ESP-1ch-Gateway/libraries/Heltec_ESP32_Dev-Boards/examples/LoRa/LoRaSender/LoRaSender.ino

/* 
  Basic test program, send date at the BAND you seted.
  
  by Aaron.Lee from HelTec AutoMation, ChengDu, China
  成都惠利特自动化科技有限公司
  www.heltec.cn
  
  this project also realess in GitHub:
  https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series
*/
#include "heltec.h"
#define BAND    433E6  //you can set band here directly,e.g. 868E6,915E6

int counter = 0;

void setup() {
  
  //WIFI Kit series V1 not support Vext control
  Heltec.begin(true /*DisplayEnable Enable*/, true /*Heltec.LoRa Disable*/, true /*Serial Enable*/, true /*PABOOST Enable*/, BAND /*long BAND*/);

  
}

void loop() {
  Serial.print("Sending packet: ");
  Serial.println(counter);
  // send packet
  LoRa.beginPacket();
  LoRa.print("hello ");
  LoRa.print(counter);
  LoRa.endPacket();
  
  counter++;
  digitalWrite(25, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(25, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}