(F("Initialization failed!"));
 return;
 } 
 Serial.println("Initialization done.");
 if(!SD.exists("student.txt")){
 fileIn = SD.open("student.txt", FILE_WRITE);
 fileIn.println(F("abc.txt"));
 }
 fileIn = SD.open("student.txt", FILE_READ);
 while(fileIn.available()){
 Serial.write(fileIn);
 }
 delay(1000);
 fileIn.close();
}
void loop() {
 // put your main code here, to run repeatedly:
}

Receiver code:

#include <SD.h>
#include <SPI.h>
File fileOut;
void setup() {
 // put your setup code here, to run once:
 Serial.begin(9600);
 while (!Serial){
 ; // wait for serial port to connect. Needed for native USB port only
 }
 Serial.print("Initializing SD card...");
 if(!SD.begin(4)){
 Serial.println(F("Initialization failed!"));
 return;
 }
 Serial.println("Initialization done.");
 if(SD.exists("student2.txt")){
 SD.remove("student2.txt");
 }
 fileOut = SD.open("student2.txt", FILE_WRITE);
 while(fileOut.available()){
 Serial.write(fileOut); 
 }
 delay(1000);
 fileOut.close();
 Serial.println("It worked!");
}
void loop() {
 // put your main code here, to run repeatedly:
}

Answer 1

 while(fileOut.available()){
 Serial.write(fileOut); 
 }

This doesn't quite do what you think it does.

Instead you should send the file length first and then do:

for(unsigned long size = 0; i< fileLength; i++){
 Serial.write(fileOut.read()); 
}

You should also investigate some kind of rate limiting to avoid overwhelming the reciever and having to drop some bytes.

• Hari Tharan: Is it possible to read the line and take that as a file length in the 1st arduino and how would I implement this with the receiver arduino?
• ratchet freak: File has a size() member function. And just send 4 bytes with the length before you send the rest of the file. on the recieve side the first 4 bytes read will be the size of the file you will be recieving.