Based on the NXP LPC54101 E-Lock solution that can be directly mass-produced, it has combined the functions of fingerprint, card swiping, and password.

Aiming at the smart door lock market, a mass-produced E-Lock solution based on NXP LPC54101 was launched. This solution combines fingerprint, password, card swiping functions, and reserves UART, which can easily expand other functions such as BLE, ZigBee, NB-IoT, and face recognition. LPC54101 is equipped with SPI, I2C, UART and other serial interfaces to meet the needs of E-Lock applications. According to the actual market demand for E-Lock fingerprints, passwords, and card swiping, World Peace Group has optimized the hardware schematics, PCB and software to meet mass production needs. Customers can make mass production with slight modifications according to World Peace Group’s plans. 

1.1 Hardware design description:

1. Master

It uses NXP MCU LPC54101, which is a mainstream 32-bit microcontroller with ARM Cortex-M4 core, large-capacity Flash & RAM. Its basic parameters are as follows:

• ARM Cortex-M4 processor, the operating frequency can be up to 100 MHz, using the same clock as Cortex-M4.
• Floating Point Unit (FPU) and Memory Protection Unit (MPU).
• Flash in-application programming (ISP) and in-system programming (IAP).
• DMA controller, with 22 channels and 20 programmable triggers, can access all memories and peripherals that support DMA.
• A 12-bit 12-channel analog-to-digital converter (ADC) that supports 5.0 MSPS. The ADC supports two independent conversion sequences.
• Adopt 3.288 mm x 3.288 mm WLCSP49 package and LQFP64 package.
• Up to 512 kB of on-chip flash programmable memory, with flash accelerator and 256-byte page erasing and writing functions.
• A total of 104KB of SRAM is included, including 96 kB of continuous main SRAM and an additional 8 kB of SRAM.
• Low power consumption, high cost performance
• The price of the chip has an advantage over similar products.

The functional block diagram of the master MCU is shown in the figure below:

2. Fingerprint Sensor

The fingerprint Sensor used in the solution is Bertel’s BF82160. BF82160 is a 160*160 fingerprint sensor. It can be connected to LPC54101 via SPI interface. As shown in the figure below, the encapsulated fingerprint Sensor is inside the black box.

1. Touch the button

The touch button chip used in the solution is TMS12 from ADS. Its characteristics are as follows:

• 12-channel capacitive sensor, automatic sensitivity calibration
• Selectable output operation (single-mode/multi-mode)
• I2C serial interface
• Independently adjustable 8-step sensitivity
• Typical current value 60uA
• Sleep current value 10uA
• QFN32 small package

4. NFC Swipe

The NFC chip used in the plan is NXP's MFRC630. Its characteristics are as follows:

• The communication distance with ISO 14443 A/MIFARE Classic in the reader mode is up to 120mm, depending on the antenna length and tuning.
• Support MIFARE Classic encryption;
• Supported host interface:

-10Mbit/s SPI interface

-I2C interface, the speed of fast mode is 400kbit/s, the speed of high-speed mode is 3400kbit/s

-Serial UART, the transmission rate is up to 1228.8kbit/s, the frame depends on the RS232 interface, and the voltage level depends on the pin voltage provided.

• 512-byte transmit and receive FIFO buffer;
• Use mutually independent multiple sets of power supplies to avoid mutual interference between modules and improve working stability. 12-channel capacitive sensor, automatic sensitivity calibration.

2. Software Architecture

The LPC54101 E-Lock software framework includes: driver layer, middle layer, and application layer. Our state machine framework is used in the application layer. The driver layer and the middle module layer are ultimately prepared for the application layer. The purpose of the design is to achieve high cohesion and low coupling, and to distinguish each module clearly. When replacing the MCU, sometimes only the driver layer needs to be replaced. Reduce development time, improve development efficiency, and increase maintainability.

► Scenario application diagram

► Scenario application diagram

► Scheme block diagram

► Schematic

► PCB

► PCB

► Core technical advantages

1. Mass production: mature software and hardware system, can be mass produced after UI adjustment
2. Single chip: the fingerprint algorithm is integrated in the main control of the door lock, achieving the ultimate cost performance
3. Scalability: extended 3D face recognition function has been realized
4. Openness: open technical data, WPI technical support
5. High quality: using NXP MCU+NFC chip, excellent quality

► Solution specifications

1. MCU built-in fingerprint algorithm, saving cost
2. Multi-function door lock, support fingerprint, NFC, password and other methods to unlock
3. Support single/combination unlock mode, normally open mode
4. Support tamper-proof alarm, emergency charging, user buttons, OLED display
5. Support power monitoring, voice broadcast, Chinese and English switching