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I'm new to Arduino and I'm following this tutorial: https://www.youtube.com/watch?v=T2HMJiy9b_I but the problem is the servo just keeps moving back and forwards on it own and the button is doing nothing when pressed please help.

Code:

#include <Servo.h>

Servo myservo;  // create servo object to control a servo
#define servoPin 3 //~
#define pushButtonPin 2 

int angle =90;    // initial angle  for servo
int angleStep =5;
const int minAngle = 50;
const int maxAngle = 110;

int buttonPushed =0;

void setup() {
  // Servo button demo by Robojax.com
  Serial.begin(9600);          //  setup serial
  myservo.attach(servoPin);  // attaches the servo on pin 3 to the servo object
  pinMode(pushButtonPin,INPUT_PULLUP);
   Serial.println("Robojax Servo Button ");
}

void loop() {
  if(digitalRead(pushButtonPin) == LOW){
    buttonPushed = 1;
  }
   if( buttonPushed ){
  // change the angle for next time through the loop:
  angle = angle + angleStep;

    // reverse the direction of the moving at the ends of the angle:
    if (angle <= minAngle || angle >= maxAngle) {
      angleStep = -angleStep;
       buttonPushed = 0;
    }
    myservo.write(angle); // move the servo to desired angle
      Serial.print("Moved to: ");
      Serial.print(angle);   // print the angle
      Serial.println(" degree");    
  delay(100); // waits for the servo to get there
   }


}
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  • I posted the code:robojax.com/learn/arduino/…. I need help with the code so when the button is pressed the servo will rotate 0 to 180 degrees and stop but the button is unresponsive and the servo just keeps moving back and forth Apr 26 '20 at 19:31
  • Edit your question. Select all of the code, and tap the {} code formatting button. Your code is unreadable as posted.
    – Duncan C
    Apr 26 '20 at 19:33
  • ok how about now Apr 26 '20 at 19:37
  • Once you push the button once and buttonPushed becomes 1 the servo will move forever because nothing ever sets buttonPushed back to 0. You need an else there to set it back to 0.
    – Delta_G
    Apr 26 '20 at 19:39
  • sorry, but I don't really know how to do that. :( Apr 26 '20 at 19:45
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This condition below is never met because a boolean comparison is implied :

if( buttonPushed ){

and buttonPushed is declared as :

int buttonPushed =0;

A proper comparison should be OK :

if( buttonPushed == 1) 
{ 
   // Do something
}

Also the buttons need proper debouncing or the push event will have undetectable results :

https://dduino.blogspot.com/2012/03/arduino-button-debouncing.html

enter image description here

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  • 1
    C++ will treat any non-zero value as true and 0 as false. It is perfectly legal to use an int inside an if statement in this way. If you would like I can post demonstration code to prove it. It not great coding style, but it won't cause any failure.
    – Delta_G
    May 1 '20 at 19:38
  • An if statement works with integers!
    – Sim Son
    May 1 '20 at 19:46
  • Mea culpa you are right : arduino.cc/reference/en/language/variables/constants/constants
    – skourkos
    May 1 '20 at 20:19

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