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Base on the SoC nRF24LE1 that include radio frequency control chip and 8051f by Nordic company.
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The Design of Electronic License Plate Recognition Terminal System based on
nRF24LE12012 Fifth International Symposium on Computational Intelligence and Design
Wei Chen, Jianding Yu, Xiangjun Liu
Emp, CHEN
Ajenda
• Introduction
• System structure
• Hardware design– Reader module
– Electronic tag
• Software design– Reader module
– Electronic tag
• Conclusion
Introduction
Introduction
• The limited Land resources and economy is a big challenge for the urban road construction.
• ITS(Intelligent Transportation Systems)
• The RFID technology has advantage in long-range identification, carrying more information, reading data rapidly and wide application
System structure
System structure
• The system consists of reader, electronic license plate(E-Plate) and host computer management system.
• When the vehicle, which has been installed electronic license plate, enters the range of the reader.
Analysis and StoreCommunication
Hardware design
Hardware design
• Reader module–ARM chip, RF(Radio frequency), Control
circuit.
• E-plate module–Wireless RF application circuit.
–Base on nRF24LE1
– Some peripheral
Hardware design
• Reader Module
–LM3S8962
• Cortex M3、50MHz、36 Interrupts、Cheap(?)
• Main
–Process、Memory、Power conversion
• Extended
–RF(Communication by I2C)、JTAG、LCD+Touch、LED…
Hardware design
• RF circuit - receive the information from E-plate and send to the processor through the mode of I2C.
• Processor deals with the received information and sends to the PC
• LCD&TS - human-computer interaction
Hardware design
Program
Date
To PC To E-plate
Hardware design
• E-Plate (nRF24LE1)– 8051F + nRF24l01P
– The stability and reliability of the RF system is increased and the cost is reduced
– ISM Frequency band from 2.4GHz to 2.5GHz
– Maximum transmission rate 2Mbit/s
– Distance 100m (Without sleep)
Software design
Software design
• Reader
– The real-time operating system FreeRTOS is used for the reader control
– The TCP / IP protocol stack has been portedto the FreeRTOS
Software designStep1: Initial the nRF24LE1. Configure to TX mode. Step2: Button is pressed, the nRF24LE1 sending corresponding commands.Step3: If successfully received, displayed on the LCD. Else if fails, Timeout will be determined.
Software design
• E-plate–Use button batteries
– E-plate not work until an interrupts
– The E-plate will process the received information in a short time, and then work on low power consumption module as soon possible.
Software design
Software design
• Communication protocol
– SGN(signture)
– CMD(Command)
– TID(Tag identifier)
– UID(User identifier)
– STA(Status)
Software design
• Encryption
–DES• F-function
• 56bits key.
• 64bits block
Conclusion
• The hardware circuit main chip is RF chip nRF24LE1 and LM3S8962, which is based on the kernel of CORTEX-M3.
• The software includes tag data, receiving data and sending data, and also encryptionalgorithm.