LED Blinking Speed using Potentiometer Arduino Uno

Other Hardware LEDs and Multiplexing
1

Hello, I am trying to control the blink speed of an arduino uno using a potentiometer. I am basing this off of a previous topic (Using Potentiometer to Control LED Blink Speed - Exhibition - Arduino Forum). Here is the code that I have been using thus far, ignore the LCD screen stuff, it works.

#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,2,1,0,4,5,6,7);
int potpin = A2;  
int ledpin = 13;
int val;    
int lastChange;// the time of changing pin state

void setup()
{
  pinMode(ledpin, OUTPUT);
  val = map(analogRead(potpin), 0, 1023, 500, 5); 
  
  lcd.setBacklightPin(3,POSITIVE);
  lcd.setBacklight(HIGH);
  lcd.begin(16, 2);
  lcd.setCursor(0,0);
  Serial.begin(9600);
  lcd.print("RPM = ");
  lcd.setCursor(0,1);
  lcd.print("Temp (F) = ");
  lcd.setCursor(20,0);
  lcd.print("Bearing Life = ");
}

void loop()
{
 lastChange = millis();
 digitalWrite(ledpin, HIGH);
 while(lastChange + val <= millis())  // loop while there's time for it :)
 {
   val = map(analogRead(potpin), 0, 1023, 500, 5);  // read the value every time
   Serial.println(val);
 }

 // the same here:
 digitalWrite(ledpin, LOW);
 lastChange = millis();
 while(lastChange + val <= millis())
 {
   val = map(analogRead(potpin), 0, 1023, 500, 5); 
   Serial.println(val); 
 }
}

The potentiometer is not changing the speed and I'm not sure what the issue is. I am having trouble including some images of the way it is connected, due to file size restrictions, so please let me know if those would be helpful. Thank you.

2

Serial.println is blocking as long as buffer is full. Remove it and see if it helps.

EDIT: as written it will blink much much faster than you can see. It will be more like dimming the LED.

EDIT2: after rereading it is not so bad: the LED should blink from 1Hz to 100Hz. Since blinking can be seen to ~40Hz (IIRC) you should be able to see the blinking when it is slow. What values you see on Serial.println? What the LED does?

3

predzZzZzZ:

int val;    

int lastChange;// the time of changing pin state

These variables should be 'unsigned long' to hold a millis() value
and use:

while(millis() - lastChange < val) {

Also... I presume you are seeing 'val' change in the serial monitor ?

Yours,
TonyWilk