Led and potentiometer

Other Hardware LEDs and Multiplexing
1

Hi,

I'm a beginner with an Arduino Uno and have a question about Led and potentiometer.

I have the really simple following code :

int Pot = A0;
int Led = A1;
int Val;
int Niv;

void  setup(){
 Serial.begin(9600);
 pinMode(Led,OUTPUT);
 digitalWrite(Led,LOW);
}

void loop(){
  Val = analogRead(Pot);
  Niv = Val / 4;
  Serial.println(Niv);
  analogWrite(Led,Niv);
  delay(50);
}

My potentiometer gives information through A0, and my red led is controlled through A1.
When I trace my "Niv" variable, i get a correct value between 0 and 255.
My problem is I don't understand why my red led is only lightening from 128 to 255 with no change in brightness... and stays off from 0 to 128 !

Any information for me ?
Thanks !

2

My problem is I don't understand why my red led is only lightening from 128 to 255 with no change in brightness.

Because the pin you have connected to is not capable of PWM, it is not an analogue output.
On the Arduino PWM enabled pins are marked with a ~ on a UNO these are pins 11, 10, 9, 6, 5 & 3. Use one of those pins.

3

Arf, so simple, thank you !

4

Hi!
Here is a bit harder example, but its working. All u need are 3 LEDs on pins 42, 52 and 30, potentiometer, of course arduino and few wires.
Have fun!

void setup() {
  
  pinMode(42, OUTPUT);    //defining pins
  pinMode(52, OUTPUT);    //defining pins
  pinMode(30, OUTPUT);    //defining pins
  
  Serial.begin(9600);
}


void loop() {
 
  int sensorValue = analogRead(A0);  //reading from potentiometer

  float voltage = sensorValue * (5.0 / 1023.0);  //defining sensor value

  Serial.println(voltage);    //printing voltage in Serial monitor
  
  
//now how LEDs are turning on
  
  if (voltage<1) digitalWrite(52, HIGH);


  if (voltage>1) digitalWrite(52, LOW);


  if (voltage<1) digitalWrite(42, LOW);


  if (voltage>1, voltage<4) digitalWrite(42, HIGH);
  
  
  if (voltage>4) digitalWrite(42, LOW);
  
  
  if (voltage>4) digitalWrite(30, HIGH);
  
  if (voltage<4) digitalWrite(30, LOW);
  
  if (voltage<1) digitalWrite(42, LOW);
  
}