Setting up software serial

Projects Programming
1

Hi. I am trying to use two XBee S1 and two Arduino Uno to control a servo motor (continuous rotation) wireless with a joystick. I already got everything working if I do everything in one arduino, so the joystick code and the code to write the value to the servo work perfectly. The problem is when I connect my servo with the XBee shield, the servo is always rotating in one direction at full speed. I have been told it has something to do with the serial connection the XBees use. I was told to use Software Serial to change my RX and TX pins. I changed XB_TX to 6 and XB_RX to 7 on both Shields. However, I don't see anything on the serial monitor when I try this.

This is my code for the reciever:

#include <Servo.h>
#include <SoftwareSerial.h>

SoftwareSerial XBee(6, 7); // RX, TX

const int servo1 = 9;       // first servo

int servoVal;           // variable to read the value from the analog pin

Servo myservo1;  // create servo object to control a servo

void setup() {

  //Servo  
  myservo1.attach(servo1);  // attaches the servo


  // Inizialize Serial
  XBee.begin(9600);
  Serial.begin(9600);
}


void loop() {
  // put your main code here, to run repeatedly:
   if (Serial.available())
  { // If data comes in from serial monitor, send it out to XBee
    XBee.write(Serial.read());
  }
  if (XBee.available())
  { // If data comes in from XBee, send it out to serial monitor
    Serial.write(XBee.read());
  }
    if (Serial.available() > 0) {
    servoVal = Serial.read();
    Serial.write(servoVal);
    myservo1.write(servoVal);
    //while(Serial.available()>0) Serial.read(); //flush?
    }
}

And, this is my code for the transmitter:

//#include <Servo.h>
#include <SoftwareSerial.h>
//// XBee's DOUT (TX) is connected to pin 2 (Arduino's Software RX)
//// XBee's DIN (RX) is connected to pin 3 (Arduino's Software TX)
SoftwareSerial XBee(6, 7); // RX, TX

const int joyV = 0;        // U/D Parallax Thumbstick

int servoVal;           // variable to read the value from the analog pin

void setup() {

  // Inizialize Serial
  XBee.begin(9600);
  Serial.begin(9600);
}


void loop(){

     if (Serial.available())
      { // If data comes in from serial monitor, send it out to XBee
        XBee.write(Serial.read());
      }
      if (XBee.available())
      { // If data comes in from XBee, send it out to serial monitor
        Serial.write(XBee.read());
      }


    servoVal = analogRead(joyV);           
    servoVal = map(servoVal, 0, 1023, 73, 120);     // scale it to use it with the servo (result between 70 and 180)
    Serial.println(servoVal);

}
2

In your receiver code you check whether data is available from the Xbee serial interface and if so you write it to the Serial interface, but you get the servoVal from the Serial interface. Why ?

You should be reading the servo value from the Xbee interface.

There is a similar problem with the transmitter code.
Read the pot value and send it via the Xbee interface.

3

Thank you. OK, so I fixed that. Now I am getting data on the receiver. But I still have the same problem. When I connect my servo, it just goes in one direction the whole time and doesn't respond to my pot values.

4

ivan787:
Thank you. OK, so I fixed that. Now I am getting data on the receiver. But I still have the same problem. When I connect my servo, it just goes in one direction the whole time and doesn't respond to my pot values.

So post the revised code.