Wednesday, September 7, 2022
Home Arduino Let's work with Arduino with LED Bar Graph Lesson 05

# Let’s work with Arduino with LED Bar Graph Lesson 05

Good day Today, we will talk about how to work with LED BAR GRAPH.

1. Arduino Uno board:www.daraz.lk
2. A LED BAR GRAPH: https://www.duino.lk/LED-Bar-Graph-Display-10-Segment
3. Jumper Wires: https://www.amazon.in/Jumper-Wires-Male-female-Pieces/dp/B00ZYFX6A2?th=1
4. 10 Resistors 220 Ohm: EDGELEC 100pcs 220 ohm Resistor 1/2w (0.5Watt) ±1% Tolerance Metal Film Fixed Resistor, Multiple Values of Resistance Optional

LED BAR GRAPH is a single unit consisting of 10 LEDs. It has 20 PINs with 10 PINs on each side. Therefore, we use Arrays to implement this. Multiple values ​​can be stored in an array variable. Here we will store the PIN values ​​we need on the Arduino board.

## This is how to make Arrays in Arduino.

First, we have to mention the relevant variable type and then the Array’s name. Then [] is noted next to that name.

int arrayName[];

string arrayName[];

When substituting values ​​into Array, the substitution is as follows.

``int LedPin[] = {3,4,5,6,7,8,9,10,11,12}``

Here we have used ​​the PINs connected to the Arduino UNO board.

### Now let’s turn on this LED BAR GRAPH.

First, we need to set up all the relevant PINs. For that, we use a for loop in void setup() to set it up like this.

``````for (int i=0;i<10;i++)
{
pinMode(LedPin[i], OUTPUT);
}``````

Here the initial value of int i is equal to 0 because the index value corresponding to the first value of an Array is 0. In the middle of the for loop i<10 it will execute until the value of i is less than 10 or else the number of PINs in our Array. Finally, i++ increases the value of variable i by 1 (i=i+1).

Inside pinMode(), we specify the relevant PIN and whether that PIN is INPUT or OUTPUT. Here we have given all the PINs using an Array, so we call it LedPin[i]. There, the value of i will be changed until the for loop is executed, and this pinMode will be obtained by specifying i inside the boxes. That way, all the PINs in the Array will become OUTPUT PIN.

Here, the value of I and the value coming out of that Array will change this way.

1. LedPin; = 3
2. LedPin; = 4
3. LedPin; = 5
4. LedPin; = 6
5. LedPin; = 7
6. LedPin; = 8
7. LedPin; = 9

Now let’s light this LED BAR GRAPH through the void loop. We use a for loop for that. This will light up all the ports or several related to all the values ​​in the Array we created above. We do it in the following way.

## First, we turn on all the LEDs one at a time.

``````for (int i= 0;i<10; i++)
{
digitalWrite(LedPin[i], HIGH);
delay(1000);
}``````

Every PIN from the 3rd Port to the 12th Port on the Uno board lights up once per second.

### Now let’s light each LED separately.

``````for (int i= 0;i<10; i++)
{
digitalWrite(LedPin[i], HIGH);
delay(1000);
digitalWrite(LedPin[i], LOW);
}``````

Here we make the first PIN HIGH and turn it on. Again after a delay, it turns off. This is done by a for loop, so the value of i increases by one. The LED corresponding to the next PIN will light up again. After another delay, it turns off.

# Code:

``````int LedPin[] = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 };

void setup() {
for (int i = 0; i < 10; i++) {
pinMode(LedPin[i], OUTPUT);
}
}

void loop() {
for (int i = 0; i < 10; i++) {
digitalWrite(LedPin[i], HIGH);
delay(1000);
digitalWrite(LedPin[i], LOW);
}
}``````

So, guys, we say goodbye for today. I will come back with another article like this. Don’t forget to comment on your suggestions and shortcomings. Good day

RELATED ARTICLES