the-cup/the-cup.ino

/* Pin layout used:
 * -----------------------------------------------------------------------------------------
 *             MFRC522      ESP8266
*             Reader/PCD    Feather Huzzah 
 * Signal      Pin          Pin
 * -----------------------------------------------------------------------------------------
 * SPI SS 1    SDA(SS)      SDA/4
 * SPI SCK     SCK          14 / SCK
 * SPI MOSI    MOSI         13 / MOSI
 * SPI MISO    MISO         12 / MISO
 *
 */

#include <WiFiManager.h> // https://github.com/tzapu/WiFiManager

#include <ESP8266WiFi.h> // https://arduino-esp8266.readthedocs.io/en/latest/esp8266wifi/readme.html
#include <ESP8266HTTPClient.h>
#include <WiFiClientSecureBearSSL.h>

// #include "certs.h"


#include <MFRC522v2.h> // https://github.com/OSSLibraries/Arduino_MFRC522v2
#include <MFRC522DriverSPI.h>
#include <MFRC522DriverPinSimple.h>
#include <MFRC522Debug.h>

#define LED_PIN 15
#define SS_PIN 4

MFRC522DriverPinSimple ss_1_pin(SS_PIN); // Configurable, take an unused pin, only HIGH/LOW required, must be different to SS 2.

MFRC522DriverSPI driver_1{ss_1_pin};

MFRC522 reader{driver_1};   // Create MFRC522 instance.

void read_card(char reader_uid[]);
void send_uid(char reader_uid[]);

void setup() {
  Serial.begin(115200);

  pinMode(LED_PIN, OUTPUT);

  reader.PCD_Init(); // Init each MFRC522 card.
}

void loop() {
  if (reader.PICC_IsNewCardPresent() && reader.PICC_ReadCardSerial()) {
    char reader_uid[32] = "";
    read_card(reader_uid);
    send_uid(reader_uid);
  }
}

void read_card(char reader_uid[]) {
  reader.PICC_HaltA();
  reader.PCD_StopCrypto1();
  byte_to_string(reader.uid.uidByte, 4, reader_uid);
  Serial.println(reader_uid);
  displaySuccess();
}

void send_uid(char reader_uid[]) {
  WiFiManager wm;
  bool res;
  res = wm.autoConnect("KLUK"); // password protected ap

  if(!res) {
    Serial.println("Failed to connect");
    displayError();
    // ESP.restart();
  } 
  else {
    //if you get here you have connected to the WiFi    
    Serial.println("connected...yeey :)");
  }
  auto client = std::make_unique<BearSSL::WiFiClientSecure>();

  client->setInsecure();
  HTTPClient https;
  Serial.print("[HTTPS] begin...\n");
  // configure traged server and url
  https.begin(*client, "https://mood.robiweb.net/rfid_tags");  // HTTP
  https.addHeader("Content-Type", "application/json");

  // start connection and send HTTP header and body
  int httpCode = https.POST("{\"identifier\":\"" + String(reader_uid) + "\"}");
  Serial.print("httpCode: ");
  Serial.println(httpCode);

  if (httpCode > 0) {
    if (httpCode == HTTP_CODE_CREATED) {
    } else {
      Serial.println("Remote error while sending uid");
      displayError();
    }
  } else {
      Serial.print("Remote error while sending uid");
    displayError();
  }

  https.end();
  Serial.print("[HTTPS] ended...\n");
}

void byte_to_string(byte array[], unsigned int len, char buffer[]) {
  for (unsigned int i = 0; i < len; i++)
  {
    byte nib1 = (array[i] >> 4) & 0x0F;
    byte nib2 = (array[i] >> 0) & 0x0F;
    buffer[i*2+0] = nib1  < 0xA ? '0' + nib1  : 'A' + nib1  - 0xA;
    buffer[i*2+1] = nib2  < 0xA ? '0' + nib2  : 'A' + nib2  - 0xA;
  }
  buffer[len*2] = '\0';
}

void displayError() {
  blink(6, 300);
}

void displaySuccess() {
  blink(1, 1000);
}

void blink(unsigned int times, unsigned int duration) {
  for (unsigned int i = 0; i < times; i++)
  {
    digitalWrite(LED_PIN, HIGH);
    delay(duration);
    digitalWrite(LED_PIN, LOW);
    delay(duration);
  }
}