Tapping the 'Tmoney' or 'Ezl (as known as CashBee)' card to the NFC module displays the remaining balance on the OLED screen, offers the most intuitive way to check the balance on the card.
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Added README.md
Comments have added to each function in the source code.
Displays more information (Serial number, Date issued, Card type) on the OLED Screen.
Supports beep sound using the piezo buzzer.
Supports notification lights using the dedicated LED on the ESP8266 chipset.
Displays error messages about undetectable cards on the OLED display.
Added various beep sounds depending on different situations.
- Tapping the card to the NFC module displays the remaining balance and other information retrieved from it on the OLED screen.
- T-Money Cards
- EZL Card (Cash-Bee) Cards
- RailPlus Cards
- Hanpay Cards
- 1 x Micro-USB
- IEEE 802.11 b/g/n Wi-Fi technology.
- Not required to use the Wi-Fi capability for this project.
- MIFARE 1k, 4k, Ultra light, and DESFIRE cards, ISO/IEC 14443-4 cards such as CD97BX, CD light, DESFIRE, P5CN072 (SMX), INNOVISION Jewel cards such as IRT5001 card, FELICA cards such as RCS_860 and RCS_854
- Built-in PCB Antenna, with 5 cm to 7 cm communication distance.
- Host communication : SPI Interface
- Operating temperature : -30ºC to +85ºC
- Contactless communication at 13.56MHz
- Up to 9.5 hours (9 hours and 30 minutes) of typical device usage.
- Testing consisted of full-time active use until complete battery discharge.
- Wi-Fi was not connected to any network.
- Dedicated LED indicators on the ESP8266 chipset have been disabled until the battery is completely exhausted.
- Battery life may vary significantly with settings, usage and other factors.
- NodeMCU ESP8266-12E
- Soldering required.
- Connection Type : SPI
- D4 : SS of PN532
- D5 : TX of PN532
- D6 : MISO of PN532
- D7 : MOSI of PN532
- GND : GND of PN532
- VIN : VCC of PN532
- Soldering required
- D2 : Data, D1 : Clock
- USB Port : Power
- Micro-USB : Charging Port
- Dimension : 63.3 mm (W) × 90.7 mm (D) × 13.0 mm (H)
- Input : DC-5V / 2A (Micro 5-pin)
- Output : DC-5V / 2A (2 USB ports)
- Capacity : 5,000 mAh
- Tapping the 'Tmoney' or 'Ezl (as known as CashBee)' card to the NFC module displays the remaining balance on the OLED screen.
The 'Tmoney' or 'Ezl' card is a rechargeable smart card that can be used to pay public transit fares in the Seoul-Gyeonggi areas as well in other cities around Korea (bus, underground/metro, taxi) as well as purchases in designated areas. The 'Tmoney' card can be used to pay subway and bus and taxi travel.
This is a library for the Adafruit-PN532 NFC / RFID breakout boards This library works with the Adafruit NFC breakout. https://github.com/adafruit/Adafruit-PN532
This is a driver for SSD1306 128x64, 128x32, 64x48 and 64x32 OLED displays running on the Arduino/ESP8266 & ESP32 and mbed-os platforms. Can be used with either the I2C or SPI version of the display. https://www.github.com/ThingPulse/esp8266-oled-ssd1306
SSD1306 display(0x3c, D2, D1); // Object declaration for OLED screen display.
Adafruit_PN532 nfc(PN532_SS); // Object declaration for NFC capabilities.
char card_id[16 + 1] = ""; // Card No. (16-bytes)
char date_issued[8 + 1] = ""; // Date issued. (8-bytes)
char card_issuer = 0x00; // Card issuer
char card_type = 0x00; // Card typevoid setup() {
// Initialize Serial Communication
Serial.begin(115200);
delay(50);
// Initialize LED pin
pinMode(LED_BUILTIN, OUTPUT);
digitalWrite(LED_BUILTIN, HIGH);
// Initialize NFC module
nfc.begin();
uint32_t versiondata = nfc.getFirmwareVersion();
if (!versiondata) {
Serial.print("Didn't find PN53x board");
while (1);
}
// Display NFC module details on console
Serial.print("Found chip PN5"); Serial.println((versiondata >> 24) & 0xFF, HEX);
Serial.print("Firmware ver. "); Serial.print((versiondata >> 16) & 0xFF, DEC);
Serial.print('.'); Serial.println((versiondata >> 8) & 0xFF, DEC);
// Initialize OLED display
display.init();
display.flipScreenVertically();
display.display();
delay(2000);
// Display initial message
display.clear();
display.setFont(ArialMT_Plain_10);
display.drawString(0, 0, "T-Money Balance Checker");
display.drawString(1, 17, "To check the balance,");
display.drawString(1, 29, "please tag your prepaid");
display.drawString(1, 41, "T-Money card to this device.");
display.display();
}void loop() {
uint8_t success;
uint8_t responseLength = 64;
success = nfc.inListPassiveTarget();
if (success) {
Serial.println("Found something!");
// Read card information
uint8_t cardInfo[responseLength];
uint8_t selectApdu[] = { 0x00, 0xA4, 0x00, 0x00, 0x02, 0x42, 0x00 };
success = nfc.inDataExchange(selectApdu, sizeof(selectApdu), cardInfo, &responseLength);
if (success) {
Serial.print("responseLength : "); Serial.println(responseLength);
nfc.PrintHexChar(cardInfo, responseLength);
if (responseLength >= 24) {
CharToHex(cardInfo + 13, card_id, 3); // Card No.
CharToHex(cardInfo + 21, date_issued, 3); // Date issued
card_issuer = cardInfo[7]; // Card issuer
card_type = cardInfo[29]; // Card type
Serial.print("card number : "); nfc.PrintHexChar(cardInfo + 8, 8);
Serial.print("date issued : "); nfc.PrintHexChar(cardInfo + 21, 4);
Serial.print("card issuer : "); Serial.println(issuer_corps((int)card_issuer));
Serial.print("card type : "); Serial.println(user_type((int)card_type));
}
} else {
Serial.print("Not recognized.");
display.clear();
display.display();
display.drawString(0, 0, ": ( Unrecognized Card!");
display.drawString(0, 17, "Please tag your prepaid");
display.drawString(0, 29, "T-Money card to this");
display.drawString(0, 41, "device.");
display.display();
beep_error();
delay(1000);
return;
}
// Balance inquiry
uint8_t balance[responseLength];
uint8_t balanceApdu[] = { 0x90, 0x4C, 0x00, 0x00, 0x04 };
success = nfc.inDataExchange(balanceApdu, sizeof(balanceApdu), balance, &responseLength);
if (success) {
Serial.print("responseLength : "); Serial.println(responseLength);
nfc.PrintHexChar(balance, responseLength);
if (responseLength >= 4) {
char fpsbuf[32] = ""; // Convert numbers to strings for display
uint32_t credit = balance[0] * 256 * 256 * 256 + balance[1] * 256 * 256 + balance[2] * 256 + balance[3];
display.clear();
memset(card_id + 0, 'x', 2); // Extra security
display.drawString(0, 0, card_id);
display.drawString(39, 0, date_issued);
display.drawString(78, 0, user_type((int)card_type));
dtostrf((float)credit, 10, 0, fpsbuf);
display.setFont(ArialMT_Plain_24);
display.drawString(0, 11, fpsbuf);
display.setFont(ArialMT_Plain_10);
if (credit < 1700) {
display.drawString(0, 32, "The balance on your");
display.drawString(0, 42, "card is critically low.");
display.drawString(0, 52, "Please recharge it NOW.");
beep_creditLow();
} else if (credit < 4000) {
display.drawString(0, 32, "You have less than");
display.drawString(0, 42, "4,000 KRW on your card.");
display.drawString(0, 52, "Please recharge it ASAP.");
beep();
} else {
display.drawString(0, 32, "Have a great day and");
display.drawString(0, 42, "stay safe while travelling.");
display.drawString(0, 52, "* ^ - ^ *");
beep();
}
display.display();
beep();
Serial.print("Balance left on this card : "); Serial.println(credit);
Serial.println("");
delay(3000);
}
}
} else {
display.clear();
display.setFont(ArialMT_Plain_10);
display.drawString(0, 0, "T-Money Balance Checker");
display.drawString(1, 17, "To check the balance,");
display.drawString(1, 29, "please tag your prepaid");
display.drawString(1, 41, "T-Money card to this device.");
nfc.SAMConfig();
display.display();
}
delay(100);
}void CharToHex(uint8_t *ch, char* szHex, int len) {
unsigned char saucHex[] = "0123456789ABCDEF";
for (int i = 0; i < len; i++) {
szHex[i * 2 + 0] = saucHex[ch[i] >> 4];
szHex[i * 2 + 1] = saucHex[ch[i] & 0xF];
}
}char* issuer_corps(int idx) {
switch (idx) {
case 1: return "KFTC"; // Korea Financial Telecomunications & Clearings Institute
case 2: return "A-Cash";
case 3: return "Mybi";
case 5: return "V-Cash";
case 6: return "Mondex Korea";
case 7: return "Korea Expressway Corp.";
case 8: return "T-Money";
case 9: return "Korail"; // The Korea Railroad CorporationCopyright ⓒ HappyBono 2021 - 2025. All rights Reserved.
This project is licensed under the MIT License. See the LICENSE file for details.
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Hyunwoo Nam, Byunggeun Jang, Youngwook Park, 2012, A Design of Card Processing Method based on Script File for AFC Terminal, KoreaScience, Journal of The Korea Society of Computer and Information (JKSCI), viewed 5 January 2021, https://www.koreascience.or.kr/article/CFKO201202135240043.pdf.
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Chaeum Co., Ltd. (주식회사 채움씨앤아이), 2014, A study on adding the function of a national compatible transportation card to the Book Yieum Pass (Public Library Cards), Ministry of Culture, Sports and Tourism, 공공누리 자료집, viewed 7 January 2021, http://www.codil.or.kr/filebank/original/RK/OTKCRK170036/OTKCRK170036.pdf.