LoRa 32 WIFI Receiver

LoRa_receiver.ino

#include <SPI.h>
#include <LoRa.h>
#include <Wire.h>  //responsible for i2c communication
#include "SSD1306Wire.h"
#define SS      18
#define RST     14
#define DI0     26

SSD1306Wire display(0x3c, 4, 15);

void setup() {
  //battery
  pinMode(32, INPUT);
  //set pin as output
  pinMode(16,OUTPUT); //OLED RST
  pinMode(25,OUTPUT);
  digitalWrite(16, LOW); //resets OLED
  delay(50); 
  digitalWrite(16, HIGH); //while OLED is on, GPIO might be HIGH
  //Starts LoRa's display
  display.init();
  display.flipScreenVertically(); 
  display.setFont(ArialMT_Plain_10);

  SPI.begin(5, 19, 27, 18);
  LoRa.setPins(SS, RST, DI0);
  
  Serial.begin(4800);
  while (!Serial);
  //433E6, 868E6, 915E6
  if (!LoRa.begin(433E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }  
  //clear LoRa's display
  display.clear();
  display.drawString(0, 0, "LoRa Initial success!");
  display.display();//showcase the string on LoRa's display
}
void loop() {
  String packet="", rssi;
  float bat=analogRead(32);//reads battery value
  int packetSize = LoRa.parsePacket();
  if(packetSize){
    //while there's something on LoRa's packet
    while (LoRa.available()) 
      packet += (char)LoRa.read();//reads and save the string
    //sends string to Serial
    for(int i=0;i<packet.length();i++)
      Serial.write(packet[i]);
        
    rssi = (String)LoRa.packetRssi();
    //clear LoRa's display
    display.clear();
    display.drawString(0, 0, "GSE - RECEIVER");
    display.drawString(0, 10, "RSSI:");
    display.drawString(50, 10, rssi);
    display.drawString(0, 20, "Packet:");
    display.drawString(50, 20, packet);
    display.drawString(0, 30, "Battery:");
    display.drawString(50, 30, (String)bat);
    display.display();//showcase the string on LoRa's display
  }
  //pause for 1 second for each byte
  delay(1000*packet.length());
  //clear other packets
  LoRa.flush();
}