Arduino Serial RC control

Projects General Guidance
1

Hy,

i have Windows Form application which reads PlayStation 3 controller and sends data of speed and direction to Arduino via Serial interface.
I'm having troubles with serial communication. Received integers are not correct. Could you Pros inspect the code and suggest better method of doing this? Thanks :wink:

  1. Arduino sends "OK" to PC. (Arduino is ready to receive data...)
  2. PC reads serial data
    -----if "OK" is received, respond with current GamePad values.
    -----Serial.WriteLine(1,255,2,180); (1=speed, 255=motor speed, 2=direction, 180=servo position)
  3. Arduino reads this values and use it in switch sentenc.
#include <Servo.h> 

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 34, 35, 36, 37);

int data = 0;   // for incoming serial data
Servo ServoDirection;  //servo for direction control

//PINS
const int ForwardBackward = 40;
const int Motor = 2;
const int ServoMotor = 9;
const int LED = 13;

void setup() {
  Serial.begin(19200);
  pinMode(ForwardBackward, OUTPUT);
  pinMode(Motor, OUTPUT);
  ServoDirection.attach(ServoMotor);
  lcd.begin(16, 2);
  pinMode(LED, OUTPUT);
}

void loop() {
  ClearSerial();  //removes any data in serial recive buffer
  lcd.setCursor(0, 0);  lcd.print("  ");
  //Signal PC software that I am redy!
  Serial.println("OK");
  Serial.flush();  //wait until serial data is send.
  lcd.setCursor(0, 0);  lcd.print("OK");
  // send data only when you receive data:
  if (Serial.available() > 0) {
    // read the incoming integer:
    data = Serial.parseInt();
    lcd.setCursor(3, 0);  lcd.print(data);
    //start appropiant function
    WhatToDo(data);
  }
}

void WhatToDo(int data) {
  switch (data) {
    case 1:
      //Speed control
      Speed();
      break;
    case 2:
      //Direction control
      Direction();
      break;
    case 3:
      //LED light
      Light();
      break;
  }
}

void Speed() {
  //Request speed data
  data = Serial.parseInt();
  lcd.setCursor(0, 1);  lcd.print(data);
  //Set forward or backward movement
  if(data < 0) {
    digitalWrite(ForwardBackward, LOW);
    data *= -1;  //Only positiv numbers for PWM
  } else {
    digitalWrite(ForwardBackward, HIGH);
  }
  //Set speed of Motor
  analogWrite(Motor, data);
}

void Direction() {
  //Request direction data (0-180)
  data = Serial.parseInt();
  lcd.setCursor(0, 1);  lcd.print(data);
  //Set servo position
  ServoDirection.write(data);
}

void Light() {
  //Request LED status
  data = Serial.parseInt();
  lcd.setCursor(0, 1);  lcd.print(data);
  //Switch Led on/off
  if(data == 1)
    digitalWrite(LED, HIGH);
  else if (data == 0)
    digitalWrite(LED, LOW);
}

void ClearSerial() {
  while (Serial.read() > 0) {}
}
2 
  ClearSerial();  //removes any data in serial recive buffer

Why do you want to throw away random amounts of unread data? If it isn't important, quit sending it. If it is, quit deleting it.

  Serial.println("OK");
  Serial.flush();  //wait until serial data is send.
  lcd.setCursor(0, 0);  lcd.print("OK");

By the time you get done diddling with the LCD, the "OK" would have been shifted out. What is the reason for blocking until the O has been sent?

Received integers are not correct.

You send something. Something gets received. You've told us nothing about either one, yet you want us to tell you what is wrong. I don't think it works that way.

Could you Pros inspect the code and suggest better method of doing this?

Sure. Ditch the calls to parseInt() until you know EXACTLY what you are receiving and EXACTLY what the parseInt() method is doing.

3

Arduino sends "OK\r" to PC.
PC responses with "1,255,2,90,".

Then Arduino parses first integer from serial buffer.
This integer goes to switch function.
From there, appropiant method is called witch parses next available integer from buffer to be used for motor speed or servo control.

Iv updated my loop code to this:

void loop() {
  Serial.println("OK");						//Signal PC software that I am redy!

  while (Serial.available() > 0) {			        //send data only when you receive data:
    data = Serial.parseInt();					//read the incoming integer:
    WhatToDo(data);						//start appropiant function
  }
}

The remaining part of the code is unchanged. Arduino is still getting strange numbers.

4

Arduino is still getting strange numbers.

That's a real shame.

Now, if you tell us what you get, we may be able to help.

5

Ok i got it to work but there is another problem.
When PC and Arduino are connected over USB cabel, serial communication works.

When i switch to Wireles serial communication (APC220) it works only in one direction Arduino to PC. The Arduino doesent receive any characters.

What could be a logical explanation for this?
(I am reading characters from serial and printing them to LCD. I receive chars over USB but not over APC220)

6

dgibum:
What could be a logical explanation for this?

Your system has a design fault, or a hardware fault, or a software fault.