JPH08200942A - Opening-closing sensing circuit for refrigerator door utilizing hole sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit for sensing closing of a refrigerator door, utilizing a Hall sensor capable of sensing a closing state of the refrigerator door correctly by utilizing Hall effect induced from the Hall sensor at closing of the refrigerator door. SOLUTION: This circuit comprises a permanent magnet 100 provided on a specified position of a refrigerator door and applying a magnetic field, a Hall sensor 200 provided on a specified position of a refrigerator body and corresponding to the permanent magnet 100 and conducting switching operation by utilizing the Hall effect induced by the change in the magnetic field by closing the refrigerator door, and a microcomputer 300 sensing a closing state of the refrigerator door based on a voltage input by the switching operation of the Hall sensor 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator door open / close detection circuit, and more particularly, a permanent magnet is attached to a predetermined position of a refrigerator door, and a hall sensor corresponding to the permanent magnet is attached to a main body of the refrigerator. The present invention relates to a refrigerator door open / close detection circuit using a hall sensor capable of accurately detecting the open / closed state of the refrigerator door by utilizing the Hall effect induced by the hall sensor when the refrigerator door is opened / closed.

[0002]

2. Description of the Related Art In a conventional refrigerator door open / close detection circuit,
As shown in FIG. 3, the refrigerator compartment door 20 of the body 10 of the refrigerator is shown.
And permanent magnets 40 and 50 mounted on the lower part of the freezer compartment door 30 for applying a magnetic field, and mounted on the upper part of the refrigerator compartment 60 and the lower part of the freezer compartment 70 corresponding to the permanent magnets 40 and 50, respectively. The refrigerating compartment door 20 and the freezing compartment door 30 are constituted by switching units 80 and 90 which are turned on / off according to a change in magnetic field generated by opening / closing.

As shown in FIG. 4, the switching units 80 and 90 have a power source voltage Vc on one side through a resistor R1.
The reed switch 11 is connected to the terminal c, and the other side is grounded, and is turned on / off according to the change in the magnetic field generated by opening and closing the refrigerator doors 20 and 30, and the reed switch 11 through the resistor R2. The microcomputer 12 is connected to the one side terminal and detects the open / closed state of the refrigerator door by the voltage input through the resistor R2 when the reed switch 11 is turned on / off.

The operation of the conventional refrigerator door open / close detection circuit thus constructed will be described with reference to FIGS. 3 and 4. FIG. First, when the user closes the refrigerating compartment door 20, as shown in FIG. 3, the permanent magnet 40 mounted on the upper part of the refrigerating compartment door 20 has the reed switch of the switching unit 80 mounted on the upper part of the refrigerating compartment 60. It contacts 11 and applies a magnetic field.

At this time, as shown in FIG. 4, the reed switch 11 is turned on by the magnetic field applied from the permanent magnet 40, and the power supply voltage Vcc flows through the resistor R1 and the reed switch 11 to the ground side. Low level voltage is V
It is input to the microcomputer 12 from cc. Therefore, the microcomputer 12 to which the low level voltage is input senses that the refrigerating compartment door 20 is closed and performs a control operation accordingly.

Further, even when the user closes the freezer compartment door 30, the permanent magnets 5 attached to the lower portion of the freezer compartment door 30.
0 contacts the reed switch 11 of the switching unit 90 mounted on the lower part of the freezer compartment 70 to apply a magnetic field, and the same operation as when the refrigerator compartment door 20 is closed is performed.
On the other hand, when the user opens the refrigerating compartment door 20, as shown in FIG. 3, the permanent magnet 40 mounted on the upper part of the refrigerating compartment door 20 and the switching section 80 are separated, and the reed switch 11 of the switching section 80 is separated. Since no magnetic field is applied to
The reed switch 11 is turned off, and the high level voltage is V
cc is input to the microcomputer 12 through the resistors R1 and R2, and the microcomputer 1
2 detects the open state of the refrigerator door 20 and performs control operation accordingly.

Further, even when the user opens the freezer compartment door 30, the switching magnet 9 mounted on the lower part of the freezer compartment 70 has the permanent magnet 50 mounted on the lower part of the freezer compartment door 30.
Since the magnetic field is separated from 0 and no magnetic field is applied to the reed switch 11 of the switching unit 90, the same operation as when the refrigerator compartment door 20 is opened is performed.

[0008]

However, in the conventional open / close detection circuit for a refrigerator door, the reed switch has a problem that it malfunctions due to a minute magnetic field change because it shows a sensitive reaction to the magnetic field. Since it is enclosed in a pipe, it has a problem that it is vulnerable to impact and becomes expensive.

In order to solve such a problem, an object of the present invention is to install a permanent magnet at a predetermined position of a refrigerator door,
After mounting the Hall sensor corresponding to the permanent magnet on the body of the refrigerator, the Hall effect generated in the Hall sensor according to the change of the magnetic field due to the opening and closing of the refrigerator door is used to detect the opening and closing state of the refrigerator door, An object of the present invention is to provide a refrigerator door open / close detection circuit using a hall sensor that is resistant to impact and can accurately detect the open / closed state of the refrigerator door.

[0010]

To achieve the above object, the present invention provides a permanent magnet mounted at a predetermined position of a refrigerator door for applying a magnetic field, and a permanent magnet at a predetermined position of a main body of a refrigerator. Correspondingly mounted Hall sensor that performs switching operation using the Hall effect induced by the change of magnetic field by opening and closing the refrigerator door, and opening and closing the refrigerator door by the voltage input by the switching operation of the Hall sensor It consists of a microcomputer that senses the state.

In such a structure, when the refrigerator door is opened and closed, a change in magnetic field occurs in the hall sensor, and the hall sensor performs a switching operation due to the change in the magnetic field.
The microcomputer detects whether the refrigerator door is open or closed based on the voltage input by the switching operation of the hall sensor.

[0012]

As is well known, the Hall effect means that when a current is applied to a metal or a semiconductor and a predetermined magnetic field is applied at a right angle to the metal or the semiconductor, the Hall effect is applied in a direction perpendicular to the current and the magnetic field. The effect of electromotive force. And
The hall sensor is a switch type sensor that is turned on / off by a change in a magnetic field as a sensor using such a hall effect.

As shown in FIG. 1, the refrigerator door open / close detection circuit using the hall sensor according to the present invention is mounted at predetermined positions of the refrigerator compartment door 20 and the freezer compartment door 30 in the refrigerator shown in FIG. 3, respectively. A permanent magnet 100 for applying a magnetic field, and a refrigerator compartment 60 corresponding to the permanent magnet 100.
And the refrigerator door 2 installed at a predetermined position in the freezer compartment 70.
Hall sensor 2 that performs switching operation by utilizing the Hall effect induced by the change in magnetic field by opening and closing 0, 30
00 and a microcomputer 300 for detecting the open / closed state of the refrigerator door based on the voltage input by the switching operation of the hall sensor 200.

Further, in the Hall sensor 200, as shown in FIG. 2, a magnetic field sensing unit 201 for generating a predetermined induced voltage by a magnetic field formed by the permanent magnet 100, and a magnetic field sensing unit 201 for generating the induced voltage. The Schmitt trigger 202 which outputs a voltage of a predetermined level by the induced voltage, the base is connected to the output terminal of the Schmitt trigger 202, the collector is connected to the microcomputer 300, the emitter is grounded, and the Schmitt trigger 202 is connected. It is composed of a transistor 203 which is turned on / off by an output.

The operation of the open / close detection circuit for the refrigerator door using the Hall sensor according to the present invention thus constructed will be described with reference to FIGS. 1 and 2. First, as shown in FIG. 3, two permanent magnets 100 for applying a magnetic field are attached to predetermined positions of the refrigerator doors 20 and 30 of the refrigerator body 10, respectively, and when the refrigerator doors 20 and 30 are closed, the two The two Hall sensors 200 are mounted at predetermined positions in the refrigerating room 60 and the freezing room 70 so as to be in contact with one of the permanent magnets 100.

Thereafter, when the user closes the refrigerator doors 20 and 30, the two permanent magnets 100 attached to the refrigerator doors 20 and 30 are attached to the refrigerating chamber 60 and the freezing chamber 70 at predetermined positions. The two Hall sensors 200 are brought into contact with each other, and a magnetic field is applied to the two Hall sensors 200. At this time, in the magnetic field sensing units 201 of the two Hall sensors 200, as shown in FIG.
A magnetic field is formed by the two permanent magnets 100, and the Hall effect is induced by these magnetic fields to output a predetermined induced voltage.

Next, the Schmitt trigger 202
Is operated by the induced voltage output from the magnetic field sensing unit 201, and outputs a high level voltage to the transistor 203.
To turn on the transistor.
Therefore, the power supply voltage Vcc is equal to the resistance R1 and the transistor 20.
3 and flows to the ground side, and low level voltage
2 is input to the microcomputer 300, and the microcomputer 300 receives the refrigerator door 2
Detects that 0 and 30 are closed.

On the other hand, when the user opens the refrigerator doors 20 and 30, the two permanent magnets 100 mounted at the predetermined positions on the refrigerator doors 20 and 30 correspond to the refrigerator compartment 60 and the freezer compartment 70, respectively. The magnetic field is not formed in the two Hall sensors 200 separated from the two Hall sensors 200 mounted in the predetermined positions. At this time, in the magnetic field sensing unit 201 of the two Hall sensors 200, as shown in FIG. 2, the magnetic field formed by the two permanent magnets 100 disappears, the Hall effect disappears, and the induced voltage is not generated, so that the low level is generated. Is output.

Then, the Schmitt trigger 202 operates by the low level voltage output from the magnetic field sensing unit 201, outputs the low level voltage to the gate of the transistor 203, and turns off the transistor 203. Therefore, the high level power supply voltage Vc
c is input to the microcomputer 300 through the resistors R1 and R2, and the microcomputer 300
Senses that the refrigerator doors 20 and 30 are open, and performs the control operation accordingly.

[0020]

As described above, according to the present invention, a permanent magnet is attached to a predetermined position of a refrigerator door, and a Hall sensor is attached to the refrigerator body corresponding to the permanent magnet. Hall sensor performs switching operation according to changes in the temperature to detect the open / closed state of the refrigerator door, provides a circuit that is strong against shocks when the refrigerator door is opened / closed, and uses low-cost elements to reduce costs. This has the effect of enabling accurate open / close detection.

[Brief description of drawings]

FIG. 1 is an open / close detection circuit diagram of a refrigerator door according to the present invention.

FIG. 2 is a detailed circuit diagram of a Hall sensor according to the present invention.

FIG. 3 is a view showing a mounting position of a conventional opening / closing detection circuit of a refrigerator door.

FIG. 4 is a detailed circuit diagram of a conventional switching unit.

[Explanation of symbols]

 100 ... Permanent magnet 200 ... Hall sensor 201 ... Magnetic field sensing unit 202 ... Schmitt trigger 203 ... Transistor 300 ... Microcomputer

Claims (2)

[Claims] 1. A refrigerator door open / close detection circuit using a hall sensor, comprising: a permanent magnet attached to a predetermined position of the refrigerator door; and a permanent magnet attached to a predetermined position of a refrigerator body in correspondence with the permanent magnet. And a hall sensor that performs a switching operation using a Hall effect induced by a change in magnetic field caused by opening and closing the refrigerator door, and detects the opening and closing state of the refrigerator door based on a voltage input by the switching operation of the hall sensor. A refrigerator door open / close detection circuit using a hall sensor, which is equipped with a microcomputer. 2. The Hall sensor is configured to generate a predetermined induced voltage by a Hall effect induced from a change in the magnetic field, and a voltage of a predetermined level from the induced voltage generated by the magnetic field sensor. A Schmitt trigger for outputting, a base connected to the output terminal of the Schmitt trigger, a collector connected to the microcomputer, an emitter grounded, and a transistor turned on / off by the output of the Schmitt trigger. An open / close detection circuit for a refrigerator door using the hall sensor according to Item 1.