Wireless Lora RF Receiver Module Ra-02 Ai-Thinker 10KM 433MHZ SX1278

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The SX1278 LoRa RF Module is a cutting-edge RF (Radio Frequency) technology module designed for long-range communication. It utilizes the LoRa modulation scheme and operates using the SPI (Serial Peripheral Interface) communication protocol, making it compatible with various microcontrollers that support SPI. To ensure proper functionality, it is crucial to connect an antenna to the module, as operating without one may result in permanent damage. The module requires a power supply of 3.3V and utilizes the SPI lines for communication. By employing the Lora spectrum communication technique, it achieves an impressive range of up to 10 kilometers. However, it's important to note that this extended range is contingent upon using a specific channel with a bandwidth of 1MHz.


Package Includes:

  • 1 x SX1278 LoRa RF Module



  • RF Technology and LoRa Modulation: Utilizes advanced RF technology for long-range communication, Implements LoRa modulation scheme for reliable and efficient communication.
  • SPI Communication Protocol: Works seamlessly with microcontrollers that support SPI communication.
  • Antenna Requirement: Mandatory to use an antenna for proper functioning and to prevent module damage.
  • Extended Range and Bandwidth Requirement: Offers a maximum communication range of up to 10 kilometers. Utilizes a specific channel with 1MHz bandwidth for optimal performance.
  • Frequency Range: Operates within the 433MHz frequency range.
  • Sensitivity: High sensitivity of -136dBm for reliable reception of signals.
  • Output Power: Provides a maximum output power of +20dBm for strong signal transmission.
  • Data Rate: Supports data rates of up to 300 kbps for efficient data transfer.
  • Blocking Immunity: Excellent blocking immunity to maintain communication integrity in noisy environments.
  • Preamble Detection: Capable of detecting preamble signals for efficient packet reception.
  • RF Sense and CAD Monitor: Automatically monitors RF activity and utilizes CAD (Channel Activity Detection) for interference avoidance.
  • Clock Recovery: Built-in bit synchronizer for precise clock recovery during data transmission.
  • Packet Engine: Equipped with a packet engine that can handle packets up to 256 bytes with CRC (Cyclic Redundancy Check) for data integrity.
  • Built-in Temperature Sensor: Includes a temperature sensor for monitoring the module's temperature.
  • Low Power Standby: Consumes only 1uA of standby current when not actively transmitting or receiving data.



The SX1278 LoRa RF Module is an advanced and versatile module that harnesses the latest RF technology and incorporates the LoRa modulation scheme, enabling reliable and efficient long-range communication. With seamless compatibility with microcontrollers supporting SPI communication protocol, it offers easy integration into various systems and applications. To ensure optimal performance and prevent module damage, it is mandatory to use an antenna along with the module. Operating on a 3.3V power supply, the module delivers an impressive communication range of up to 10 kilometers, making it suitable for applications requiring extended coverage. With its specific channel and 1MHz bandwidth requirement, the SX1278 LoRa RF Module optimizes communication performance, ensuring efficient data transmission with minimal interference. Its high sensitivity allows for reliable reception of signals even in challenging environments. The module boasts a maximum output power of +20dBm, ensuring strong signal transmission over long distances. It supports data rates of up to 300 kbps, facilitating efficient data transfer for various applications. The wide dynamic range RSSI provides accurate measurement of signal strength, enhancing overall communication reliability. the module features excellent blocking immunity, preamble detection for efficient packet reception, and automatic RF sense and CAD monitor for interference avoidance. The built-in clock recovery and packet engine capabilities ensure precise synchronization and data integrity during transmission. the SX1278 LoRa RF Module is designed for power efficiency, consuming only 1uA of standby current when not actively transmitting or receiving data.


Principle of Work:

LoRa (Long Range) is a wireless communication technology that enables long-range and low-power communication between devices. The SX1278 LoRa RF Module is designed to work with this technology. this is  how LoRa works and how the module operates:

  1. LoRa Technology:

    • Modulation: LoRa utilizes a modulation scheme called chirp spread spectrum (CSS). Information is encoded using chirp signals, which are gradual frequency changes over time.
    • Chirp Signal: Before sending a message, the LoRa transmitter sends out a chirp signal to check if the channel is clear for transmission.
    • Preamble Detection: The LoRa receiver detects the preamble chirp from the transmitter, which indicates the start of a message.
    • Reverse Chirp: The end of the preamble is signaled by a reverse chirp, indicating to the transmitter that it is clear to begin transmission.
    • Robustness: LoRa modulation is highly resistant to noise and can overcome obstacles, making it suitable for long-range communication with low power consumption.
  2. SX1278 LoRa RF Module:

    • RF Transceiver: The module includes an RF transceiver, which is responsible for transmitting and receiving radio signals. It operates within the specified frequency range (e.g., 433MHz) and incorporates advanced RF technology to achieve long-range communication.
    • LoRa Modulation: The module utilizes the LoRa modulation scheme, based on the chirp spread spectrum (CSS), for efficient and robust communication. The modulation process involves encoding data into chirp signals, which are gradual frequency changes over time.
    • SPI Communication Protocol: The module employs the Serial Peripheral Interface (SPI) communication protocol to interface with microcontrollers or other devices. This allows for seamless integration and easy control of the module's functionalities.
    • Antenna Connection: The module requires an antenna to be connected for proper functioning. The antenna enables the transmission and reception of radio signals, ensuring efficient communication and preventing potential damage to the module.
    • Power Supply: The module operates on a 3.3V power supply, which needs to be provided for its operation. The power supply ensures that the internal components of the module receive the necessary electrical power to function correctly.
    • Data Transmission and Reception: The module supports data transmission and reception at configurable data rates, up to a maximum of 300 kbps. It includes a packet engine that can handle packets up to 256 bytes, incorporating CRC (Cyclic Redundancy Check) for data integrity.
    • Sensitivity and Output Power: The module has a high sensitivity of -136dBm, enabling it to receive weak signals from long distances. It can also provide a maximum output power of +20dBm, allowing for strong signal transmission to reach far distances.
    • Signal Processing and Control: The module includes various signal processing and control mechanisms internally. It incorporates features such as dynamic range RSSI (Received Signal Strength Indication) for accurate signal strength measurement, blocking immunity for reliable communication in noisy environments, and preamble detection for efficient packet reception.
  3. The minimum number of SX1278 LoRa RF Modules needed would depend on the specific application and the desired functionality. In general, you would need at least two modules to establish a basic communication link between two devices. One module would act as the transmitter, while the other would function as the receiver. For example, if you are building a simple point-to-point communication system, two modules would suffice—one module for each end of the communication link. However, if you are implementing a more complex network or mesh topology where multiple devices communicate with each other, the number of modules required would depend on the specific network architecture and the number of devices involved.


Pinout of the Sensor:

  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)



  1. IoT Applications: The module is widely used in Internet of Things (IoT) applications where long-range communication is required for connecting and exchanging data between IoT devices, such as sensors, actuators, and gateways.
  2. Home and Building Automation: It can be employed in home and building automation systems for remote monitoring, control, and management of devices and systems, including smart lighting, HVAC (Heating, Ventilation, and Air Conditioning), security systems, and energy management.
  3. Long-Range Communication: The module's extended range capability makes it suitable for applications that require long-distance communication, such as remote monitoring in agriculture, environmental monitoring, asset tracking, and logistics.
  4. Mesh or Star Topology Networks: It is used in creating mesh or star topology networks where multiple devices communicate with each other over long distances. This is beneficial for applications like smart cities, smart grids, and industrial automation.
  5. Industrial Monitoring and Control: The module finds applications in industrial environments for monitoring and controlling various parameters, such as machine health, process monitoring, remote equipment management, and asset tracking.
  6. Environmental Monitoring: It can be utilized for environmental monitoring applications, including air quality monitoring, weather stations, water quality monitoring, and wildlife tracking.
  7. Smart Metering: The module can be integrated into smart metering systems for remote meter reading, utility monitoring, and smart grid communication.
  8. Agriculture and Farming: It finds applications in agricultural practices, such as soil moisture monitoring, crop monitoring, irrigation control, and livestock tracking.
  9. Security Systems: The module can be used in security systems for long-range communication between security devices, such as intrusion detection sensors, surveillance cameras, and access control systems.
  10. Amateur Radio: Enthusiasts in the amateur radio community also utilize the SX1278 LoRa RF Module for long-range communication experiments, ham radio networks, and amateur radio projects.



Connections as you see in the pics and be careful to connect the module only to 3.3v not to 5v. 



You will need to install  the LoRa library by Sandeep Mistry, you can follow these steps:

  1. Open the Arduino IDE.
  2. Go to "Sketch" in the menu bar, then navigate to "Include Library" and select "Manage Libraries."
  3. The Library Manager window will open. In the search box, type "LoRa" and press Enter.
  4. Look for the "LoRa by Sandeep Mistry" library in the search results.
  5. Click on the library, and a "Install" button will appear. Click on "Install" to begin the installation process.
  6. Wait for the installation to complete. You'll see a progress bar indicating the status of the installation.
  7. Once the installation is finished, you can close the Library Manager.



The next sample codes provide a sender code that reads an analog value from a potentiometer and transmits it using LoRa, while the receiver code listens for LoRa packets, retrieves the transmitted value, and adjusts the brightness of an LED accordingly:

Transmitter code:

>#include "SPI.h"
#include "LoRa.h" 
int pot = A0;
void setup() {
  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);
void loop() {
  int val = map(analogRead(pot),0,1024,0,255);


Receiver Code:

#include "SPI.h"
#include "LoRa.h" 
int LED = 3;
String inString = "";    // string to hold input
int val = 0;
void setup() {
  while (!Serial);
  Serial.println("LoRa Receiver");
  if (!LoRa.begin(433E6)) { // or 915E6
    Serial.println("Starting LoRa failed!");
    while (1);
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();       
    inString = "";     
  analogWrite(LED, val);


Sender Code:

  1. Initializes the Serial communication and sets the analog input pin (A0) as an input.
  2. Checks for Serial communication readiness and prints a message on the serial monitor.
  3. Initializes the LoRa module with a frequency of 433MHz.
  4. Reads an analog value from the potentiometer connected to pin A0.
  5. Maps the analog value to a range of 0-255.
  6. Begins a LoRa packet transmission.
  7. Sends the mapped value as a payload in the LoRa packet.
  8. Ends the LoRa packet transmission.
  9. Delays for 50 milliseconds before repeating the process.

Receiver Code:

  1. Initializes the Serial communication and sets an LED pin (3) as an output.
  2. Checks for Serial communication readiness and prints a message on the serial monitor.
  3. Initializes the LoRa module with a frequency of 433MHz.
  4. Enters the main loop.
  5. Attempts to parse an incoming LoRa packet.
  6. If a packet is received, reads the packet data byte by byte and stores it in a string variable (inString).
  7. Converts the string value to an integer (val).
  8. Clears the string variable (inString).
  9. Retrieves the RSSI (Received Signal Strength Indicator) of the received packet.
  10. Prints the value (val) on the serial monitor.
  11. Adjusts the brightness of the LED based on the received value using analogWrite().


Technical Details:

  • Frequency range: 433MHz
  • Modulation: FSK/GFSK/MSK/LoRa
  • Sensitivity: -136dBm
  • VCC: 3.3v only
  • Output Power: +20dBm
  • Data Rate: <300 kbps
  • Dynamic Range RSSI: 127dB
  • Excellent blocking immunity
  • Preamble detection
  • Automatic RF Sense and CAD monitor
  • Built-in bit synchronizer for clock recovery
  • Packet engine up to 256 bytes with CRC
  • Working Temperature: -40°C ~ +80°C
  • Built-in temperature sensor
  • Standby current: 1uA



More info 



The Ra-02 Ai-Thinker SX1278 and RFM95 916MHz modules are both popular options for long-range communication using LoRa technology, but they have some differences: modules:

  1. Frequency Range:

    • Ra-02 Ai-Thinker SX1278: Operates at a frequency range of 433MHz.
    • RFM95 916MHz: Operates at a frequency range of 916MHz.
  2. Maximum Communication Range:

    • Ra-02 Ai-Thinker SX1278: Offers a maximum communication range of up to 10 kilometers.
    • RFM95 916MHz: Offers a maximum communication range that can exceed several kilometers, depending on the environment and other factors.
  3. Bandwidth:

    • Ra-02 Ai-Thinker SX1278: Utilizes a specific channel with 1MHz bandwidth.
    • RFM95 916MHz: Supports configurable bandwidth options, typically ranging from 7.8kHz to 500kHz.
  4. Sensitivity and Output Power:

    • Ra-02 Ai-Thinker SX1278: Provides a high sensitivity of -136dBm for reliable signal reception and a maximum output power of +20dBm for strong signal transmission.
    • RFM95 916MHz: Offers a high sensitivity similar to the SX1278 module, and the maximum output power can vary depending on the specific version of the RFM95 module used.
  5. Compatibility:

    • Ra-02 Ai-Thinker SX1278: Works with microcontrollers that support SPI communication.
    • RFM95 916MHz: Also works with microcontrollers that support SPI communication.
  6. Antenna:

    • Ra-02 Ai-Thinker SX1278: Requires the use of an external antenna for proper functioning.
    • RFM95 916MHz: Usually comes with an integrated antenna, eliminating the need for an external antenna.