Project tutorial
Bar Graph

Bar Graph © CC BY-NC-ND

Ten LEDs connected to an Arduino Uno and a potentiometer.

  • 22,580 views
  • 24 comments
  • 63 respects

Components and supplies

Apps and online services

About this project

There are ten LEDs connected to an Arduino Uno and a potentimeter. When you rotate the potentiometer, the LEDs will be lit one by one.

Code

GraphC/C++
const int analogPin = A0;   // the pin that the potentiometer is attached to
const int ledCount = 10;    // the number of LEDs in the bar graph

int ledPins[] = {
  2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};   // 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);
    }
    // turn off all pins higher than the ledLevel:
    else {
      digitalWrite(ledPins[thisLed], LOW);
    }
  }
}

Schematics

Bar Graph
Bargraph bb mfhm8kyoal

Comments

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