Application of RFID Wireless Ground Sensing Parking Space Detection

With the rapid development of the city and the improvement of citizens' living standards, the number of various vehicles in the city is increasing, followed by the corresponding increase in the demand for parking spaces in the main commercial and residential areas of the city. Shanghai has planned to establish large three-dimensional parking lots in several major transportation hubs in the city in 2005. The construction of large parking lots will help to improve the shortage of parking spaces, but it also brings management problems of large parking lots. For example, there are nearly 1200 parking spaces in the parking lot of Shanghai ganghui Plaza. Occasionally, car owners often spend more than half an hour looking for their vehicles because they can't figure out the original parking location. In order to realize the real-time detection of parking spaces in large parking lots, that is, to detect whether vehicles are parked in a parking space, Yingyun has developed a variety of technologies, among which ultrasonic detection technology is the most widely used: put the ultrasonic probe directly above the parking space, calculate and adjust the distance between the probe and the ground in advance. If a vehicle stops, the ultrasonic probe can detect that the probe is away from the "ground" The distance (roof) is changed to inform the backstage that there are vehicles parked in the parking space. The detection accuracy is relatively high. This technology is widely used in foreign countries and some developed cities, but it has some shortcomings in application. First, the problem of ultrasonic scattering and reflection is relatively serious, such as inclined windows, those who do not park in place are likely to reflect ultrasonic, resulting in misjudgment of the signal reception of adjacent parking spaces; Second, installation. The ultrasonic probe must be installed directly above each parking space. The construction volume is not only large, but also unsightly; Third, the cost is high. The price of imported probes (domestic probes often fail to meet the technical requirements) is about 200-300 US dollars. The pressure of cost seriously limits the promotion of this scheme.

Based on the above needs, Shanghai xiupai Electronic Technology Co., Ltd. launched RFID technology combined with geomagnetic induction wireless vehicle detector eflux It can effectively solve the problem of parking space detection and statistics in large parking lots. eFlux Based on show school Watt The design of micro power technology platform can avoid maintenance for about five years, and has certain advantages in performance, cost, system installation and maintenance.

eFlux Characteristics of

High precision: the geomagnetism is basically constant within a certain range, but large ferromagnetic objects will cause huge disturbance to the earth's magnetic field. The geomagnetic sensor can distinguish the change of the earth's magnetic field by 1 / 6000, and the influence on the geomagnetism will reach a fraction of the geomagnetic intensity when the vehicle passes. Therefore, using the geomagnetic sensor to detect the vehicle has very high sensitivity, High accuracy and.

Convenient installation and maintenance, no excavation and construction, and little damage to the ground.

Geomagnetic sensor uses the changing magnetic field when ferromagnetic objects pass through, which is not affected by climate.

Two way high-speed data exchange can be realized between the detector and the receiver, and there is no need to worry about the simultaneous data exchange between each detector and the receiver.

High reliability, working temperature - 40 85 , moisture-proof and impact proof.

High anti-interference: no special requirements for various interference sources.

Ism microwave band is open all over the world without application and payment.

Parking space detection scheme of parking lot

Components of the solution include eflux for detecting whether a vehicle is parked Receiver for receiving and forwarding signals, and application software. eFlux Buried under the surface of the parking space, whenever a vehicle stops, the arrival of the vehicle is detected according to the change of the magnetic field around the ground sense, and after the signal is stable, the signal is sent to the receiver installed in the appropriate position. Similarly, when the vehicle leaves, eflux It can also detect this information according to the change of magnetic field and inform the receiver. The same receiver can detect the use of about 20 parking spaces at the same time.

Schematic diagram of scheme:

The receiver (Reader) can transmit the received signal to the background through 485 / 232. The background application software refreshes the parking space occupation status according to the signal, so that the system can accurately grasp the actual occupation of each parking space. Make maximum use of resources and cooperate with parking guidance screen to disperse traffic flow and slow down congestion during peak traffic hours. At the same time, the problem of "looking for a car" in some super large parking lots is also solved. When the vehicle enters the parking lot, the system automatically allocates parking spaces, drives and parks according to the directions specified by the system, and the owner can accurately find his own parking position.

Product introduction

1. Wireless ground sensing sp-eflux-100

The main technical properties are as follows:

Identification distance up to 40m (with sp-rfs-300, in air)

Operating frequency band 2.4-2.48g

Receiving sensitivity - 80 DBM - 90 dBm

The expected battery life is 5 8 years, and the alarm will be given automatically when the battery power is too low

Sensing range: 0.3m 0.5m

ID number 64 bit

Anti electromagnetic interference 10V / M 0.1 1000MHz am electromagnetic wave

Vibration 10 2000Hz 15g three shafts

Free fall 1500mm concrete floor, twice on each surface