BOM - RFID Attendance System (ESP32)
FULL BUILD TOTAL
₹1,369.00
(7 items)
165 + 263 + 16 + 89 + 380 + 17 + 439
0 / 7 marked
₹0.00 ordered
ROBU.IN CART (5 ITEMS)
₹550.00
(Combined Cart)
0.96" OLED + RDM6300 + Buzzer + PCB + RGB LED
Ordering all 5 Robu items in a single cart saves on courier shipping costs.
ATTENDANCE COMPONENTS
RDM6300 UART
0.96" Blue OLED
Buzzer GPIO
RGB LED
USB Reader (PC enrollment)
1pc each • Prototype stage • Verified Aug 2026 pricing • Complete system
#1
0.96 Inch I2C/IIC 4pin OLED Display Module Blue color
SSD1306, 128x64, I2C 4-pin interface, 0.96", 3.3V/5V, Blue OLED
Robu.in
1 pc
₹165.00
R190597
#2
RDM6300 - EM4100 125KHz RFID Reader Module
125KHz, EM4100, UART interface, ~5cm range, antenna coil included
Robu.in
1 pc
₹263.00
RDM6300
#3
5V Active Electromagnetic Buzzer (Pack of 5)
5V Active, Electromagnetic, 85dB sound output
Robu.in
1 pack (5 pcs)
₹16.00
616166
#4
10 x 15 cm Universal PCB Prototype Board Single-Sided
2.54mm hole pitch, FR4, Single-sided copper dots
Robu.in
1 pc
₹89.00
1031003
#5
ESP32 Development Board CP2102 38-pin
ESP32-WROOM, CP2102, 38-pin, WiFi+BLE, 3.3V logic, Micro USB
Zbotic
1 pc
₹380.00
ESP32-38P
#6
RGB Common Cathode LED - 5mm Tricolor (5pcs)
5mm Transparent, Common Cathode, RGB Tricolor
Robu.in
1 pack (5 pcs)
₹17.00
R183455
#7
xcluma 125KHz USB RFID Reader EM4100 (PC Side)
USB HID, EM4100, For PC/laptop card enrollment, Plug-and-play
Amazon
1 pc
₹439.00
xcluma-125khz
HARDWARE PIN CONNECTIONS • ESP32 38-PIN
ESP32 Pin Connections & Hardware Wiring Guide
Complete schematic reference for interfacing the RDM6300 RFID reader, 0.96" I2C OLED display (SSD1306), active buzzer, and tricolor status LED with the ESP32 microcontroller.
1
RDM6300 RFID Reader (UART)
| RDM6300 Pin | ESP32 Pin | Notes |
|---|---|---|
TX (Pin 1) |
GPIO16 (RX2) |
Serial connection for reading card UID data |
RX (Pin 2) |
Not Connected | Unused for basic card reading |
GND (Pin 3) |
GND |
Common system ground |
VCC (Pin 4) |
5V / VIN |
Requires 5V power supply, not 3.3V |
ANT (Pins 5 & 6) |
Antenna Coil | Connect provided rectangular 125KHz coil to these 2 pins |
Important: The antenna coil must be securely attached for the reader to detect cards. Keep antenna area clear of copper ground pour.
2
0.96" I2C OLED Display (SSD1306 Blue)
| OLED Pin | ESP32 Pin | Notes |
|---|---|---|
GND |
GND |
Common system ground |
VCC |
3.3V |
Standard OLED power (3.3V) |
SCL |
GPIO22 |
I2C Master Clock line |
SDA |
GPIO21 |
I2C Serial Data line (Default Addr 0x3C) |
*Note: If your OLED module has its VCC and GND pins swapped (some models do), ensure you wire them correctly to avoid damaging the module.
3
RGB LED (Common Cathode)
| LED Leg | ESP32 Pin | Notes |
|---|---|---|
Longest Leg (-) |
GND |
Common Cathode ground connection |
Red Leg (R) |
GPIO25 |
Connect in series via a 220Ω resistor (Unknown/Error) |
Green Leg (G) |
GPIO26 |
Connect in series via a 220Ω resistor (Card Accepted OK) |
Blue Leg (B) |
GPIO27 |
Connect in series via a 220Ω resistor (WiFi / Enrolling) |
4
Active Buzzer (5V)
| Buzzer Pin | ESP32 Pin | Notes |
|---|---|---|
Positive (+ / longer leg) |
GPIO32 (or GPIO23) |
Signal control pin (Active HIGH pulse 100ms) |
Negative (- / shorter leg) |
GND |
Common system ground |
PC Enrollment Side (xcluma USB Reader)
The xcluma 125KHz USB RFID Reader connects directly to the school administrator's PC or laptop USB port. It functions as a standard HID keyboard wedge — tapping a card instantly types the 10-digit EM4100 card UID into the student admission / card registration portal without any driver installations.
ATTENDANCE WORKFLOW
01
Card tap → RDM6300 UART → ESP32 parses 10-digit UID
02
0.96" OLED shows Student Name, Timestamp & Status
03
RGB: Green = OK, Red = unknown, Blue = enrolling
04
Buzzer: short beep on success, double beep on error
05
WiFi HTTPS POST to Divine Academix server & FCM parent alert
Power Consumption Budget
ESP32 active average
120mA
RDM6300 RF reader
50mA
0.96" OLED Display
20mA
Buzzer peak pulse
30mA
Total Estimated Current
~220mA @ 5V (Standard 1A / 2A adapter is optimal)
PROTOTYPE BOARD (PCB) NOTES
- Use the 10x15cm single-sided FR4 proto board with 2.54mm hole pitch.
- Place ESP32 in the center; keep the RDM6300 antenna coil area clear of solid copper ground pours.
- Route buzzer signal wires away from high-speed I2C SDA/SCL lines to prevent electromagnetic interference.
- Add a 100nF ceramic decoupling capacitor across ESP32 3.3V and GND power rails for noise immunity.