JPH023164Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an automobile air abnormality alarm device that detects and notifies dirt in the air inside an automobile.

The popularity of automobiles has been remarkable, and more and more people are traveling further afield. By the way, during long rides, the air inside the car becomes polluted due to cigarette smoke, car exhaust gas, etc. without realizing it, which has an extremely negative impact on health. . However, until now, there has been no way to easily detect and notify the polluted air inside a vehicle.

This idea was developed in consideration of the above points, and by using an automobile storage battery as a power source and using a solid-state thermal conduction type gas detection element, it is possible to create a low-power, compact, and highly sensitive air abnormality alarm for automobiles. This is what we provide. This invention will be explained below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of this invention. In this figure, 1 is the power supply, which is normally used for 12 volts DC in automobile storage batteries. Reference numeral 2 denotes a constant voltage circuit which outputs a constant voltage regardless of voltage fluctuations of the power supply 1. 3 is an inverter circuit that converts the DC of power supply 1 to AC of about 20KHz. 4 is a sensing element, which uses a solid heat conduction type. 5
is a detection circuit, which together with the detection element 4 constitutes a bridge circuit 6. A switching circuit 7 is operated by the output of the bridge circuit 6. 8 is a multivibrator, 9 is a light emitting diode,
The light emitting diode 9 dims at a period corresponding to the oscillation frequency of the multivibrator 8. 10 is a blocking oscillation circuit, and 11 is a speaker, which generates sound at a period corresponding to the oscillation frequency of the blocking oscillation circuit 10.

To briefly explain the overall operation, constant voltage circuit 2
Power is supplied to each part, and at the same time the sensing element 4 begins to heat up, but until the heating stabilizes and reaches the required resistance value, the bridge circuit 6 becomes unbalanced and outputs, causing the switching circuit to 7 is operated, thereby causing the multivibrator 8 and blocking oscillation circuit 10 to operate, resulting in the light emitting diode 9 blinking and the speaker 11 sounding.
That is, since the light emitting diode 9 always flashes and the speaker 11 sounds when the power is turned on,
This means that you can automatically check whether the device is normal or broken every time.

When the detection element 4 becomes stable beyond this state, the bridge circuit 6 stops outputting, so the light emitting diode 9 stops blinking and the speaker 11 stops ringing.
When the indoor air becomes contaminated and reaches a certain concentration, the resistance value of the detection element 4 decreases, an output is output from the bridge circuit 6, and the light emitting diode 9 and speaker 11 are activated as described above, causing the indoor air to become polluted. Notify.

To explain the above-mentioned sensing element 4, it is of a solid heat conduction type, and is constructed by sintering a metal oxide semiconductor on a platinum wire coil. The metal oxide semiconductor, which is maintained at a constant temperature, adsorbs gas, which improves heat dissipation.As a result, the temperature of the metal oxide semiconductor decreases, and the resistance of the platinum wire coil decreases. The solid heat conduction type sensing element 4 has the advantage of having a faster initial stabilization time and higher sensitivity at low concentrations than a semiconductor type sensing element.

Figure 2 shows an example of the circuit of this invention.
It is shown in comparison with the figure. That is, 1 to 11
1 and 2 respectively indicate the same parts as in FIG. 1, but in FIG. 2 they are indicated using alphanumeric characters instead of numbers.

In Figure 2, Q ₁ to Q ₇ are transistors, R ₁
~R ₂₀ is a resistor, C ₁ ~ C ₁₁ is a capacitor, D ₁ ~ _{D 3}
is a diode, Z _D is a Zener diode, IC is an amplifier, e ₁ is a sensing element (same as sensing element 4 in Figure 1), e ₂ is a compensation element, VR ₁ and VR ₂ are variable resistors,
LED ₁ and LED ₂ are light emitting diodes (same as the light emitting diode 9 in FIG. 1), SP is a speaker (same as the speaker 11 in FIG. 1), and T ₁ and T ₂ are transformers.

To explain its operation, the transistor
Q ₂ , Q ₃ , transformer T ₁ , capacitor C ₃ , resistor
Oscillation occurs in R ₂ , R ₃ , R _{4 ,} etc., and an alternating current voltage is induced on the secondary side of the transformer T ₁ . This is added to the bridge circuit containing the sensing element _e1 . If the air is polluted, an output will be output from the bridge circuit as described above, an input will be applied to the amplifier IC, and an output will be output from it. Therefore, transistor Q ₄ becomes conductive, transistors Q ₅ , Q ₆ , capacitors C ₇ , C ₈ ,
The multivibrator consisting of resistors R ₁₅ to R ₁₈ etc. is activated. Thus, the light emitting diode
LED ₁ and LED ₂ blink alternately.

At the same time, transformer T ₂ , transistor Q ₇ ,
A blocking oscillation circuit consisting of capacitors C ₉ to _{C 1} , resistors R ₁₉ and R ₂₀ , etc. is activated, and the speaker SP sounds at the oscillation frequency.

The variable resistor VR ₁ is used for balance compensation of the bridge circuit, and the variable resistor VR ₂ is used for sensitivity adjustment.

As explained in detail above, this invention uses an automobile storage battery as a power source, and uses a highly sensitive solid-state thermal conduction detection element to provide good initial stability and to regulate the gas concentration at startup and when power is supplied. When the temperature exceeds this value, the alarm system is activated, the light emitting diode emits light, and the speaker sounds, so even if the car is heating or cooling and the windows are closed, the indoor air becomes polluted. This can be clearly communicated. Moreover, since the warning device is activated for a short time when the engine is started, it is easy to determine whether the entire system is normal, and the operator can drive long distances with peace of mind. As described above, this invention can detect indoor air pollution at an early stage, so it can be used to prevent accidents during car maintenance in a garage, detect the degree of air pollution depending on location (open windows to let in outside air), etc. Not only can it be used in conjunction with an automobile air purifier, it can achieve even better health objectives, but it can also be used only when necessary, thus extending the lifespan of the automobile air purifier's filter. It has the advantage of being able to last longer.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of this invention, and FIG. 2 is a diagram showing an example of the circuit. In the figure, 1 is a power supply, 2 is a constant voltage circuit, 3 is an inverter circuit, 4 is a detection element, 5 is a detection circuit, 6 is a bridge circuit, 7 is a switching circuit, 8 is a multivibrator, 9 is a light emitting diode, and 10 is a A blocking oscillation circuit, 11 is a speaker.

Claims (1)

[Scope of utility model registration request] It includes an inverter circuit whose power source is an automobile storage battery and a solid heat conduction type sensing element on the side to be measured. A bridge circuit that outputs output during adsorption,
An air abnormality alarm for an automobile comprising a switching circuit activated by the output of the bridge circuit, and a light emitting diode and a speaker controlled by the switching circuit.