JPH11144187A - Vehicle detector by high-sensitivity earth magnetism sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely detect whether or not a vehicle is present without being affected by withered leaves, dust, fallen snow, rain by detecting the difference between the earth magnetism when a vehicle is present in a specific parking space and that when not by using a microminiature high-sensitivity density earth magnetism sensor and detecting whether or not there is the vehicle. SOLUTION: In the space occupied by a vehicle parked in the parking space, a vehicle detector 2 is installed on the ground. As the installation position of the vehicle detector 2, a place wherein variation of the earth magnetism can distinctively be detected from whether or not there is the vehicle is previously selected. The detection signal from this vehicle detector 2 is inputted to a signal processing circuit 4 through a signal line 3, processed, and sent out to a display device and a monitor device. Namely, the earth magnetism signal detected by the subminiature high-sensitivity earth magnetism sensor 5 of the vehicle detector 2 is amplified by an amplifier 6, processed by a comparator 7, and inputted to a digital output circuit 8, which inputs the digitized signal to a signal processor 4 through the signal line 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle detector using a high-sensitivity geomagnetic sensor for detecting the presence or absence of a vehicle in a parking space and reporting the result.

[0002]

2. Description of the Related Art Optical sensors (such as infrared sensors) are often used to detect the presence or absence of a vehicle parked in a predetermined parking space such as a garage or a parking lot. The light sensor is composed of a light-emitting element that outputs a light beam and a light-receiving element that inputs the light beam and outputs a detection signal. Provide a space where the target vehicle can enter, detect that the light beam is blocked by the monitoring target and the light receiving element cannot receive light, and detect that the monitoring target exists in the predetermined space Was.

[0003]

Since the environmental conditions at the place where the above-mentioned optical sensor is installed are not always favorable, malfunction often occurs due to snow or rainfall, dust such as dead leaves, or contamination of the sensor. Was.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks of the conventional vehicle detection method. The presence or absence of a vehicle is detected by detecting a difference in geomagnetism when a vehicle (a large metal structure) exists in the space and when the vehicle does not exist.

[0005]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an installation state of a vehicle detector according to the present invention. In a space occupied by the vehicle 1 parked in the parking space, a vehicle detector 2 is installed on the ground. The installation position of the vehicle detector 2 is selected in advance based on the presence or absence of the vehicle 1 so that a change in geomagnetism can be clearly detected.

[0006] A detection signal from the vehicle detector 2 is input to a signal processing circuit 4 via a signal line 3 and is signal-processed before being sent to a display device or a monitoring device.

FIG. 2 is a block diagram showing the internal configuration of the vehicle detector 2. A geomagnetic signal detected by an ultra-small high-sensitivity geomagnetic sensor (MR element) 5 is amplified by an amplifier 6, processed by a comparator 7 and then input to a digital output circuit 8. The signal is input to the signal processing circuit 4 via the input terminal 3.

Ultra-small and highly sensitive geomagnetic sensor (MR element) 5
Is an ultra-small high-sensitivity geomagnetic sensor capable of detecting subtle changes in geomagnetism, so that a compact vehicle detector 2 including an amplifier 6, a comparator 7, and a digital output circuit 8 can be configured. Therefore, since the vehicle detector 2 can be embedded at an arbitrary position in the parking space, the vehicle 1 can be mounted without being affected by the installation environment.
Can be detected sensitively as a change in geomagnetism.

[0009]

As described above, the vehicle detector according to the present invention is a small vehicle detector constituted by an ultra-small high-sensitivity geomagnetic sensor, and occupies a very small area when installed in a parking space. And is not affected by environmental conditions. Since the detection of the presence or absence of a vehicle utilizes a change in geomagnetism, the presence or absence of a vehicle can be reliably detected without being affected by dead leaves, dust, snowfall, rainfall, and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an installation state of a vehicle detector according to the present invention.

FIG. 2 is a block diagram showing an internal configuration of a vehicle detector according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle 2 Vehicle detector 3 Signal line 4 Signal processing circuit 5 High sensitivity geomagnetic sensor (MR element) 6 Amplifier 7 Comparator 8 Digital output circuit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01V 3/40 G01V 3/40 G08B 21/00 G08B 21/00 U

Claims (1)

[Claims] 1. A position in a parking space where a change in geomagnetism due to the presence or absence of a vehicle is detected is determined in a parking space, and a vehicle detector configured by a high-sensitivity geomagnetic sensor is installed at the position. A vehicle detector using a high-sensitivity geomagnetic sensor, wherein the presence or absence of a vehicle in a parking space is detected based on a change in geomagnetism detected by the method.