Receiver xbee receiving data even if the Transmitter is not sending?

Question

TX code:

#include <SoftwareSerial.h>

const int MAX_LENGTH = 2;
char buffer[MAX_LENGTH];
char lineFeed = 2;

SoftwareSerial   Xbee(10, 11);

void setup() {
  Serial.begin(9600);
  Xbee.begin(9600);
}

void loop() {
  int length = Serial.readBytesUntil(lineFeed, buffer, MAX_LENGTH);
  int i = 0;
  while( i < length )
  { 
    Serial.print(buffer[i]-48); 
    Xbee.print(buffer[i]-48);  
    i++;
  }        
}

RX code:

const int MAX_LENGTH = 2;
char buffer[MAX_LENGTH];
char lineFeed = 2;

void setup() {
  Serial.begin(9600);
}

void loop() {
  int length = Serial.readBytesUntil(lineFeed, buffer, MAX_LENGTH);
  int i = 0;

  while( i < length )
  { 
    Serial.print(buffer[i]-48);
    i++;
  } 
}

NOTE :

1- The Rx xbee is receiving data even if am not sending and even if the TX xbee is powered off

2- When i send data from the TX xbee id didn't get revived by the RX xbee

I need to solve both problems.

*** What i need exactly is to send serial data from my pc to arduino and send it wireless through xbee and then receive to the other arduino connected to my circuit

Answer 1

The reason that it is printing characters with no input is that the readBytesUntil function has a timeout. If no new characters are received for a certain amount of time, "Serail.setTimeout()" seconds, it will just continue with the code. the default timeout is 1 second.

The reason you are not receiving what you transmit (or at least a reason) is that the RX code does not read from an xbee, but reads from regular "serial".

I recommend you try something simple first to test the xbee's configuration, like having TX run this:

void loop(){
    xbee.println("Hello");
    delay(1000);
}

and RX run something to echo serial like this:

 void loop(){
     if(xbee.available()){
         Serial.print((char)xbee.read());
     }
}

And make sure you set up an xbee object an the receiving side first.