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"

#define ESP_INTR_FLAG_DEFAULT 0
#define PRG_BUTTON 0


const char* ssid = "<WIFI-SSID>";
const char* password = "<WIFI-PASSWORD>";
String api_base_url = "http://<IP_OF_HR50_API>:5000";
//String api_button_url = api_base_url + "/?cmd=hrtu1";
String api_button_url = api_base_url + "/exec";
String api_status_url = api_base_url + "/status";
int first_row = 0;
int second_row = 24;
int third_row = 48;
int left = 0;
int right = 128;
String cmd_status = "";

SemaphoreHandle_t semaphore = nullptr;

void IRAM_ATTR handler(void* arg) {
  xSemaphoreGiveFromISR(semaphore, NULL);
}

void button_task(void* arg) {
  for (;;) {
    if (xSemaphoreTake(semaphore, portMAX_DELAY) == pdTRUE) {
      cmd_status = send_http_request(api_button_url);
    }
  }
}

String send_http_request(String url) {
    HTTPClient http;
    String response = "";
    http.begin(url.c_str());
    // Send HTTP GET request
    int httpResponseCode = http.GET();
    if (httpResponseCode > 0) {
      response = http.getString();
    }
    else {
      printError("HTTPError: " + (String)httpResponseCode);
    }
    http.end();
    return response;
}


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);

  // Configure PRG button of the Heltec
  semaphore = xSemaphoreCreateBinary();
  // Setup the button GPIO pin
  gpio_pad_select_gpio(PRG_BUTTON );
  // Quite obvious, a button is a input
  gpio_set_direction(GPIO_NUM_0, GPIO_MODE_INPUT);
  // Trigger the interrupt when going from HIGH -> LOW ( == pushing button)
  gpio_set_intr_type(GPIO_NUM_0, GPIO_INTR_NEGEDGE);
  // Associate button_task method as a callback
  xTaskCreate(button_task, "prg_button_task", 4096, NULL, 10, NULL);
  // Install ISR service
  gpio_install_isr_service(ESP_INTR_FLAG_DEFAULT);
  // Add button handler to the ISR
  gpio_isr_handler_add(GPIO_NUM_0, handler, NULL);

}

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


void print_status_screen(JsonObject status_json) {

    if ( status_json != NULL and status_json["PTT"].as<String>() != "ERR") {
      String band = status_json["BND"].as<String>();
      String pep = status_json["PEP"].as<String>();
      String avg = status_json["AVG"].as<String>();
      String swr = status_json["SWR"].as<String>();
      String voltage = status_json["VLT"].as<String>();
      String power = pep + "W/" + avg + "W";
      String ptt = status_json["PTT"].as<String>();
      String temp = status_json["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 );
      if ( cmd_status == "" ) {
        Heltec.display->drawString(left, third_row, voltage );
      } else {
        Heltec.display->drawString(left, third_row, cmd_status );
      }
      // 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();
    }
  
}

void loop() {
  //Check WiFi connection status
  if (WiFi.status() == WL_CONNECTED) {
    String response = send_http_request(api_status_url);
    StaticJsonDocument<200> doc;
    deserializeJson(doc, response);
    JsonObject obj = doc.as<JsonObject>();
    print_status_screen(obj);
 
  }
  else {
    printError("No WiFi!");
  }
}