Serial I/O functions with Servo

Question

So I've hooked up a Servo motor to digital pin 6 on my Arduino. I want to type a number into the Serial port, and have the Servo rotate to that degree.

I'm trying to make two functions,

1) asks and receives a number from a serial port between 10 & 170. asks for re-entry if invalid. only returns when the number is good.

2) takes in a degree argument, writes the argument as a servo degree, prints out the status: "Servo moved x ticks to y degrees."

#include <Servo.h>

Servo myServo;

int deg;
int degree;
int inputDeg;

int ang;
int angle;
int inputAng;

int servoMin = 10;
int servoMax = 175;

int recieveNum(int inputDeg) {
  inputDeg = Serial.parseInt();
  if (inputDeg >= 0 && inputDeg <= 180) {
     Serial.println("You did great!");
     return degree;
  } else {
     Serial.println("Hey! Try giving me a number between 0 and 180 this time.");
  }
 }

int servoTranslate(int inputAng) {
  angle = map(degree, 0, 180, servoMin, servoMax);
  return angle;
}

void setup() {
  Serial.begin(9600);
  myServo.attach(6);
}

void loop() {
  if (Serial.available() == 0) {}
  else {
    recieveNum(deg);

    int finalAng = servoTranslate(degree);

    Serial.print("  Servo moved ");
    Serial.print(degree);
    Serial.print(" tick(s) to ");
    Serial.print(finalAng);
    Serial.println("º");

    myServo.write(finalAng);
  }
}

I am still pretty new to c++, and I think it might just be a matter of variables being mixed up. Using pointers also seems to be an option but haven't gotten far trying to implement those.

In recieveNum() you need another return statement at the end of the function. Besides that it's completely unclear what you'r asking. — πάντα ῥεῖ

vcp vcp · Accepted Answer · 2016-03-07T07:15:59

This should work for you:

Function recieveNum should return -1 to indicator invalid input:

int recieveNum(int inputDeg) 
{
  inputDeg = Serial.parseInt();
  if (inputDeg >= 0 && inputDeg <= 180) {
    Serial.println("You did great!");
    return degree;
  } else {
    Serial.println("Hey! Try giving me a number between 0 and 180 this time.");
  }
  return -1; 
  ^^^^^^^^^
}

void loop() 
{
  if (Serial.available() != 0) 
  {
     if(-1 != recieveNum(deg))
     { // Valid 'deg'
       int finalAng = servoTranslate(degree);
       Serial.print("  Servo moved ");
       Serial.print(degree);
       Serial.print(" tick(s) to ");
       Serial.print(finalAng);
       Serial.println("º");
     }
  } 
  myServo.write(finalAng);
}

Serial I/O functions with Servo

1 Answers