Long-Range Communication with SX1278 LoRa With Arduino

LoRa (Long Range) is a wireless communication technology that is excellent for Internet of Things applications, where battery-powered devices are required to send data to a main area. It allows long-range communication with low power consumption.

It is similar to Bluetooth but has a much faster connection. You can use LoRa radios to create LoRa applications that use data handlers and health monitoring platforms to collect data about your environment and system.

Here we will introduce you to LoRa communication technology and also demonstrate how to use LoRa with Arduino. By the end of this post, you will have full knowledge of how LoRa technology works and how to use it with Arduino to build your own IoT Projects including data collection, controlling devices, and monitoring sensors.

Required Material

To interface a LoRa module with Arduino, you will need the following components:

Arduino board
LoRa module (SX1278 or SX1276)
Breadboard
Jumper wires
Antenna (for the LoRa module)

What is LoRa Communication

LoRa technology is a wireless communication technology that allows long-range communication with the lowest power consumption. The range is up to 10 kilometers in open spaces and much less when there are obstacles between the transmitter and the receiver.

It uses spread ~~spectrum modulation~~ techniques to send data over long distances without the need for a high-power transmission. LoRa is optimized for sending small packets of data and is often used in IoT applications such as sensors and devices.

The LoRa® modulation technique was created by a French startup called Cycleo in 2010. Two years later, in 2012, Semtech acquired Cycleo and took over the technology.

LoRa is a radio communication technology that is characterized by allowing transmission over extended ranges and low energy consumption. It is an excellent choice for use in IoT projects and embedded systems since its low energy consumption allows it to be powered only by batteries.

One of the main capacities of LoRa technology is able to provide long-range and low-power communications. LoRa devices are used to collect data from sensors or devices and transmit that data wirelessly to a LoRa gateway, which can then forward the data to a server or cloud for storage and processing.

The following table shows some of the primary characteristics of the LoRa protocol.

Feature	Description
Modulation	Chirp Spread Spectrum (CSS)
Frequency Bands	Sub-GHz bands (433 MHz, 868 MHz, 915 MHz)
Range	Up to 10 km in rural areas, 1-3 km in urban areas
Data Rate	0.3 kbps – 50 kbps
Capacity	Can support thousands of devices in a single network
Battery Life	Can operate on a single battery for several years
Security	End-to-end AES encryption
Interference Immunity	Can operate in noisy RF environments
Network Topology	Supports star, mesh, and point-to-point topologies
Cost	Low-cost hardware and infrastructure

LoRa® can work on three specific frequency bands that are reserved internationally for non-communication uses, known as ISM (Industrial, Scientific, and Medical) bands. These frequency bands are 433 MHz, 868 MHz, and 915 MHz, and they do not demand a license to use them.

Do you think if LoRa is so good, why don’t I use it instead of Wi-Fi to transfer my data?

While LoRa technology has many advantages, it is important to note that it is not a replacement for WiFi, and there are certain situations where WiFi may be a better option for sending data

Speed: LoRa is optimized for low data rates and can transmit data at rates of up to a few hundred kilobits per second. Wi-Fi, in comparison, can transmit data at rates of several megabits per second, making it much faster.
Range: LoRa is designed for long-range communication, but its range is limited by factors such as geography, buildings, and signals from other devices. Wi-Fi generally has a shorter range than LoRa, but it can be easily extended with the use of repeaters and access points.
Compatibility: Wi-Fi is the most widely adopted standard for wireless networking, with most devices supporting it. LoRa, on the other hand, is a fairly new technology that may only be supported by a limited number of devices.
Cost: LoRa technology is commonly used in devices and applications, the cost of LoRa modules and gateways may become more expensive if you need to cover a large range. for larger applications, it is advisable to flip sides to Wi-Fi.

The image below presents this well

Semtech LoRa SX1278 Transceiver

LoRa is a wireless protocol developed by Semtech that uses chirp spread-spectrum (CSS) modulation to perform long-range communication with low power consumption. The CSS modulation technique involves sending signals that vary in frequency over time, which makes the signal resistant to interference and noise.

LoRa is a great application that requires long-range wireless communication with low power consumption.

SX1278 Pin Description

Pin	Pin Name	Pin Description
1	GND	Ground (0 V)
2	D101	Digital I/O
3	D102	Digital I/O
4	D103	Digital I/O
5	VCC	Power (3.6 V Maximum)
6	MISO	SPI Data Output
7	MOSI	SPI Data Input
8	SLCK	SPI Clock
9	NSS	SPI Chip Select
10	D100	Digital I/O
11	REST	Reset
12	GND	Ground (0 V)
13	GND	Ground (0 V/ANT GND)
14	ANT	Antenna (50-Ω Impedance)

Block Diagram of SX1278 Chip

SX1278 Features

LoRa Model
Operating Voltage: 1.8-3.7v
Operating Frequency: 433Mhz
Half-Duplex SPI communication
Modulation Technique FSK, GFSK, MSK, GMSK, LoRa
Packet size: 256 byte
Sensitivity: -148db

SX1278 LoRa breakout module

The SX1278 LoRa module is a wireless transceiver module that operates on the Long Range (LoRa) Communication process. This specific model operates at the 433MHz frequency & the module uses SX1278 IC which is designed to deliver low-power, long-range wireless communication.

The SX1278 has a decent sensitivity of –148 dBm with a calm power output of +20 dBm and a long transmission distance. the module communicates with the microcontroller through an SPI interface, allowing for easy-to-connect.

LoRa SX1278 Pinout

GND: Ground pin
VCC: Power supply pin (1.8-3.7v)
MOSI: Master Out Slave In pin for SPI interface
MISO: Master In Slave Out pin for SPI interface
SCK: Clock pin for SPI interface
NSS: Slave Select pin for SPI interface
DIO0-DIO5: Digital Input Output pins for LoRa data transmission and reception
RESET: Reset the pin for the SX1278 chip
CLK: Clock pin for the SX1278 chip
ANT: Antenna pin for transmitting and receiving signals

Features of SX1278 LoRa Module

LoRa Spread Spectrum modulation technology
Supports FSK, GFSK, MSK, GMSK, LoRa, and OOK modulation methods
Constant RF power output at + 20dBm-100mW voltage change
Half-duplex SPI communication
Automatic RF signal detection
CAD mode, and very high-speed AFC
Packet engine with CRC up to 256 bytes

Specifications of SX1278 LoRa

Frequency range: 433MHz
Sensitivity: -148dBm
Output power: up to 20dBm (100mW)
Modulation: LoRa
Modulation bandwidth: 125kHz, 250kHz, 500kHz
Spreading factor: 6 to 12
Maximum data rate: 300kbps
Operating voltage: 1.8~3.6V DC
Current consumption: 120mA (transmission), 15mA (receive), 1.5uA (sleep mode)
Interface: SPI
Dimensions: 16mm x 16mm

Application of SX1278 LoRa module

Internet of Things (IoT)applications
Wireless sensor networks
Smart agriculture and farming
Asset tracking
Industrial monitoring
Smart city applications,
Home automation
Security systems
Environmental monitoring

LoRa frequency bands by country

LoRa operates in specific frequency bands, which are available for unlicensed use in different regions around the world. The frequency bands and maximum power levels authorized for LoRa transmissions by region. It’s important to verify suitable rules before using LoRa devices.

Country	LoRa Frequency Band
United States	902 – 928 MHz
Canada	915 MHz
Mexico	902 – 928 MHz
Brazil	902 – 904 MHz and 915 – 928 MHz
European Union	863 – 870 MHz
Russia	864 – 870 MHz and 868 – 869 MHz
India	865 – 867 MHz
China	433 MHz, 470 – 510 MHz, 779 – 787 MHz, and 470 – 510 MHz
Japan	920 – 928 MHz
South Korea	920 – 923 MHz
Australia	915 – 928 MHz
New Zealand	915 – 928 MHz

Accordingly, it’s always recommended to check the local laws before using LoRa devices.

The LoRa module that I am currently using is the SX1278 Ra-02, which operates on the 433MHz frequency. However, as a resident of India, I am familiar with the unlicensed frequency range approved for use here band between 865MHz to 867MHz. ,

I am not allowed to use the 433MHz frequency module, such as the SX1278 Ra-02 module that I am currently using, for a short period unless it is for educational purposes.

Interfacing SX1278 LoRa With Arduino

The SX1278 LoRa module can be connected to the Arduino using the following pins:

Code & Library for LoRa Module

Install the LoRa Arduino library

To use the SX1278 LoRa module With Arduino, you will need to download the LoRa library first. You can download the library from this link: https://github.com/sandeepmistry/arduino-LoRa, then extract the downloaded file to the libraries folder of your Arduino IDE.

Source Code for Transmitter & Receiver

Transmitter Example Code

#include <SPI.h>
#include <LoRa.h>

int counter = 0;

void setup() {
  Serial.begin(9600);
  while (!Serial);

  Serial.println("LoRa Sender");

  if (!LoRa.begin(433E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }

  LoRa.setTxPower(20);
  
}

void loop() {
  Serial.print("Sending packet: ");
  Serial.println(counter);

  // send packet
  LoRa.beginPacket();
  LoRa.print("hello ");
  LoRa.print(counter);
  LoRa.endPacket();

  counter++;

  delay(5000);
}

#include <SPI.h>

#include <LoRa.h>

int counter = 0;

void setup() {

Serial.begin(9600);

while (!Serial);

Serial.println("LoRa Sender");

if (!LoRa.begin(433E6)) {

Serial.println("Starting LoRa failed!");

while (1);

}

LoRa.setTxPower(20);

}

void loop() {

Serial.print("Sending packet: ");

Serial.println(counter);

// send packet

LoRa.beginPacket();

LoRa.print("hello ");

LoRa.print(counter);

LoRa.endPacket();

counter++;

delay(5000);

}

Receiver Example Code

#include <LoRa.h>


void setup() {

  Serial.begin(9600);

  while (!Serial);


  Serial.println("LoRa Receiver");


  if (!LoRa.begin(433E6)) {

    Serial.println("Starting LoRa failed!");

    while (1);

  }

}


void loop() {

  // try to parse packet

  int packetSize = LoRa.parsePacket();

  if (packetSize) {

    // received a packet

    Serial.print("Received packet '");


    // read packet

    while (LoRa.available()) {

      Serial.print((char)LoRa.read());

    }


    // print RSSI of packet

    Serial.print("' with RSSI ");

    Serial.println(LoRa.packetRssi());

  }

}

#include <LoRa.h>

void setup() {

Serial.begin(9600);

while (!Serial);

Serial.println("LoRa Receiver");

if (!LoRa.begin(433E6)) {

Serial.println("Starting LoRa failed!");

while (1);

}

void loop() {

// try to parse packet

int packetSize = LoRa.parsePacket();

if (packetSize) {

// received a packet

Serial.print("Received packet '");

// read packet

while (LoRa.available()) {

Serial.print((char)LoRa.read());

}

// print RSSI of packet

Serial.print("' with RSSI ");

Serial.println(LoRa.packetRssi());

}

Control LED Using SX1278 LoRa Module With Arduino

To control the LED using the SX1278 LoRa module, First, connect an LED and button to the Arduino

Transmitter Wiring Diagram Using Sx1278 Lora

LoRa –> Arduino

GND to GND
VCC to 3.3V
MOSI to pin 11
MISO to pin 12
SCK to pin 13
NSS to pin 10
DIO0 to pin 2
RST to pin 9

Switch –> Arduino

GND –> GND
Out –> 3

Receiver Wiring Diagram Using Sx1278 Lora

LoRa Module –> Arduino

GND to GND
VCC to 3.3V
MOSI to pin 11
MISO to pin 12
SCK to pin 13
NSS to pin 10
DIO0 to pin 2
RST to pin 9

Signal Green LED–> Arduino

Negative Terminal –> GND
Positive Terminal –> 3

Bulb –> Arduino

GND –> GND
VCC –> 4

LoRa Arduino code

Sx1278 Lora Transmitter Code

#include <LoRa.h> 
//int pot = A0;
const int SW1 = 3;


int SyncWord = 0x22;
 
void setup() {
  Serial.begin(9600);
  pinMode(SW1,INPUT_PULLUP);
  
  cli();                                    //stop interrupts
                                            //set timer1 interrupt at 1Hz = 1sec
  TCCR1A = 0;                               // set entire TCCR1A register to 0
  TCCR1B = 0;                               // same for TCCR1B
  TCNT1  = 0;                               // initialize counter value to 0
                                            // set compare match register for 1hz increments
  OCR1A = 15624;                            // = (16*10^6) / (1*1024) - 1 (must be <65536)
                                            
  TCCR1B |= (1 << WGM12);                   // turn on CTC mode                                      
  TCCR1B |= (1 << CS12) | (1 << CS10);      // Set CS10 and CS12 bits for 1024 prescaler                                          
  TIMSK1 |= (1 << OCIE1A);                  // enable timer compare interrupt

  sei();                                    //allow interrupts
  
  while (!Serial);  
  Serial.println("LoRa Sender");
  if (!LoRa.begin(433E6)) { // or 915E6, the MHz speed of yout module
    Serial.println("Starting LoRa failed!");
    while (1);
  }
  
  LoRa.setSpreadingFactor(12);           // ranges from 6-12,default 7 see API docs
  LoRa.setSignalBandwidth(62.5E3 );           // for -139dB (page - 112)
  LoRa.setCodingRate4(8);                   // for -139dB (page - 112)
  LoRa.setSyncWord(SyncWord);
/*
  Serial.print("current spreading factor : ");
  Serial.println(LoRa.getSpreadingFactor());
  Serial.print("current bandwidth : ");
  Serial.println(LoRa.getSignalBandwidth());
  Serial.println("LoRa init succeeded.");
  */
}

int priviousSwitchValue1 = 1;
int liveSwitchValue1 = 0;
bool switchPressFlag1 = false;
bool gLedPin = 0;

int data = 1;

void loop() {
  //static int data = 1;
  
  liveSwitchValue1 = digitalRead(SW1);
  if( (liveSwitchValue1 == 0) and (switchPressFlag1 == false) )
  {
    delay(50);
    data = 11;
    Serial.println("11");
    switchPressFlag1 = true;
    priviousSwitchValue1 = !priviousSwitchValue1;

    LoRa.beginPacket();  
    LoRa.print(data);
    LoRa.endPacket();
  }
  if( (liveSwitchValue1 == 1) and (switchPressFlag1 == true) )
  {
    delay(50);
    data = 22;
    Serial.println("22");
    switchPressFlag1 = false;
    LoRa.beginPacket();  
    LoRa.print(data);
    LoRa.endPacket();
  }
   
  
  if(gLedPin == 1)
  {
    data = 55;
    Serial.println("55");
    gLedPin = 0;
    LoRa.beginPacket();  
    LoRa.print(data);
    LoRa.endPacket();
  }
  
  // LoRa.beginPacket();  
  // LoRa.print(data);
  // LoRa.endPacket();
}

ISR(TIMER1_COMPA_vect){//timer1 interrupt 1Hz toggles pin 13 (LED)
//generates pulse wave of frequency 1Hz/2 = 0.5kHz (takes two cycles for full wave- toggle high then toggle low)
  static volatile int ledFlag = 0;
  if(++ledFlag >= 5)
  {
    gLedPin = 1;
    ledFlag = 0;
  }
}

100

101

102

103

104

#include <LoRa.h>

//int pot = A0;

const int SW1 = 3;

int SyncWord = 0x22;

void setup() {

Serial.begin(9600);

pinMode(SW1,INPUT_PULLUP);

cli(); //stop interrupts

//set timer1 interrupt at 1Hz = 1sec

TCCR1A = 0; // set entire TCCR1A register to 0

TCCR1B = 0; // same for TCCR1B

TCNT1 = 0; // initialize counter value to 0

// set compare match register for 1hz increments

OCR1A = 15624; // = (16*10^6) / (1*1024) - 1 (must be <65536)

TCCR1B |= (1 << WGM12); // turn on CTC mode

TCCR1B |= (1 << CS12) | (1 << CS10); // Set CS10 and CS12 bits for 1024 prescaler

TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt

sei(); //allow interrupts

while (!Serial);

Serial.println("LoRa Sender");

if (!LoRa.begin(433E6)) { // or 915E6, the MHz speed of yout module

Serial.println("Starting LoRa failed!");

while (1);

}

LoRa.setSpreadingFactor(12); // ranges from 6-12,default 7 see API docs

LoRa.setSignalBandwidth(62.5E3 ); // for -139dB (page - 112)

LoRa.setCodingRate4(8); // for -139dB (page - 112)

LoRa.setSyncWord(SyncWord);

Serial.print("current spreading factor : ");

Serial.println(LoRa.getSpreadingFactor());

Serial.print("current bandwidth : ");

Serial.println(LoRa.getSignalBandwidth());

Serial.println("LoRa init succeeded.");

}

int priviousSwitchValue1 = 1;

int liveSwitchValue1 = 0;

bool switchPressFlag1 = false;

bool gLedPin = 0;

int data = 1;

void loop() {

//static int data = 1;

liveSwitchValue1 = digitalRead(SW1);

if( (liveSwitchValue1 == 0) and (switchPressFlag1 == false) )

{

delay(50);

data = 11;

Serial.println("11");

switchPressFlag1 = true;

priviousSwitchValue1 = !priviousSwitchValue1;

LoRa.beginPacket();

LoRa.print(data);

LoRa.endPacket();

}

if( (liveSwitchValue1 == 1) and (switchPressFlag1 == true) )

{

delay(50);

data = 22;

Serial.println("22");

switchPressFlag1 = false;

LoRa.beginPacket();

LoRa.print(data);

LoRa.endPacket();

}

if(gLedPin == 1)

{

data = 55;

Serial.println("55");

gLedPin = 0;

LoRa.beginPacket();

LoRa.print(data);

LoRa.endPacket();

}

// LoRa.beginPacket();

// LoRa.print(data);

// LoRa.endPacket();

}

ISR(TIMER1_COMPA_vect){//timer1 interrupt 1Hz toggles pin 13 (LED)

//generates pulse wave of frequency 1Hz/2 = 0.5kHz (takes two cycles for full wave- toggle high then toggle low)

static volatile int ledFlag = 0;

if(++ledFlag >= 5)

{

gLedPin = 1;

ledFlag = 0;

}

Sx1278 Lora Receiver Code

#include <LoRa.h> 

const int Signal_LED = 3;   // indicator LED
const int LED = 4;   // relay 1

String inString = "";    // string to hold input
int val = 0;
int SyncWord = 0x22;
 
void setup() {
  Serial.begin(9600);
  pinMode(Signal_LED,OUTPUT);
  pinMode(LED,OUTPUT);
  
  digitalWrite(Signal_LED , LOW); 
  digitalWrite(LED , HIGH);
  
  while (!Serial);
  Serial.println("LoRa Receiver");
  if (!LoRa.begin(433E6)) { // or 915E6
    Serial.println("Starting LoRa failed!");
    while (1);
  }
   LoRa.setSpreadingFactor(12);           // ranges from 6-12,default 7 see API docs
   LoRa.setSignalBandwidth(62.5E3);           // for -139dB (page - 112)
   LoRa.setCodingRate4(8);                   // for -139dB (page - 112)
   LoRa.setSyncWord(SyncWord);           // ranges from 0-0xFF, default 0x12, see API docs
/*
  Serial.print("current spreading factor : ");
  Serial.println(LoRa.getSpreadingFactor());
  Serial.print("current bandwidth : ");
  Serial.println(LoRa.getSignalBandwidth());
  Serial.println("LoRa init succeeded.");
  */
}
bool i=0;
int priviousValue = 0;
int liveValue = 0;

void loop() { 
  // try to parse packet
  int packetSize = LoRa.parsePacket();
  if (packetSize) { 
    // read packet    
    while (LoRa.available())
    {
      int inChar = LoRa.read();
      inString += (char)inChar;
      val = inString.toInt();  
      digitalWrite(Signal_LED , HIGH);
      delay(10);
      digitalWrite(Signal_LED , LOW);
      delay(10);     
    }
    inString = "";     
    LoRa.packetRssi();    
  }
  
  Serial.println(val);  
  liveValue = val;
    
  if(priviousValue != liveValue)
  {
    priviousValue = liveValue;
  
    if(val == 11)
    {
      digitalWrite(LED , LOW);
    }
    
    if(val == 22)
    {
      digitalWrite(LED , HIGH);
    }
  
    
  }
  delay(50);
}

#include <LoRa.h>

const int Signal_LED = 3; // indicator LED

const int LED = 4; // relay 1

String inString = ""; // string to hold input

int val = 0;

int SyncWord = 0x22;

void setup() {

Serial.begin(9600);

pinMode(Signal_LED,OUTPUT);

pinMode(LED,OUTPUT);

digitalWrite(Signal_LED , LOW);

digitalWrite(LED , HIGH);

while (!Serial);

Serial.println("LoRa Receiver");

if (!LoRa.begin(433E6)) { // or 915E6

Serial.println("Starting LoRa failed!");

while (1);

}

LoRa.setSpreadingFactor(12); // ranges from 6-12,default 7 see API docs

LoRa.setSignalBandwidth(62.5E3); // for -139dB (page - 112)

LoRa.setCodingRate4(8); // for -139dB (page - 112)

LoRa.setSyncWord(SyncWord); // ranges from 0-0xFF, default 0x12, see API docs

Serial.print("current spreading factor : ");

Serial.println(LoRa.getSpreadingFactor());

Serial.print("current bandwidth : ");

Serial.println(LoRa.getSignalBandwidth());

Serial.println("LoRa init succeeded.");

}

bool i=0;

int priviousValue = 0;

int liveValue = 0;

void loop() {

// try to parse packet

int packetSize = LoRa.parsePacket();

if (packetSize) {

// read packet

while (LoRa.available())

{

int inChar = LoRa.read();

inString += (char)inChar;

val = inString.toInt();

digitalWrite(Signal_LED , HIGH);

delay(10);

digitalWrite(Signal_LED , LOW);

delay(10);

}

inString = "";

LoRa.packetRssi();

}

Serial.println(val);

liveValue = val;

if(priviousValue != liveValue)

{

priviousValue = liveValue;

if(val == 11)

{

digitalWrite(LED , LOW);

}

if(val == 22)

{

digitalWrite(LED , HIGH);

}

delay(50);

}

Conclusion – SX1278 LoRA With Arduino

In conclusion, the SX1278 LoRa module is a perfect choice for long-range wireless communication tasks that require low power consumption and high data rates.

Introduction to LoRa Communication and How to use it with Arduino

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LoRa GPS Based IoT Geo-Fencing Using Arduino, and ESP32

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Introduction to LoRa Communication and How to use it with Arduino

Required Material

What is LoRa Communication

Semtech LoRa SX1278 Transceiver

SX1278 Pin Description

Block Diagram of SX1278 Chip

SX1278 Features

SX1278 LoRa breakout module

LoRa SX1278 Pinout

Features of SX1278 LoRa Module

Specifications of SX1278 LoRa

Application of SX1278 LoRa module

LoRa frequency bands by country

Interfacing SX1278 LoRa With Arduino

Code & Library for LoRa Module

Install the LoRa Arduino library

Source Code for Transmitter & Receiver

Transmitter Example Code

Receiver Example Code

Control LED Using SX1278 LoRa Module With Arduino

Transmitter Wiring Diagram Using Sx1278 Lora

Receiver Wiring Diagram Using Sx1278 Lora

LoRa Arduino code

Sx1278 Lora Transmitter Code

Sx1278 Lora Receiver Code

Conclusion – SX1278 LoRA With Arduino

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