How to Use an nRF24L01 Module with Arduino

Arduino, Electronics, Tutoriales

In the world of robotics and IoT, wireless communication between devices is essential. One of the most affordable and efficient modules for transmitting data over a 2.4GHz radio frequency is the nRF24L01. In this tutorial, we’ll explore how it works, the difference between its versions, and how to use it with Arduino.

🔍 What is the nRF24L01?

The nRF24L01 is a wireless transceiver module operating on the 2.4GHz ISM band (free and license-exempt). It can communicate with other nRF24 modules up to a distance of:

100 meters in open space for the standard PCB antenna version
1 km or more with the external antenna PA+LNA version

📡 nRF24L01 With vs Without Antenna

Version	Range	Stability	Power Consumption	Cost
Without antenna (PCB)	up to 100m	Medium	Low	Affordable
With external antenna (PA+LNA)	up to 1000m	High	Higher	More expensive

Recommendation:
If your project involves obstacles or distances above 50-100m, it’s better to use the external antenna version.

📑 How it Works

The nRF24L01 uses the SPI protocol to communicate with Arduino. It can operate both as a transmitter and a receiver, allowing data exchange between two or more devices.

📶 Modes:

Transmitter (TX): sends data to one or more receivers
Receiver (RX): listens for incoming data from transmitters

📝 Required Components

2 x Arduino Uno (or compatible board)
2 x nRF24L01
Jumper wires

🔌 Wiring Diagram

📦 Complete Arduino Code – Transmitter

Here’s the code to send the data:

				
					#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(9, 10); // CE, CSN

const byte address[6] = "00001";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.openWritingPipe(address);
  radio.setPALevel(RF24_PA_HIGH);
  radio.stopListening();
}

void loop() {
  const char text[] = "Hello World";
  radio.write(&text, sizeof(text));
  Serial.println("Message sent");
  delay(1000);
}

📦 Complete Arduino Code – Receiver

Here’s the code to receive the data:

				
					#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(9, 10); // CE, CSN

const byte address[6] = "00001";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.openWritingPipe(address);
  radio.setPALevel(RF24_PA_HIGH);
  radio.stopListening();
}

void loop() {
  const char text[] = "Hello World";
  radio.write(&text, sizeof(text));
  Serial.println("Message sent");
  delay(1000);
}

🔎 Breaking down the Code

Let’s review the code section by section:

📦 Include Libraries

Includes the necessary libraries for SPI and nRF24 functionality.

				
					#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

📦 Declare the radio object

Defines the CE and CSN pins used for communication.

				
					RF24 radio(9, 10);

📦 Set the Address

Defines the CE and CSN pins used for communication.

				
					const byte address[6] = "00001";

Sets a shared communication channel for both TX and RX modules. You can change this value to create independent connections.

📦 Transmitter Configuration

				
					radio.begin();
radio.openWritingPipe(address);
radio.setPALevel(RF24_PA_HIGH);
radio.stopListening();

begin() starts the module
openWritingPipe() sets the sending channel
setPALevel() sets transmission power (LOW, MEDIUM, HIGH, MAX)
stopListening() configures the module as a transmitter

📦 Receiver Configuration

				
					radio.begin();
radio.openReadingPipe(0, address);
radio.setPALevel(RF24_PA_HIGH);
radio.startListening();

openReadingPipe() opens the receiving channel
startListening() sets the module as a receiver

📦 Sending and Receiving Data

Transmitter:

				
					radio.write(&text, sizeof(text));

Receiver:

				
					if (radio.available()) {
  radio.read(&text, sizeof(text));
}

The transmitter sends data, while the receiver checks if data is available and reads it into a buffer.