Example Code for Arduino-LoRa Data Transmission and Reception

Hardware Preparation

• DFR0994 Romeo ESP32-S3 x 2

Software Preparation

• Download Arduino IDE: Click to download Arduino IDE
• Add ESP32 board to Arduino IDE
• Please install the DFRobot_LoRaWAN_ESP32S3 library before use.
• About how to install the library?

Sample Code

Transmitter Side

#include "DFRobot_LoRaRadio.h"

LCD_OnBoard screen;

#define BG_COLOR        COLOR_RGB565_BLACK      // Screen background color
#define TEXT_COLOR      COLOR_RGB565_GREEN      // Screen font color

#define TEXT_FONT       &FreeMono9pt7b          // font
#define TEXT_SIZE       1                       // Screen font size
#define LINE_HEIGHT     18                      // Line height
#define POX_X           0                       // Screen print position X coordinate
#define POX_Y           15                      // Screen print position Y coordinate
#define LINE_1          0                       // Line number
#define LINE_2          1
#define LINE_3          2
#define LINE_4          3

#ifdef REGION_EU868
#define RF_FREQUENCY 868000000  // Hz
#define TX_EIRP 16    // dBm 
#endif
#ifdef REGION_US915
#define RF_FREQUENCY 915000000  // Hz
#define TX_EIRP 22    // dBm 
#endif
#define LORA_SPREADING_FACTOR 7

DFRobot_LoRaRadio radio;
uint8_t buffer[4] = {1, 2, 3, 4};
uint32_t counter = 0;

// Transmission complete callback function
void loraTxDone(void)
{
    printf("-------------------------LoRa Tx done-----------------------------\n");
    screen.fillScreen(BG_COLOR);    
    screen.setTextColor(TEXT_COLOR);
    screen.setFont(TEXT_FONT);
    screen.setTextSize(TEXT_SIZE);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_1);
    screen.printf("Send %dst", counter);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_2);
    screen.printf("done");
}

void setup()
{
    Serial.begin(115200); // Initialize serial communication with a baud rate of 115200
    screen.begin();

    screen.fillScreen(BG_COLOR);    
    screen.setTextColor(TEXT_COLOR);
    screen.setFont(TEXT_FONT);
    screen.setTextSize(TEXT_SIZE);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_1);
    screen.printf("LoRa Send Test");

    delay(5000);   // Open the serial port within 5 seconds after uploading to view full print output
    radio.init();  // Initialize the LoRa node with a default bandwidth of 125 KHz    
    radio.setTxCB(loraTxDone);                  // Set the transmission complete callback function
    radio.setFreq(RF_FREQUENCY);                // Set the communication frequency
    radio.setEIRP(TX_EIRP);                     // Set the Tx Eirp
    radio.setSF(LORA_SPREADING_FACTOR);         // Set the spreading factor
    radio.setBW(BW_125);                        // Set the bandwidth
}

void loop()
{
    printf("statistics: send %d packet\n", ++counter);  // Print the prompt message
    radio.sendData(buffer, /*size=*/4);                 // Send data
    delay(3 * 1000);                                    // Delay 3 seconds before sending next data
}

Receiver Side

#include "DFRobot_LoRaRadio.h"

LCD_OnBoard screen;

#define BG_COLOR        COLOR_RGB565_BLACK      // Screen background color
#define TEXT_COLOR      COLOR_RGB565_GREEN      // Screen font color

#define TEXT_FONT       &FreeMono9pt7b          // font
#define TEXT_SIZE       1                       // Screen font size
#define LINE_HEIGHT     18                      // Line height
#define POX_X           0                       // Screen print position X coordinate
#define POX_Y           15                      // Screen print position Y coordinate
#define LINE_1          0                       // Line number
#define LINE_2          1
#define LINE_3          2
#define LINE_4          3

#ifdef REGION_EU868
#define RF_FREQUENCY 868000000  // Hz
#define TX_EIRP 16    // dBm 
#endif
#ifdef REGION_US915
#define RF_FREQUENCY 915000000  // Hz
#define TX_EIRP 22    // dBm 
#endif
#define LORA_SPREADING_FACTOR 7

DFRobot_LoRaRadio radio;
uint8_t buffer[4] = {1, 2, 3, 4};
uint32_t counter = 0;

void loraRxDone(uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr)
{
    uint8_t i = 0;
    printf("LoRa data received on channel %ld, SF=%d Rssi=%d Snr=%d \nData={",RF_FREQUENCY, LORA_SPREADING_FACTOR, rssi, snr);
    for(; i < size-1; i++){
        printf("0x%02x, ", payload[i]);
    }
    printf("0x%02x}\n\n", payload[i]);

    screen.fillScreen(BG_COLOR);    
    screen.setTextColor(TEXT_COLOR);
    screen.setFont(TEXT_FONT);
    screen.setTextSize(TEXT_SIZE);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_1);
    screen.printf("Recv %dst", ++counter);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_2);
    screen.printf("packet");
}

void loraRxError(void)
{
    printf("LoRaRxError\n");
    screen.fillScreen(BG_COLOR);    
    screen.setTextColor(TEXT_COLOR);
    screen.setFont(TEXT_FONT);
    screen.setTextSize(TEXT_SIZE);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_1);
    screen.printf("LoRaRxError");
}

void setup()
{
    Serial.begin(115200);       // Initialize serial communication with a baud rate of 115200
    screen.begin();

    screen.fillScreen(BG_COLOR);    
    screen.setTextColor(TEXT_COLOR);
    screen.setFont(TEXT_FONT);
    screen.setTextSize(TEXT_SIZE);
    screen.setCursor(POX_X, POX_Y + LINE_HEIGHT * LINE_1);
    screen.printf("LoRa Recv Test");

    delay(5000);                                  // Open the serial port within 5 seconds after uploading to view full print output
    radio.init();                                 // Initialize the LoRa node with a default bandwidth of 125 KHz    
    radio.setRxCB(loraRxDone);                    // Set the receive complete callback function
    radio.setRxErrorCB(loraRxError);              // Set the receive error callback function
    radio.setFreq(RF_FREQUENCY);                  // Set the communication frequency
    radio.setSF(LORA_SPREADING_FACTOR);           // Set the spreading factor
    radio.setBW(BW_125);                          // Set the bandwidth
    radio.startRx();                              // Start receiving
}

void loop()
{
    delay(3000);
}