A hardware design project for a secure elevator access system using multi-level authentication — RFID, fingerprint, and capacitive keypad — controlled by an STM32G070CBT6 microcontroller. The deliverable is a complete schematic and double-layer PCB design created in EasyEDA.
The system restricts elevator access to authenticated users only. Authentication follows a layered flow: RFID card scan → optional fingerprint or keypad verification → floor selection via touch keypad. Visual feedback is provided through a 7-segment display and 16 LEDs controlled via a shift register to minimize GPIO usage. A DC-DC converter handles the 24V to 5V step-down for the entire system.
- Multi-level authentication: RFID + fingerprint + capacitive keypad
- 16-channel touch keypad (TTP229) for floor selection
- 7-segment display for current/selected floor indication
- 74HC595 shift register to drive 16 LEDs with only 3 MCU pins
- W25Q128 serial flash for storing user credentials and access logs
- MC34063A DC-DC converter stepping 24V → 5V
- Double-layer PCB with modular section layout for clean signal routing
| Component | Part Number | Purpose |
|---|---|---|
| Microcontroller | STM32G070CBT6 | Core processing and peripheral control |
| RFID Reader | RC522 | 13.56 MHz card scanning (ISO 14443A) |
| Fingerprint Sensor | ZW101 | Optical fingerprint capture and matching |
| Touch Keypad | TTP229 | 16-key capacitive input for floor selection |
| Shift Register | 74HC595 | Expand GPIO — drive 16 LEDs with 3 pins |
| Serial Flash | W25Q128 | 16MB non-volatile storage for user data |
| 7-Segment Display | — | Floor number display |
| DC-DC Converter | MC34063A | Step down 24V → regulated 5V |
- ARM Cortex-M0+, up to 64 MHz
- 128 KB Flash, 36 KB SRAM
- 2× I²C, 2× SPI, 4× USART
- 12-bit ADC, PWM timers
- 2.0V to 3.6V supply voltage
- Operating frequency: 13.56 MHz
- Tag memory: 1 KB
- Interface: SPI
- Compatible with ISO 14443A tags (read & write)
- Interface: UART
- Built-in optical sensor and matching processor
- Stores fingerprint templates internally
- Capacity: 128 Mbit (16 MB)
- Interface: SPI (up to 104 MHz)
- 100,000 erase cycles per sector, >20 years data retention
User Approaches Elevator
│
▼
RFID Card Scan (RC522)
│
├─ Not Recognized → Access Denied
│
└─ Recognized
│
▼
Fingerprint / Keypad Verification (ZW101 / TTP229)
│
├─ Failed → Access Denied
│
└─ Verified
│
▼
Floor Selection via Touch Keypad
│
▼
Relay Triggered → Elevator Moves
elevator-security-control-system/
│
├── hardware/
│ ├── schematic.pdf # Full schematic (EasyEDA export)
│ ├── pcb_design.pdf # PCB layout (EasyEDA export)
│ └── gerber/ # Gerber files ready for manufacturing
│ └── *.gbr
│
├── docs/
│ ├── pcb_front_back.png # 2D front and back PCB render
│ └── bom.csv # Bill of Materials
│
├── .gitignore
└── README.md
Designed in EasyEDA as a double-layer board following this process:
- Schematic Creation — All components and sub-circuits mapped out in four sections: Shift Register Circuit, Touch Button Circuit, Microcontroller Circuit, Voltage Converter Circuit, and Serial Flash Memory
- Footprint Assignment — SMD packages selected to minimize board area
- Routing — Short direct traces, decoupling capacitors placed close to IC power pins to reduce voltage ripple
- Component Grouping — Each functional block assigned its own PCB region to simplify debugging and testing
- DRC & ERC Check — Design verified for electrical and layout errors
- Gerber Export — Files finalized and ready for manufacturing
- EasyEDA — Schematic and PCB design
- STM32G070CBT6 Datasheet
- MFRC522 Datasheet
- W25Q128 Datasheet
- Firmware development for STM32 to implement the full authentication logic
- Cloud connectivity for remote access control and audit logging
- Real-time elevator status reporting via wireless interface
Arya Sureshbhai Patel