Project tutorial

Bar Graph © CC BY-NC-ND

Ten LEDs connected to an Arduino Uno and a potentiometer.

  • 5,653 views
  • 15 comments
  • 34 respects

Components and supplies

Apps and online services

About this project

Hello! My name is Matei. I'm eleven years old and this is my third 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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