Knob modified program doesn't work :C

Using Arduino Programming Questions
1

Hello everyone!
I'm a new Arduino developer, so I'm trying to make the examples and understand what their code means to do!
Anyway, I tried to modify the Knob example (it uses a potentiometer to turn a micro servo) getting this final code:

#include <Servo.h> 
 
Servo myservo;  // create servo object to control a servo 
 
int potpin = 0;  // analog pin used to connect the potentiometer
int val;    // variable to read the value from the analog pin 

int led1 = 9;
int led2 = 10;
int led3 = 11;
int led4 = 6;
int led5 = 7;

int n = 180;   // value to search
 
void setup() 
{ 
  myservo.attach(8);  // attaches the servo on pin 9 to the servo object 
  pinMode(led1, OUTPUT);  // Too High LED (red)
  pinMode(led2, OUTPUT);  // Near - High LED (yellow)
  pinMode(led3, OUTPUT);  // Right Position LED (green)
  pinMode(led4, OUTPUT);  // Near - Low LED (yellow)
  pinMode(led5, OUTPUT);  // Too Low LED (red)
} 
 
void loop() 
{ 
  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023) 
  val = map(val, 0, 1023, 0, 180);     // scale it to use it with the servo (value between 0 and 180) 
  myservo.write(val);                  // sets the servo position according to the scaled value 
  delay(15);                           // waits for the servo to get there 
  if (val < (n-5)) {                   // this If cicle finds what LED to light
    digitalWrite(led5, HIGH);          // the LEDs are inverted because of the positive and negative rotation are inverted on my servo
  }else{
    if ((val >= (n-5)) && (val < n)) {
      digitalWrite(led4, HIGH);
    }else{
      if (val = n) {
        digitalWrite(led3, HIGH);
      }else{
        if ((val > n) && (val <= (n+5))) {
          digitalWrite(led2, HIGH);
        }else{
          digitalWrite(led1, HIGH);
        }
      }
    }
  }
  digitalWrite(led1, LOW);             // turns off all the LEDs
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);
  digitalWrite(led5, LOW);
}

(code tags fixed by moderator: code, and /code

It's pretty easy, you set a number that you want to find as a corner measured in degrees and then you find it turning the potentiometer. The 5 LEDs help you finding the right position by saying you if the corner is bigger than the one you want to find, or near big etc (there are comments in the code, you can see all there), just as a guitar tuner would do.
Anyway, for some reason the LEDs n° 1 and 2 (Digital input n° 9 and 10) don't light up. They are all connected right, everyone the same as the others.

Basically it's just [digital n] - [220 Ohm resistor] - [LED's anode] - [LED's cathode] - [gnd]

Any explanations on why this simple thing doesn't work?

Thanks everyone! :D[/code]

2

Maybe because you turn them off almost immediately after turning them on?

          digitalWrite(led2, HIGH);
        }else{
          digitalWrite(led1, HIGH);
        }
      }
    }
  }
  digitalWrite(led1, LOW);             // turns off all the LEDs
  digitalWrite(led2, LOW);

Where the others have a chance to be on a little longer and be visible before they are turned off.
Or, the logic is not quite correct.

3

Like this:

if (val = n) {

needs == for a comparison,
vs = for an assignment. Common mistake.

4

CrossRoads:
Like this:

if (val = n) {

needs == for a comparison,
vs = for an assignment. Common mistake.

Yeah, now I see this mistake but I don't know why it works with only 1 "=" too!
Anyway it's strange because only the "higher corner" LEDs doesn't light!

Actually now it works, I put a delay(50) before the LOW lines, so now it's alright (the LEDs are even brighter too!)

Thank you! :smiley:

5

Your knob input can only go up to 180. When you set n=180 you are assured that you will never go over n. The lights that tell you how far past 'n' you have gone won't be used.