RFID technology has been widely used in the Internet of Things, is a non-contact automatic identification technology that automatically identifies target objects and acquires relevant data through RF signals, identifying no manual intervention. Designed RFID-based bus automatic post-standing system consists of voice module, infrared module, temperature humidity module, single chip, and RFID module, collecting location information of the bus, and measuring the temperature and humidity of the car and the number of passengers in the car. Realize the automation of intelligent newspapers, reduce the work strength of the driver, and improve the safety of vehicle operation.
In the current phase of no ticketing vehicle system, the bus newspaper needs the driver manual control report button. Traditional artificial buttons cannot meet the requirements of the bus system, often false podents, missing, and even simply non-reported, bringing a lot of inconvenience to passengers. The intelligence of the manual station is low, but the button is complex, not only requires the driver to skilled the station device, but also the potential hidden dangers of the security of the public by the safety of the car.
1 To solve this problem, this paper combines single-chip microcomputer, voice chip, and RFID module, and the design plan that can only be used in the bus station system. Designed to realize the function of the bus automatic report, that is, according to the RFID recognition result, the signal is controlled by the single-chip microphone according to the stored station name, and the bus will be automatically reported when the bus will enter and exit, and the vehicle is in the middle of the vehicle. Air information function, thereby truly realizing the intelligence of the bus newspaper station.
2 system overall design plan
The overall design of the system is composed of a voice module, a single chip, and an RFID module. The system determines the position where the vehicle is located, and the signal is transmitted to the microcontroller through the wireless module, and then the voice module is subsequently reported.
2.1 RFID Site Identification Module
This module implements the RFID electronic tag identification and acquisition information of the bus station. Register in each bus station electronic tag, due to the uniqueness of the RFID electronic tag, the system identification site can accurately identify and report. By identifying the electronic tag encoding, the platform information is acquired, and finally transmitted into the RFID report module.
2.2 RFID report module
After receiving the information sent by the bus site, it is compared whether the site is the site in the bus line. From the system, the information is obtained from the system, and the signal to the voice broadcast system is confirmed, and the voice module is played.
3 system hardware structure principle
3.1 Carnes Hardware
The in-vehicle equipment consists of a voice power discharge circuit, a serial communication excuse, a radio frequency transition circuit, a temperature and humidity measuring module, and a voltage regulator circuit. Temperature and humidity measuring module is measured by the vehicle inner single-bus digital temperature sensor DS18B20 (temperature range -55 ~ + 125 degrees Celsius) measures the temperature of the vehicle; the humidity sensor CHR01 measures the humidity of the vehicle; the infrared module detects the number of people to get the number of passengers in the car .
3.1.1 Humidity Sensor ChR01
The humidity sensor of this system uses CHR01. It is applied to a functional polymer film to form a sensitive component with a conductive electrode ceramic substrate, and form an impedance as a relative humidity variant, the conductive mechanism is a water molecule, affects a polymer film. The mobility of internal conductive ions has the characteristics of stable, low drift, high precision, rapid response characteristics, high reliability, water resistance.
3.1.2 Temperature Sensor DS18B20
The DS18B20 digital temperature sensor wiring is convenient, and it can be applied to a variety of occasions after packaging, such as pipeline type, threaded, magnet adsorption, stainless steel package, model, and LTM8877, LTM8874 and so on. The appearance is mainly changed depending on the application.
3.1.3 ISD4004 voice chip
The voice prompt system uses the ISD4004 series produced by US WinBond as a prompt output voice chip ISD4004 series operating voltage 3V, single-chip recording time 8 to 16 minutes, good sound quality, suitable for mobile phones and other portable electronic products. The chip uses CMOS technology, an oscillator, anti-confusing filter, smoothing filter, audio amplifier, automatic stainless, and high-density multi-level flashing storage display. The chip design is based on all operations must be controlled by the microcontroller, and the operational command can be sent to the serial communication interface (SPI or Microwire). The chip uses multi-level direct analog storage technology. Each sampling value is stored in the on-chip flashing memory, so it can be very real, naturally reproduced, music, tone and effect, avoid general solid recording circuit. Quantified noise and "metal sound" caused by quantitative and compression.
3.2 Station-side hardware
The station-side hardware mainly transmits the encoding control circuit, the LED electronic circuit, the radio frequency transition circuit, and the voltage regulator circuit. The radio frequency transgender circuit transmits electronic tag information and accepts vehicle transmission information; the LED electronic circuit displays information from the vehicle to the station.
LED display: The LED display module uses a 1602LCM character liquid crystal display, and the character generated memory (CGROM) inside the 1602 liquid crystal module has stored 160 different dot matrix characters, these characters are: Arabic, English letters, commonly used Symbols, and Japanese fake names, each character has a fixed code.
4 system software structure principle
The system software is written by the C language, which can be divided into RFID electronic tag information is the resolution module to implement information acquisition and identification function; the bus status determination module, the state corresponding to the execution program module implements information processing and processing. The LED displays the information output function with the voice output module.
A simple flow chart for obtaining and identifying and executing the bus RFID electronic tag information. If there is no RFID signal that is received or the electronic label "0000", the instruction is not executed; if the RFID signal is received, if the RFID signal is received, the analysis and change site belongs to the bus. The plan line of the car, if so, start the voice chip report station; if not, the instruction is not issued.
5 Conclusion
According to the design plan of this article, the automatic newspaper station and the platform LED display function have completed the automation of the bus newspaper system, and the bus newspaper station is not allowed to be resolved, providing reliable and cost-controlled bus for the bus system. Multi-function automatic report system car number and temperature, humidity information can be displayed in time on the platform. If you further use the wireless network or wired network to transfer the vehicle site data to the bus management department or the transportation command department, you can monitor the bus operating conditions in real time.
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