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arduino count (simple C question)

e14 Contributor

Hi

another rookie question about coding with arduino

i simple need to make arduino to count from 0 to 180 with steps of 10 when it reach 180 I want that start to count from 180 to 0 and again again

I wrote this:

 

#include <Servo.h>

Servo myServo;

 

 

int const potPin = A0;

 

 

 

int angleForced=0;

void setup() {

  myServo.attach(9);

 

  Serial.begin(9600);

}

 

 

void loop() {

 

 

  Serial.print("angleFORCED: ");

  Serial.print(angleForced);

 

  if (angleForced < 179){

    angleForced=angleForced+10;

   

  } else if (angleForced >=179){

    angleForced=angleForced-10;

  }

 

  myServo.write(angleForced);

  delay(1000);

 

}

 

 

the problem in the code is:

when it reach 180 it count down to 170 and I get in to a loop of 180 170 180 numbers.

What I want is 0 10 20 30 ....to 180 170 160 ...to 0 etc etc

 

Cheers

D

Parents

  • Hi Dani

     

    You need a flag to show whether you are counting up or down.

     

    Here is a little sketch to illustrate a possible solution:

     

    /*

      demonstrate up down counter

      Neil Kenyon 01 February 2014

      Public domain

    */

    int count = 0;                   // counter value

    int upperLimit = 180;      // Upper limit

    int lowerLimit = 0;           // Lower limit

    boolean up = true;          // Counter direction flag

                                              // true says "countup"; false says "count down"

    void setup()

    {

      Serial.begin(9600);  

    }

     

    void loop()

    {

      Serial.println(count);

      Serial.println(up);                   // This will show 1 for true and 0 for false

     

      if (up ) {                                    // Only do this if we are counting up

        if (count < upperLimit ) {

          count = count + 10;

          if (count == upperLimit) {    // Reached upper limit

            up = false;                           // Set the flag false to count down

          }

        }

      }

      else if (count > lowerLimit) {

        count = count - 10;

        if (count == lowerLimit) {      // Reached lower limit

          up = true;                              // Set the flag false to count down

        }

      }

      delay(500); 

    }

     

    I hope this helps

     

    Best wishes

     

    Neil

  • in reply to neilk

    thanks so much

    ill try as soon as possible

     

    it makes so sense

     

    do you have a web side book that teach the very basic of arduino c programming language

     

    I feel that even if I follow the tutorial in the arduino starter kit book I don't have the right background in C to over come issue that I found when I want to do something different then the tutorial.

     

    cheeeeers

     

    D

  • in reply to e14 Contributor

    Dani

     

    I'm not a trained C programmer either. However, I have worked through ALL of Jeremy Blum's Tutorials, as well as lots of others you can find in the web.

     

    You'll soon pick it up.

     

    Neil

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