Arduino - LED Bar Graph

Sohail Gulam

unoarduino

This example shows you how to read an analog input at analog pin 0, convert the values from analogRead() into voltage, and print it out to the serial monitor of the Arduino Software (IDE).

// these constants won't change:
const int analogPin = A0; // the pin that the potentiometer is attached to
const int ledCount = 8; // the number of LEDs in the bar graph
int ledPins[] = {2, 3, 4, 5, 6, 7, 8, 9}; // an array of pin numbers to which LEDs are attached
void setup() {
   // loop over the pin array and set them all to output:
   for (int thisLed = 0; thisLed < ledCount; thisLed++) {
      pinMode(ledPins[thisLed], OUTPUT);
   }
}
void loop() {
   // read the potentiometer:
   int sensorReading = analogRead(analogPin);
   // map the result to a range from 0 to the number of LEDs:
   int ledLevel = map(sensorReading, 0, 1023, 0, ledCount);
   // loop over the LED array:
   for (int thisLed = 0; thisLed < ledCount; thisLed++) {
      // if the array element's index is less than ledLevel,
      // turn the pin for this element on:
      if (thisLed < ledLevel) {
         digitalWrite(ledPins[thisLed], HIGH);
      }else { // turn off all pins higher than the ledLevel:
         digitalWrite(ledPins[thisLed], LOW);
      }
   }
}