JPH09305878A - Sensor timer alarm circuit for door closing omission of refrigerator or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alarm an open state of a door of a refrigerator, etc., to instruct to close the door when it is kept open for a fixed time and therefor to prevent the unnecessary leakage of cold air enclosed in the refrigerator and also to save the power consumption. SOLUTION: When the door of a refrigerator, etc., is kept closed, a photosensor 7 senses no external light. Then a voltage comparator, a 1st IC 5 and a 2nd IC 6 are turned on, and an output transistor TR 8 is turned off. Under such conditions, an alarm buzzer 9 is not actuated. When the door is opened, the photosensor 7 senses the external light to increase its resistance. Thus, the input voltage of the voltage comparator and the IC 5 exceed a reference level, and a capacitor 15 is charged via resistor. The voltage gradually rises and exceeds the reference voltage level of the IC 6, and the voltage of the IC 6 is set at 0. Thus, a current flows to the base of the TR 8 and the TR 8 is turned on. Then the buzzer 9 works to generate an alarm after a delay time that is set by a delay timer circuit 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the open state of a refrigerator, safe, document store, locker, etc.
A device that sounds an alarm after the desired delay time after opening, especially by sounding an alarm to notify the open state of the refrigerator and closing the door to prevent unnecessary discharge of cold air in the refrigerator and saving electricity bills The field of application in industry is large.

[0002]

2. Description of the Related Art Up to now, there has been no device for sensing the opening of a refrigerator and sounding an alarm. In addition, there are some devices that can be easily installed in lockers, document stores, etc. and sound an alarm, but there are drawbacks such as the device becoming large and costly because the sensor uses a contact switch. It was

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a device for notifying that a user forgets to close the door of a refrigerator or the like mainly used for home use by an alarm, and when he / she is aware of the open state, he / she warns to close the door. This keeps the cold air inside the refrigerator from leaking to the outside more than necessary when the refrigerator is kept open, and the doors can be closed before the freshness of the items declines, saving the electricity bill.

[0004]

In order to achieve the above object, the present invention intends to solve the problems in the door closing forgetting timer alarm circuit of the refrigerator or the like according to the present invention. That is, it is preferable that the present invention is fixed to any place near the opening / closing part in the refrigerator which is already used for home use by using a double-sided tape or the like.

It is usual to open the door of the refrigerator and close the door within tens of seconds within a certain period of time, but even if the refrigerator door is intended to be closed, the items in the refrigerator may be opened due to hitting the inside of the door. There is a thing. When the door opens, the photosensitive sensor detects the light coming in from the outside, the power is input to the circuit, and after a certain time passes through the delay timer circuit, the power is input to the alarm buzzer and the alarm sounds. There is.

When the door of the refrigerator is closed, the light entering from the outside is blocked, the photosensitive sensor is turned off, and the alarm is stopped. As described above, the problem can be solved by the means described above.

[0007]

In the timer alarm circuit for detecting forgetting to close the door of the refrigerator or the like configured as described above, first, when this device is set near the door opening / closing part in the refrigerator and the power of the device is turned on, the door is opened. If it remains closed, the inside of the chamber becomes a dark room and the photosensitive sensor does not detect light, so that the resistance of the photosensitive sensor becomes small and becomes lower than the internal reference voltage of the voltage comparator, and at that time, the first IC turns on.

When the first IC is turned on, the charging voltage of the capacitor passes through the resistor and the discharging current flows in the first IC, and the capacitor becomes lower than the internal reference voltage of the second IC, so that the second IC is turned on and the output transistor is turned off. The alarm does not sound.

Further, when the door of the refrigerator is opened, light enters from the outside, so that the photosensitive sensor senses the light, the resistance of the photosensitive sensor becomes large, and the input voltage of the first IC becomes higher than the internal reference voltage. One IC is turned off and current is 0
become. Then, the capacitor starts to be charged, the voltage gradually rises, the second IC becomes 0, a current flows through the base of the output transistor, the output transistor is turned on, and the device is designed so that an alarm sounds.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, as will be described with reference to the drawings, an embodiment of a door closing forgetting detection timer alarm circuit of a refrigerator according to the present invention, when a switch 1 is turned on in FIG. . In the state where the door is closed, the light does not enter the inside of the cabinet, so that the resistance of the photosensitive sensor 7 becomes small and the input voltage V1 of the voltage comparator and the first IC5 becomes lower than the internal reference voltage of the voltage comparator and the first IC5. Becomes low and the voltage comparator and the first IC 5 are turned on.

When the voltage comparator, the first IC 5, is turned on, the charging voltage of the capacitor 15 passes through the resistor 12 and the voltage comparator,
The discharge current I1 flows through the first IC5. V2 is the second IC6
Since it becomes lower than the internal reference voltage of, the second IC 6 is turned on. When the second IC 6 turns on, the current flows in the I2 direction, so V3 becomes 0, the output transistor 8 turns off, and the alarm buzzer does not sound.

When the door is open, the photosensitive sensor 7 senses the light entering the inside of the cabinet to increase its resistance, and the input voltage V1 of the voltage comparator, the first IC 5 is increased.
Becomes higher than the internal reference voltage of the first IC5, the first IC5 is turned off, and the current I1 becomes zero. Then the resistance 14
Charging starts from the side to the condenser 15 side. When charging starts, the voltage V2 gradually rises, and when it becomes higher than the internal reference voltage of the second IC6, the second IC6 turns off. Then, the direction current I3 flows to the base of the output transistor 8 and the base voltage V3 is applied to turn on the output transistor 8 and the alarm buzzer 9 sounds. The delay timer circuit 3 adjusts the time for sounding the alarm buzzer 9 after opening the door. This is a timer warning circuit for forgetting to close the door of a refrigerator or the like, which is configured as described in the above embodiments.

[0013]

As described above, the present invention can be provided at a small size and at a low cost, can be easily installed inside a refrigerator, etc., and can be closed by sounding an alarm buzzer when forgetting to close the door. A warning circuit device that pays attention to people can prevent unnecessary discharge of cold air in the refrigerator and can save electricity bills. Further, not only the refrigerator but also the closed safe, document storage, locker, etc. can be expected to be widely used for forgetting to close the door.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a forget-to-close door detection timer alarm circuit of a refrigerator or the like according to the present invention.

[Description of symbols] 1 switch 2 power supply 3 delay timer circuit 4 alarm circuit 5 voltage comparator 1st IC 6 voltage comparator 2nd IC 7 photosensitive sensor 8 output transistor 9 alarm buzzer 10 resistor 11 resistor 12 resistor R2 13 resistor 14 resistor R1 15 Condenser 16 Resistor R2

Claims (1)

[Claims] 1. A dry battery or AC when the switch is turned on.
A switch that supplies power to the circuit device from the power supply, a photosensitive sensor that detects light entering from outside when forgetting to close the door, a delay timer circuit that delays after detecting light and sounds an alarm A timer alarm circuit that detects when forgetting to close the door of a refrigerator, etc., which consists of an alarm circuit.