Note

Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

Why Join?

• Expert Support: Solve post-sale issues and technical challenges with help from our community and team.

• Learn & Share: Exchange tips and tutorials to enhance your skills.

• Exclusive Previews: Get early access to new product announcements and sneak peeks.

• Special Discounts: Enjoy exclusive discounts on our newest products.

• Festive Promotions and Giveaways: Take part in giveaways and holiday promotions.

ðŸ‘‰ Ready to explore and create with us? Click [here] and join today!

# 2.4 LED Bar GraphÂ¶

## OverviewÂ¶

In this lesson, you will learn something about LED Bar Graph. Generally, LED Bar Graph works as a battery level indicator, Audio equipment, industrial control panel. If we want, we can also find its other application.

## Fritzing CircuitÂ¶

In this example, we use digital pins 2~11 to drive the LED Bar Graph. LED Bar Graph has ten separate LEDs inside and each LED has two pins. The left pins 1~10 of LED Bar Graph are connected with the digital pins 2~11 respectively; the right side pins 11~20 are separately extended to same side of these 220ohm resistors whose other sides are identically connected to GND.

## CodeÂ¶

Note

• You can open the file `2.4_ledBarGraph.ino` under the path of `sunfounder_vincent_kit_for_arduino\code\2.4_ledBarGraph` directly.

• Or copy this code into Arduino IDE.

Uploaded the codes to the Mega2560 board, you can see that the LEDs on the LED Bar Graph flash in sequence.

## Code AnalysisÂ¶

The codes in setup() use the for loop to initialize pins 2~11 to output mode in turn.

```for(int i=2;i<=11;i++)
{
pinMode(i,OUTPUT);
}
```

The for loop is used in loop() to make the LED flash(turn on 0.5s, then turn off 0.5s) in sequence.

```for(int i=2;i<=11;i++)
{
digitalWrite(i,HIGH);
delay(500);
digitalWrite(i,LOW);
delay(500);
}
```

Refer to Part 1-1.2 Digital Write for more details about controlling the LED by using digital pins.

1.2 Digital Write