Receiver stops receiving data randomly

[joanila]

I have 2 ESP32 communicating through LoRa. Communication works perfectly till after some time (typically a few hours) the receiver stops receiving data. After reseting the receiver or turning it off/on the power supply several times, data reception is resumed. Any idea about the origin of this erratical lock-down ? Here you have the sender and receiver code:

SENDER:

`//======================================================================//

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

//======================================================================//

#define PIN_LORA_COPI 23
#define PIN_LORA_CIPO 19
#define PIN_LORA_SCK 18
#define PIN_LORA_CS 5
#define PIN_LORA_RST 2
#define PIN_LORA_DIO0 4

#define LORA_FREQUENCY 433E6

//======================================================================//

int counter = 0;

//======================================================================//

void setup() {
Serial.begin (115200);
while (!Serial);
delay (1500);
Serial.println ("LoRa Sender");

LoRa.setPins (PIN_LORA_CS, PIN_LORA_RST, PIN_LORA_DIO0);
LoRa.setSPIFrequency (20000000);
LoRa.setTxPower (20);

if (!LoRa.begin (LORA_FREQUENCY)) {
Serial.println ("Starting LoRa failed!");
while (1);
}
else {
Serial.print ("LoRa initialized with frequency ");
Serial.println (LORA_FREQUENCY);
}
LoRa.setSyncWord(0xF3); // ranges from 0-0xFF, default 0x34, see API docs
}

//======================================================================//

void loop() {

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

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

delay (1000);

}`

RECEIVER:

`//======================================================================//

#include <SPI.h>
#include <LoRa.h>
#include <LiquidCrystal_I2C.h>
// set the LCD number of columns and rows
int lcdColumns = 16;
int lcdRows = 2;

// set LCD address, number of columns and rows
// if you don't know your display address, run an I2C scanner sketch
LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows);
//======================================================================//

#define PIN_LORA_COPI 23
#define PIN_LORA_CIPO 19
#define PIN_LORA_SCK 18
#define PIN_LORA_CS 5
#define PIN_LORA_RST 2
#define PIN_LORA_DIO0 4

#define LORA_FREQUENCY 433E6

//======================================================================//

void setup() {
Serial.begin (115200);
while (!Serial);
delay (1500);

lcd.init(); // initialize lcd
lcd.backlight(); // turn on LCD backlight

Serial.println ("LoRa Receiver");
LoRa.setPins (PIN_LORA_CS, PIN_LORA_RST, PIN_LORA_DIO0);
LoRa.setSPIFrequency (20000000);

if (!LoRa.begin (LORA_FREQUENCY)) {
Serial.println ("Starting LoRa failed!");
while (1);
}
else {
Serial.print ("LoRa initialized with frequency ");
Serial.println (LORA_FREQUENCY);
}
LoRa.setSyncWord(0xF3);
}

//======================================================================//

void loop() {

int counter,rssi,snr;

int packetSize = LoRa.parsePacket(); // packet received ?
if (packetSize) {

// read packet
/*
while (LoRa.available()) {
  Serial.print ((char) LoRa.read());
}
Serial.println();
*/

counter = LoRa.parseInt();  // get payload (single int)

Serial.print("Received Message nr. ");
Serial.print(counter);  // print payload, and
Serial.print (" with RSSI ");     // print RSSI of packet
rssi=LoRa.packetRssi();
Serial.println (rssi);
snr=LoRa.packetSnr();


lcd.clear(); 


lcd.setCursor(0, 0);   // ... second row, column 0
lcd.print("RSSI");
lcd.setCursor(5, 0);  // ... second row, column 7
lcd.print(rssi);
lcd.setCursor(10, 0);  // set cursor to first column, first row
lcd.print("#");
lcd.setCursor(11, 0);   // ... first row, column 10
lcd.print(counter);
lcd.setCursor(0,1);
lcd.print("SNR");
lcd.setCursor(5, 1);   // ... second row, column 0
lcd.print(snr);

}
}
`