Control a NodeMCU semi-securely over radio (rename to .ino)

TOTP-DTMF.cpp

/*
Built for NodeMCU ESP32

You'll need 
NTPClient : https://www.arduino.cc/reference/en/libraries/ntpclient/
PhoneDTFM : https://github.com/Adrianotiger/phoneDTMF
TOTP : https://www.arduino.cc/reference/en/libraries/totp-library/

For connecting a baofeng UV-5R I used the kenwood connector and this circuit to remove any bias 
from the baofeng and decouple then used the resistors to center the signal for the NodeMCU.
I then adjusted the volume on the UV-5R until vMax was ~3v when squelch is open to noise.

THIS IS NOT THE BEST CIRCUIT - JUST ONE THAT WORKS FOR THE PROTOTYPE.

BE CAREFUL NOT TO EXCEED 3.3V to the NodeMCU


                    |----------- 3.3v
                    |
                   (R 2K)
                    |
spkr+ ----(C 470nF)------------- D34
                    |
                   (R 2K)
                    |
spkr- ------------------------- gnd

*/

#include <WiFi.h>

#include <TOTP.h>
#include <sha1.h>
#include <NTPClient.h>

#include <driver/adc.h>
#include <PhoneDTMF.h>

#define LED 2


char ssid[] = "";
char password[] = "";

PhoneDTMF dtmf = PhoneDTMF();
WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP);

bool ledStatus = false;
#define RESET_TIME 20
#define INTER_TIME 3

int resetTime = 0;
bool readyDTMF = true;

uint8_t hmacKey[] = {0x4d, 0x79, 0x4c, 0x65, 0x67, 0x6f, 0x44, 0x6f, 0x6f, 0x72}; // for auth apps you'll need to base32 this.
TOTP totp = TOTP(hmacKey, 10);

void setup() {
  adc1_config_width(ADC_WIDTH_BIT_12); // set 12 bit (0-4096)
  adc1_config_channel_atten(ADC1_CHANNEL_6, ADC_ATTEN_DB_11); 
  dtmf.begin(34); 

   pinMode(LED,OUTPUT);


  Serial.begin(9600);
  while (!Serial);

  Serial.println("TOTP demo");
  Serial.println();

  // connect to the WiFi network
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Establishing connection to WiFi...");
  }
  Serial.print("Connected to WiFi with IP: ");
  Serial.println(WiFi.localIP());
  Serial.println();

  // start the NTP client
  timeClient.begin();
  Serial.println("NTP client started");
  Serial.println();
}

String totpCode = String("");
String dtmfCode = String("");

void loop() {
  // put your main code here, to run repeatedly:
  resetTime = resetTime - 1;
  if (resetTime == 0){
     Serial.println("Timed out");
     dtmfCode = "";
     readyDTMF = true;
  }
  uint8_t tones = dtmf.detect();
  char button = dtmf.tone2char(tones);
  if (button > 0) {
    resetTime = RESET_TIME;
    if (readyDTMF == true){
      dtmfCode += button;
      Serial.println(dtmfCode);
      readyDTMF = false;
    }
  }
  if (RESET_TIME - resetTime > INTER_TIME){
    readyDTMF = true;
  }
  timeClient.update();
  String newCode = String(totp.getCode(timeClient.getEpochTime()));
  if (totpCode != newCode) {
    totpCode = String(newCode);
    Serial.print("TOTP code: ");
    Serial.println(newCode);
  }


  if (
    dtmfCode == String(totp.getCode(timeClient.getEpochTime()))  ||
    dtmfCode == String(totp.getCode(timeClient.getEpochTime()-30)) ||
    dtmfCode == String(totp.getCode(timeClient.getEpochTime()-60)) ||
    dtmfCode == String(totp.getCode(timeClient.getEpochTime()-120))
    ) {
     Serial.println("Correct code!");
    if (ledStatus == true){
      ledStatus = false;
      digitalWrite(LED,LOW);
    } else {
      ledStatus = true;
      digitalWrite(LED,HIGH);
    }
    resetTime = 0;
    readyDTMF = true;
    dtmfCode = String();
  }
  
  //Serial.println(analogRead(34));
  delay(100);
}