hr50-remote-display/hr50-remote-display.ino

#include <WiFi.h>
#include <HTTPClient.h>
#include "Arduino.h"
#include "heltec.h"
#include <ArduinoJson.h>
#include "hr50_fonts.h"

const char* ssid = "<WIFI-SSID>";
const char* password = "<WIFI-PASSWORD>";
String api_url = "http://<IP_OF_HR50_API>:5000/status";


int first_row = 0;
int second_row = 24;
int third_row = 48;
int left = 0;
int right = 128;

void setup() {
  Heltec.begin(true /*DisplayEnable Enable*/, false /*LoRa Disable*/, false /*Serial Enable*/);
  Heltec.display->flipScreenVertically();
  Heltec.display->setFont(DialogInput_plain_16);
  WiFi.begin(ssid, password);
  delay(4000);
}

void printError(String err) {
  Heltec.display->clear();
  Heltec.display->setTextAlignment(TEXT_ALIGN_LEFT);
  Heltec.display->drawString(left, second_row, err );
  Heltec.display->display();
}

void loop() {
  //Check WiFi connection status
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String payload = "";
    http.begin(api_url.c_str());

    // Send HTTP GET request
    int httpResponseCode = http.GET();

    if (httpResponseCode > 0) {
      payload = http.getString();
    }
    else {
      printError("HTTPError: " + (String)httpResponseCode);
    }
    // Free resources
    http.end();

    StaticJsonDocument<200> doc;
    deserializeJson(doc, payload);
    JsonObject obj = doc.as<JsonObject>();

    if ( obj != NULL and obj["PTT"].as<String>() != "ERR") {
      String band = obj["BND"].as<String>();
      String pep = obj["PEP"].as<String>();
      String avg = obj["AVG"].as<String>();
      String swr = obj["SWR"].as<String>();
      String voltage = obj["VLT"].as<String>();
      String power = pep + "W/" + avg + "W";
      String ptt = obj["PTT"].as<String>();
      String temp = obj["TMP"].as<String>();

      // clear the display
      Heltec.display->clear();
      // print left column
      Heltec.display->setTextAlignment(TEXT_ALIGN_LEFT);
      Heltec.display->drawString(left, first_row, band );
      Heltec.display->drawString(left, second_row, power );
      Heltec.display->drawString(left, third_row, voltage );
      // print right column
      Heltec.display->setTextAlignment(TEXT_ALIGN_RIGHT);
      Heltec.display->drawString(right, first_row, swr );
      Heltec.display->drawString(right, second_row, ptt );
      Heltec.display->drawString(right, third_row, temp );
      Heltec.display->display();
    }
    else
    {
      // print a "(!)" centered in the third row
      // this happens when the TRX/PA is transmitting
      // or otherwise an empty response was send by the API
      Heltec.display->setTextAlignment(TEXT_ALIGN_LEFT);
      Heltec.display->drawString(58, third_row, "(!)" );
      Heltec.display->display();
    }
  }
  else {
    printError("No WiFi!");
  }
}