LED Bar Graph

The bar graph – a series of LEDs in a line, such as you see on an audio display – is a common hardware display for analog sensors. It’s made up of a series of LEDs in a row, an analog input like a potentiometer, and a little code in between. You can buy multi-LED bar graph displays fairly cheaply,


LED Bar Graph Pinout


Pin No.

Pin Name


1 to 10


All are anode pins of the respected LED

11 to 20


All are cathode pins of the respected LED



  • 10 LEDs with individual control
  • High Luster
  • High Intensity
  • Economically Priced
  • Breadboard or Perf board friendly
  • RoHS Compliant
  • Wide viewing angle


Technical Specifications:

  • Forward Current: 20mA
  • Forward Voltage: 2.0V to 2.2V (maximum)
  • Luminous Intensity: 60mcd
  • Wavelength: 630nm
  • Operating Temperature: -25℃ to 85℃
  • Storage Temperature: -30℃ to 85℃
  • Soldering Temperature: 260℃ for 5sec.
  • Available Colors: Red, Green, Blue, Yellow, Orange, Amber


Where LED Bar Graphs are Used?

LED Bar Graph is an LED array, which is used to connect with electronic circuit or microcontroller. It’s easy to connect LED bar graph with the circuit like as connecting 10 individual LEDs with 10 output pins. Generally we can use the LED bar graph as a Battery level Indicator, Audio equipments, and Industrial Control panels. There are many other applications of LED bar graphs.


How to Use LED Bar Graph?

You can control the LED bar graph with the microcontroller or connecting to an electronic circuit.

First, we will show you that how to connect a LED Bar Graph with the Micro-controller. When connecting to the Micro-controller you just have to connect the Anode pins of the LED Bar graph and ground the Cathode pins using a resistor in between as shown in the image below. Then Upload your code and drive the LED Bar Graph accordingly.

Now, if you want to use a LED Bar graph in a Circuit then you can connect the Bar with the LM3914 Dot/Bar Display Driver. LM3914 is used to drive these LED Bar Graph displays. A circuit diagram given below will help you to understand the connection.




Interfacing with Arduino:



  LED bar graph


  Turns on a series of LEDs based on the value of an analog sensor.

  This is a simple way to make a bar graph display. Though this graph uses 10

  LEDs, you can use any number by changing the LED count and the pins in the



  This method can be used to control any series of digital outputs that depends

  on an analog input.


  The circuit:

  – LEDs from pins 2 through 11 to ground


  created 4 Sep 2010

  by Tom Igoe


  This example code is in the public domain.





// these constants won’t change:

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);





  • Industrial Controls
  • Instrumentation
  • Office Equipment
  • Computer Peripherals
  • Consumer Products
  • Moving Message Display
  • Digital Display
  • Score Boards