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. 

This tutorial demonstrates how to control a series of LEDs in a row, but can be applied to any series of digital outputs.

This tutorial borrows from the For Loop and Arrays tutorial as well as the Analog Input tutorial.

Step 1: What You Need?

1 x Arduino Board ( Arduino UNO R3 used in this tutorial.)
1 x LED Bar Graph Display or 10 x LEDs 
1 x Potentiometer
10 x 220 Ohm Resistors 
1 x Breadboard
1 x USB Type-B Cable 
Male-to-Male Jumper Wires


Optional
Arduino Uno R3 Acrylic Transparent Casing
Arduino Compatible UNO Ultimate Starter Kit / Learning Kit

Don't have components? Don't worry. Just click the component's name.

Step 2: Build Your Circuit.

Step 3: Upload The Code.

1. Select the Arduino board type: Select Tools >> Board >> Select your correct Arduino board used.

2. Find the port number by accessing device manager on Windows. See the section Port (COM&LPT) and look for an open port named "Arduino Uno (COMxx)". If you are using a different board, you will find a name accordingly. What matters is the xx in COMxx part. In my case, it's COM3. So my port number is 3.

Select the right port: Tools >> Port >> Select the port number.

3. You can find this code in the example of Arduino IDE.

Select File >> Examples >> 07. Display >> barGraph

Click press the "upload" button (see the button with right arrow mark).

The sketch works like this: first you read the input. You map the input value to the output range, in this case ten LEDs. Then you set up a for loop to iterate over the outputs. If the output's number in the series is lower than the mapped input range, you turn it on. If not, you turn it off.

Download:

Arduino IDE

Sources:https://www.arduino.cc/en/Tutorial/BarGraph

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Author & Editor

My Robot Education Sdn. Bhd. (Robotedu.my) was founded in 2015 as the first robotics education centre in Malaysia to provide Arduino-based robotics courses for youths. Our vision is to be able to provide robotics education to every youth in Malaysia.