Fading LED, for() loop with potentiometer

Projects General Guidance
1

I am very new to Arduino but I am learning all the time. (at this point, 4 days)
I took a look at the already put together programs in the programming environment,
then chose the one with Pulse Width Modulation for fading an LED. (it is in OPEN, BASICS, FADE.)
I wanted to make it my own so I made an adjustment where in the for() loop, the test/condition is determined by the analog input of a potentiometer .

my code looks like this :

const int ledPin = 9;    // LED connected to digital pin 9-
const int pot = A0;

void setup()  { 
pinMode( ledPin,OUTPUT);
  pinMode (pot,INPUT);
Serial.begin(9600);
} 

void loop()  { 
 
int value = analogRead(pot);
  

  // fade in from min to max in increments of 5 points:
  for(int fadeValue = 0 ; fadeValue <= value; fadeValue += 5) { 
    // sets the value (range from 0 to 255):
    analogWrite(ledPin, fadeValue);         
    // wait for 30 milliseconds to see the dimming effect    
    delay(30);                            
  } 

  // fade out from max to min in increments of 5 points:
  for(int fadeValue = value ; fadeValue >= 0; fadeValue -= 5) { 
    // sets the value (range from 0 to 255):
    analogWrite(ledPin, fadeValue);         
    // wait for 30 milliseconds to see the dimming effect    
    delay(30);                            
  } 
  Serial.println(value);
  delay(1000);
}

It works, to a degree..

The problems are that the serial port will not print anything. The communications and also, instead of fading on and off, it goes something like this :

fade from 0 to high 3 times one right after another , then fade from high to 0 three times, and repeat,
instead of fading from off to on and back again.

here are some pictures of wiring.

I will keep working, If you can find whats wrong or give advice, THANK YOU.

1228141412[1].jpg

1228141412b[1].jpg

2

Im sorry, in problems, that is supposed to say that the communications light was not even on instead of (the comminications)

3

Hi EskymoCho

Don't think you need this for analog input.

pinMode (pot,INPUT);

This will give a value between 0 and 1023. You need to scale the value to 0 to 255 for the analogWrite.

int value = analogRead(pot);

Try this:

int value = analogRead(pot) / 4;

the serial port will not print anything

Do you have the speed in serial monitor set to 9600, to match the speed set in your program?

Regards

Ray

4

I like to use the map() function whilst reading analog values. Then I can set min/max within useful range. In your case 0-255. You may also want to look into the constrain() function.

5

thanks guy so much. It works now! hackscribble's comment helped.

6

hey knystol, I looked on this site'spage about map at map() - Arduino Reference this says that all the analog values over 255will be omitted. Hackscribble's way works by using a proportion instead. if there is something I am missing please let me know.

7

Map will take a range let's say from 0-1023 and map it to let's say 0-255.

You can have a pot that should map let's say 4 different levels, then use map() and map from 0-1023 (analog read will always give you this initial range, at least on the Uno), then map from 1-4, this is how great the map()-function is!