The Contactless Car Unlocking System allows a user to unlock a car with a specific NFC card instead of using a physical key. NFC-compatible bank cards, student ID cards, etc. may be scanned at the sensor location to remotely press the unlock button inside of the car using a 5V relay. The system is powered by the car’s battery which is stepped down to a low enough voltage with a voltage regulator. All components are interfaced through a custom printed circuit board (PCB) and housed in a 3D printed enclosure.

Components:

• MBED LPC1768
• uLCD-144-G2 128 by 128 Smart Color LCD
• 5V relay
• PN532 NFC reader
• Custom PCB
• 3D printed housing

A custom 4-layer PCB includes power management, the microcontroller, and peripherals.

• 4-layer PCB
• LTM8053 Switching Regulator (integrated inductor, 6A max output current)
• Dual LP38692 LDO Voltage Regulator (1A output, separate for servo and microcontroller power)

The program runs in three separate threads to manage the NFC scanner and uLCD at the same time.

• Main Thread - Initializes uLCD and NFC scanner threads.
• uLCD Thread - Displays invalid card and card accepted messages according to card scanned.
• NFC Reader - Asks scanner for ID of card scanned, checks it against a known ID, and turns on relay accordingly.

More info including PCB design may be found HERE