Usage Example for ESP32-LoRa Wireless Transmission

Hardware Preparation

• FireBeetle ESP32 IoT Microcontroller(SKU: DFR0478) ×2
• LoRa Radio 915MHz - FireBeetle Covers(SKU: TEL0122) ×2
• USB Cable ×2
• Dupont Wires

Software Preparation

• Download Arduino IDE: Click to download Arduino IDE.
• Download and install the DFRobot_Lora
• For Arduino IDE V1.8.19 (or earlier), install the library manually: How to Add a Library？

Wiring Diagram

Connection:

• Joint ESP32 board and LoRa module together.
• Connect ESP32 board to PC via USB line.

Other Preparation Work

Pin Connection Configuration Guide

Supplementary Notes:

• NSSPin/NRESETPin: Function input parameters for specifying custom CS/RESET pins.
• NSS_PIN/RESET_PIN: Default macro definitions corresponding to the default pins D4/D2.

Sample Code

Download the master program and the slave program to two ESP32 board respectively.

The Slave program code: LoRa module receives data, prints data/RSSI and toggles onboard LED.

/*!
 * @file receiverTest.ino
 * @brief DFRobot's received data
 * @n [Get the module here]
 * @n This example is receive.
 * @n [Connection and Diagram]
 *
 * @copyright   [DFRobot](https://www.dfrobot.com), 2016
 * @copyright   GNU Lesser General Public License
 *
 * @author [yangyang]
 * @version  V1.0
 * @date  2017-04-10
 */

#include <DFRobot_LoRa.h>

DFRobot_LoRa lora;

uint8_t len;
uint8_t rxBuf[32];

void setup()
{
    Serial.begin(115200);

    pinMode(LED_BUILTIN, OUTPUT);
    Serial.println("Receiver Test");

    while(!lora.init()) {
        Serial.println("Starting LoRa failed!");
        delay(100);
    }

    lora.rxInit();
}
void loop()
{
    if(lora.waitIrq()) {   // wait for RXDONE interrupt
        lora.clearIRQFlags();
        len = lora.receivePackage(rxBuf);  // receive data
        Serial.write(rxBuf, len);
        Serial.println();
        lora.rxInit();    // wait for packet from master

        // print RSSI of packet
        Serial.print("with RSSI ");
        Serial.println(lora.readRSSI());

        static uint8_t i;
        i = ~i;
        digitalWrite(LED_BUILTIN, i);
    }
}

The Master program code: LoRa module sends specified data cyclically, counts and prints send times.

/*!
 * @file sendTest.ino
 * @brief DFRobot's send data
 * @n [Get the module here]
 * @n This example is send.
 * @n [Connection and Diagram]
 *
 * @copyright   [DFRobot](https://www.dfrobot.com), 2016
 * @copyright   GNU Lesser General Public License
 *
 * @author [yangyang]
 * @version  V1.0
 * @date  2017-04-10
 */

#include <DFRobot_LoRa.h>

DFRobot_LoRa lora;

uint8_t counter = 0;
uint8_t sendBuf[] = "HelloWorld!";

/* The default pin:
 *      SS:D4
 *      RST:D2 (If you are using the FireBeetle Board-ESP8266 motherboard controller, the RST defaults to D3)
 */

void setup()
{
    Serial.begin(115200);

    while(!lora.init()) {
        Serial.println("Starting LoRa failed!");
        delay(100);
    }
}
void loop()
{
    Serial.print("Sending packet: ");
    Serial.println(counter);

    // send packet
    lora.sendPackage(sendBuf, 11); // sending data
    lora.idle();    // turn to standby mode

    counter++;
#if 0
    if(counter%10 == 0) {
        lora.sleep();
        delay (5000);// sleep 5 seconds
    }
#endif

    delay(500);
}

Results

Two ESP32 motherboards successfully communicate and receive data.