How do I split one string into two strings?

Projects Programming
1

I'm trying to create a transmitter with joysticks and a receiver with servos using Arduino Uno boards with XBee modules. How should the string being sent from the transmitter be formed? How do I split one string into two strings? How are strings sent using Serial.print terminated?

2

How should the string being sent from the transmitter be formed?

That depends on what you want to send, and how.

How do I split one string into two strings?

That would depend on how the string, if a string is even appropriate, is formed. Possibly using strtok().

How are strings sent using Serial.print terminated?

However you elect to terminate them. Nothing is appended to the string for you.

3

Multi servo test code delimited with a ,

//zoomkat 11-22-12 simple delimited ',' string parse 
//from serial port input (via serial monitor)
//and print result out serial port
//multi servos added 

String readString;
#include <Servo.h> 
Servo myservoa, myservob, myservoc, myservod;  // create servo object to control a servo 

void setup() {
  Serial.begin(9600);

  //myservoa.writeMicroseconds(1500); //set initial servo position if desired

  myservoa.attach(6);  //the pin for the servoa control
  myservob.attach(7);  //the pin for the servob control
  myservoc.attach(8);  //the pin for the servoc control
  myservod.attach(9);  //the pin for the servod control 
  Serial.println("multi-servo-delimit-test-dual-input-11-22-12"); // so I can keep track of what is loaded
}

void loop() {

  //expect single strings like 700a, or 1500c, or 2000d,
  //or like 30c, or 90a, or 180d,
  //or 30c,180b,70a,120d,

  if (Serial.available())  {
    char c = Serial.read();  //gets one byte from serial buffer
    if (c == ',') {
      if (readString.length() >1) {
        Serial.println(readString); //prints string to serial port out

        int n = readString.toInt();  //convert readString into a number

        // auto select appropriate value, copied from someone elses code.
        if(n >= 500)
        {
          Serial.print("writing Microseconds: ");
          Serial.println(n);
          if(readString.indexOf('a') >0) myservoa.writeMicroseconds(n);
          if(readString.indexOf('b') >0) myservob.writeMicroseconds(n);
          if(readString.indexOf('c') >0) myservoc.writeMicroseconds(n);
          if(readString.indexOf('d') >0) myservod.writeMicroseconds(n);
        }
        else
        {   
          Serial.print("writing Angle: ");
          Serial.println(n);
          if(readString.indexOf('a') >0) myservoa.write(n);
          if(readString.indexOf('b') >0) myservob.write(n);
          if(readString.indexOf('c') >0) myservoc.write(n);
          if(readString.indexOf('d') >0) myservod.write(n);
        }
         readString=""; //clears variable for new input
      }
    }  
    else {     
      readString += c; //makes the string readString
    }
  }
}
4

Zoomkat's code almost works but I think it needs a slight delay in the loop. Where should I put the delay(x) command where x is a number?

5

Where should I put the delay(x) command where x is a number?

You shouldn't. You should explain why you think it needs a delay.

6

The servos run "on their own". They may be getting "garbage" values. The Serial Monitor shows "garbage" values.

7

The servos run "on their own".

No "they" don't. They "run where" you send "them"

They may be getting "garbage" values.

From "where"?

The Serial Monitor shows "garbage" values.

"Which you" are not going "to show us". Fine.

Do the useless quotes help?

8

I think the OP may have missed the idea that he may be sending data faster than it can be received and processed.