Servo Operation Issues

Using Arduino Programming Questions
#1

I am encountering a weird error. My program is meant to rotate my servo to 90 degrees when I flick a switch one way, and rotate back up when I flick it the other way. I am doing this by running the arduino’s 5 volts through the switch and into the 7th digital pin. When I turn it off, it waits around 8 seconds and then turns and it also grinds the gears. It rotates back when I flip the switch back. I am using a Generic (Sub-Micro) Servo from SparkFun.
Here is my code:

#include<Servo.h>
Servo my_servo;
int servo_state = 0;
int pos = 0;
void setup()
{
  my_servo.attach(12);
  pinMode(7,INPUT);
  my_servo.write(0);
  Serial.begin(9600);
}


void loop()
{
  
  if (digitalRead(7) == HIGH && servo_state == 0)
  {
    my_servo.write(90);
    delay(5);
    servo_state = 1;
  }
  if (digitalRead(7) == LOW && servo_state == 1)
  {
    my_servo.write(0);
    delay(5);
    servo_state = 0;
  }
  if (digitalRead(7) == HIGH)
  {
    Serial.print('high');
  }
  if (digitalRead(7) == LOW)
  {
    Serial.print('low');
  }
}

Is there anything in there that would be causing the servo delay? Or is this something to do with the hardware?

#2

Or is this something to do with the hardware?

No. The problem is a floating pin. Wire your switch correctly to prevent it. One leg to the digital pin and one leg to ground, and turn on the internal pullup resistor (INPUT_PULLUP).

    Serial.print('high');

Would you post a picture of your keyboard, with the ONE key that you pressed to get the ONE character in single quotes there?

#3

@PaulIS

So rather than having

pinMode(7,INPUT);

It is supposed to be like this?

pinMode(7,INPUT_PULLUP)

Also, what ONE character are you referring to?

#4

What he is trying to say is that single quotes are for single characters. Double quotes for strings.

And you need to do more than just change the INPUT to INPUT_PULLUP. You also need to wire the switch so it is between the digital pin and ground so that a made switch reads LOW and an unmade switch reads HIGH.

#5

Also, I think you need to allow more time for the servo to move to its new position. You seem only to be allowing 5 millisecs.

You should also consider reorganizing your code so there is only a single digitalRead(7) in loop().

Have a look at planning and implementing a program

…R

#6

Two simple servo button setups.

//zoomkat servo button test 7-30-2011
//Powering a servo from the arduino usually *DOES NOT WORK*.

#include <Servo.h>
int button1 = 4; //button pin, connect to ground to move servo
int press1 = 0;
Servo servo1;

void setup()
{
  pinMode(button1, INPUT);
  servo1.attach(7);
  digitalWrite(4, HIGH); //enable pullups to make pin high
}

void loop()
{
  press1 = digitalRead(button1);
  if (press1 == LOW)
  {
    servo1.write(160);
  }
  else {
    servo1.write(20);
  }
}

//zoomkat servo button test 7-30-2011

#include <Servo.h>
int button1 = 4; //button pin, connect to ground to move servo
int press1 = 0;
Servo servo1;

void setup()
{
  pinMode(button1, INPUT);
  servo1.attach(7);
  digitalWrite(4, HIGH); //enable pullups to make pin high
}

void loop()
{
  press1 = digitalRead(button1);
  if (press1 == LOW)
  {
    servo1.write(160);
    delay(2000);
    servo1.write(20);
  }
}
#7