How to use digitalRead in Arduino ?

How to use digitalRead in Arduino ?

• As I have explained in the above section that Arduino UNO has 14 digital pins in total starting from 0 to 13 as shown in below figure:

• So, you can see in the above figure that we have RXD at 0 which is sued for Serial receiving and then we have TXD at 1 used for Serial writing.
• So, these pins from 0 to 13 are all digital and after these digital Pins we have GND.
• Now I hope you have got the idea of digital Pins.

• Next thing is How to use these digital Pins, normally we connect different digital sensors with these digital Pins.
• For example, I have a digital Sensor named as Vibration Sensor. This sensor gives HIGH when it feels vibrations and gives LOW in normal condition.
• So, I am gonna connect the Signal Pin of this Sensor with any digital Pin of Arduino.
• Now, coming towards digitalRead command, this digitalRead command is used in Arduino for reading the status of digital Pins on Arduino.
• So, when we want to read whether the digital Pin of Arduino is HIGH or LOW, we use this digitalRead command.
• The syntax of digitalRead is as follows:

int Reading = digitalRead (int PinNumber);

• digitalRead command takes one input which is the value of the Pin, like if you wanna read the digital status of Pin # 8 then you have to enter 8 in the small brackets of digitalRead.
• digital Read returns Boolean data which is either HIGH or LOW and it is saved in the integer variable which I have named Reading in the above syntax. We have discussed it in Arduino Datatypes.
• So, let's have a look at the example of digitalRead:

Reading = digitalRead (8);

• In the above example, I am reading the status of digital Pin # 8 of Arduino and saving it value in the Reading variable.
• So, I hope now you have understood completely How to use the digital Read in Arduino.

• One important thing to note here is that because we are reading the data from digital Pin so that digital Pin must have to be an input.
• So, you need to declare that Pin as an input.

• So, let's have a look at a small code in which we will read the status of pin # 8 of Arduino and then display its status on Serial Monitor.
• I hope you have already read How to write Arduino Code and knows its basics.

int Pin = 8; // Initializing Arduino Pin
int Reading;

void setup() {
  pinMode(Pin, INPUT); // Declaring Arduino Pin as an Input
}

void loop() {
  Reading = digitalRead(Pin); // Reading status of Arduino digital Pin
  
  if(Reading == HIGH)
  {
    Serial.println("HIGH");
  }

  if(Reading == LOW)
  {
    Serial.println("LOW");
  }
 
}

Summary

• digitalRead is used to read the status of any digital Pin in Arduino.
• We have to give the digital Pin number in the small brackets.

• Syntax of digital Read is:

int Reading = digitalRead (int PinNumber);

Return:

• digitalRead returns HIGH or LOW depending on the status of corresponding digital Pin.

Reading = digitalRead (8);

Restriction:

• Before reading status of any digital Pin, we have to first declare that Pin as an input.:

pinMode(8,INPUT);