JPH03261889A - Wind velocity sensor - Google Patents

Abstract

PURPOSE:To reduce the size of a wind velocity sensor and simplify it by intermittently changing a voltage applied to a thrmosensitive element, thereby reducing a time for which a sensor is heated by applying the high voltage and increasing the time for which the sensor is not heated by applying the low voltage. CONSTITUTION:In measuring a wind velocity, when a timer SW1>>24 is operated, an output sharply changes to the minus side because RS RQ. A current flowing in a thermistor RTh 20 quickly increases and the temperatures of RT and RTh 20 begin to rise. When SW1 24 is turned OFF, the temperature rise and RTh with a low resistance and a resistor RS 22 become a serial condition, the current flowing in RTh 20 quickly decreases, heat is scarcely generated, at the same time the resistance of RTh 20 is low and a potential at point A is changed to a plus side. At this time, the temperature of RTh 20 is higher than that of an atmosphere, RTh 20 is cooled by a difference between its temperature and that of the atmosphere and wind around RTh 20 and returned to its prior condi tion. Since, when the temperature has be determined, a cooling rate is deter mined by the wind velocity and the condition of heating when SW1 24 is ON is determined by the wind velocity, the magnitude of DELTAVout is determined by the wind velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wind speed sensor that uses a small-sized (low heat capacity) temperature sensor to measure temperature and wind speed with a small amount of electric power. As a result of extremely low power consumption, it is also possible to incorporate this sensor into a remote control device such as an air conditioner and run it on batteries, allowing the operator to control the air conditioner based on the conditions in his or her location. You will be able to do this.

In addition, HEPA (High
Efficiency Particulate
It can also be used to detect clogging of Air) filters, and as a contact sensor to detect contact with a partner.

[Conventional technology]

As a wind speed sensor using a temperature sensor, a hot wire anemometer using platinum or tungsten wire, or an indirectly heated sensor using a thermistor or thermocouple with an insulated heater attached as the sensor, can be used to measure the degree of cooling. A method that detects the wind speed has traditionally been used. The former has problems in terms of directivity, and the latter has problems in response speed, and in recent years constant temperature type anemometers that use direct thermistors have come into widespread use.

However, conventional methods, including direct heating types, require high power consumption because the sensor section is constantly heated.
It was impossible to use batteries for a long time as a power source.

Figure 1 shows a comparison of schematic structural diagrams of thermistor anemometers.
FIG. 1(b) shows an example of the configuration of the new system. In an anemometer using a conventionally used temperature sensor, for example, in the case of a thermistor anemometer, two thermistors 10 and 11 are used as shown in FIG. In contrast to passing a current to raise the temperature and checking the degree of cooling by the wind, a large current is not passed to the temperature compensation element 11 side to detect the wind temperature and is used for the purpose of temperature compensation. There is.

As mentioned above, according to the conventional technology, the power consumption becomes extremely large and it is not possible to incorporate the sensor into the remote controller, so it has to be incorporated into the main body of the device such as an air conditioner. Therefore, it is impossible to control the air conditioner depending on the conditions in the place where people live. In particular, since the flow of wind varies greatly depending on the location, it is desirable to control the wind based on the conditions of the location where the person is actually located.

[Problem to be solved by the invention]

An object of the present invention is to provide a wind speed sensor that uses a single temperature sensor to measure temperature and wind speed with little power consumption, and thereby allows the sensor to be incorporated into the operating device of a device that is remotely controlled. It becomes possible.

The wind speed sensor of the present invention has the following advantages: (2) it can detect wind speed and wind temperature with one sensor, and the sensor part is economically constructed; (2) it can withstand long-term use with low power consumption; There are two major characteristics.

An object of the present invention is to take advantage of this feature to provide a wind speed sensor that incorporates the sensor into a remote control device such as an air conditioner.

Conventional wind speed sensors using thermal sensors consume several tens of milliwatts of power continuously to raise the temperature of the sensor, and normally use another sensor for temperature compensation, but the wind speed sensor of the present invention The sensor uses only one sensor,
The voltage is changed intermittently, and when a high voltage is applied, the wind speed is detected, and when a low voltage is applied, the temperature is detected. This makes it possible, for example, to incorporate a sensor into a remote control unit for an air conditioner to detect not only the temperature but also the flow of air to achieve comfortable air conditioning.

[Means to solve the problem]

The configuration of the present invention is as shown below. That is, the present invention has the following features: In a wind speed sensor that uses a heat-sensitive element as a sensor, the voltage applied to the heat-sensitive element is intermittently changed, the time for applying a high voltage to heat the sensor is shortened, and the time for applying a low voltage is shortened. It has a configuration as a wind speed sensor characterized in that the capacity of the power source is reduced by changing the voltage of the sensor circuit in a pulsed manner so as to lengthen the time during which the sensor is not heated; or The wind speed sensor is characterized in that the sensor functions as a temperature sensor when the voltage level is low, and the wind speed is detected by obtaining a wind speed signal from a change in the state of the sensor when a high voltage is applied in a pulsed manner. The wind speed sensor has a configuration as a wind speed sensor. (3) Difference in signal voltage from the sensor when a high voltage is applied to the wind speed sensor and the output of the sensor reaches its maximum ΔV0. ．． Alternatively, in the wind speed sensor, the sensor is heated by a high voltage applied to the sensor in a pulsed manner, and the high voltage is suddenly applied to the sensor. When the voltage returns to the original low voltage again, the wind speed is detected by the time it takes for the output from the sensor to return to the original output state again. The wind speed sensor has a configuration as a wind speed sensor characterized in that when a high voltage is applied to the sensor in a pulsed manner, the heating rate of the sensor is measured and used as a wind speed signal, or alternatively, in the wind speed sensor, The present invention has a configuration as a wind speed sensor characterized by using only one heat-sensitive element in the sensor and configured to detect wind temperature and wind speed.

[For production]

FIG. 2 is a basic circuit diagram of the wind speed sensor according to the present invention,
FIG. 3 is an explanatory diagram of the principle of wind speed measurement using the circuit shown in FIG. 2.

As shown in Figure 2, a bridge is constructed with a thermistor R and 20 on one side, and an E-volt power source 21 is powered by a battery.
Connect to. For the resistor R822, a resistor RQ23 having a sufficiently lower resistance value than R522 is connected in series with the timer contact 5W124 as shown in the figure, and then connected in parallel.

Connection point A between R,,20 and R522, and resistor R+25,
The signal between the connection point B of R726 and the output signal V, , 2
Set it to 7.

Assuming that the wind speed is measured intermittently, consider the following. When timer SW, 24 is OFF, RT, 20, R,
It is assumed that the bridge of 22, R125, and R126 is balanced and the output V, □ 27 is 0.

When measuring wind speed, timer 5WI24 operates at the beginning and outputs 5W.
When 124 is turned on, the potential at point A drops rapidly because of the relationship Rs>RQ, and the output swings significantly negative as shown in Figure 3 (■). At the same time, since RQ23 has become low, the current flowing through the thermistors R7 and 20 increases rapidly, and the temperature of the thermistors R□ and 20 begins to rise due to Joule heat. The rising curve ■ at this time changes depending on the ambient temperature and wind speed.

When timer 5WI24 turns OFF, thermistor R020 and resistor R522, whose temperature rises and the resistance decreases,
are connected in series, and the thermistor R'rb2
Since the current flowing through 0 is drastically reduced, the heat generated by thermistor R020 is almost eliminated, and at the same time, the resistance of R020 is lowered, so the potential at point A is swung to the positive side as shown by ■. At that time, the temperature of the thermistor Rtb20 is higher than the atmosphere, so it is cooled by the difference in temperature with the atmosphere and the wind around the thermistor RTb20, and the timer SW is
, 24 returns to the state before the operation. If the temperature is determined, the cooling rate is determined by the wind speed, and the timer SW +
Since the heating state (indicated by the change in the H curve) when 24 is turned ON is determined by the wind speed, the magnitude of △V o s t when timer SW 24 is OFF is determined by the wind speed. They have a fertile relationship.

Therefore, (1) The wind speed can be detected from the magnitudes of △V and □ shown in FIG. 3 when the timer 5W124 is turned off. (2) Timer SWI 24 is O
After becoming FF, the wind speed can be detected from the time until the output V a m l becomes zero again. (3) The wind speed can be detected from the rate of change in voltage at the H portion after the timer SW 24 is turned on.

The wind speed can be determined by any one of these (1), (2), and (3). With this method, the wind speed can be detected intermittently, such as once every minute or once every five minutes, as needed, so the wind speed of an air conditioner, etc. can be controlled remotely using a handheld controller. This can be done by incorporating a thermistor inside.

〔Example〕

FIG. 4 is a basic experimental circuit diagram of a wind speed sensor as an embodiment of the present invention.

For the purpose of obtaining basic data, an experiment was conducted using the values shown in Figure 4.

Thermistor R020 has 7.416Ω at 0°C, 0°
The value of B calculated between C and 100° C. was 3350Ω.

A decade resistor is used for the resistance of R226, and when the timer 5WI24 is OFF for each ambient temperature, the output V,
,,I adjusted R,25 so that 27 becomes a cello.

Use a 5.247Ω resistor for R+25, and Rs=l
OkΩ, RQ=0.05Ω, DC2.5V for power supply E
was used. R72 to make V, , -OV at each temperature
As shown in Table 1 of the value of 6, before timer 5WI24 turns on (SWI24 is OFF), zero balance is achieved and the time for timer SW and 24 to turn on is set to 10 seconds. The results of the experiment are shown in Figure 5.

As can be seen from the above results, △V e
Since ut takes a different value depending on the temperature, temperature compensation must be performed for ΔV6.

In the circuit shown in Figure 3, the balance of the bridge was adjusted using R226 before the timer 5WI24 was turned ON, but in the actual circuit, the output before the timer SVV+24 was turned ON, and the output immediately after the timer SVV+24 was turned OFF. Since the difference between V and □27 can be quickly read and used as the value of △Vo1, in a circuit using a microcomputer, it is necessary to set the zero balance of the circuit by using the temperature compensation element 11 (see Fig. 1).
There is no need to use (see a)).

Table 2 shows the average value of the ratios of △■ and □ at each temperature for each wind speed.

Since temperature compensation is performed after amplifying the signal ΔV, the data is shown in the table as the output data of an amplifier circuit with an amplification factor of 10 times.

Table 2 Effect of temperature on output at each wind speed The circuit shown in Figure 7 is an example of detecting airflow using the method described above.

The temperature is detected from the output of the amplifier 71 when the 5W180 driven by a timer by a microcomputer is OFF, and the temperature is detected from the output of the amplifier 71 when the 5W180 is ON.
It is configured to extract a wind speed signal from a change in the state of the output of No. 2.

In FIG. 7, Ro is a thermistor 70 according to the method of the present invention which serves for wind speed and temperature sensing.

The amplifier 71 circuit is a temperature detection circuit, and the temperature is Rth7.
0, RQ73, R174 and R275. The circuit of amplifier 72 is for wind speed detection circuit, R970, RQ73 and R,76, RM7.
7, and RN78 and RA79 (RB, Rc,
The wind speed is detected at the bridge section, which is composed of wind turbines (including Ro and RE).

The outputs of the amplifiers 71 and 72 are A/D converted and input to the microcomputer, and the wind speed signal is temperature-compensated by referring to the average value of the ratios in Table 2, so that the wind speed has little to do with temperature. signal.

The S W + contact 80 is driven by a timer by a microcomputer, and is turned ON-OFF in an intermittent time mode appropriately selected in consideration of the capacity of the battery of the power source.

The resistances Ra, Rc, Ro, and RE of the bridge circuit are opened and closed by commands issued by the microcomputer based on the temperature signal of the output of the amplifier 71, and the value of R226 shown in Table 1 (78 in Fig. 7) is changed depending on the temperature at that time. .79). As a result, when detecting ΔV, . . . , the voltage level does not fluctuate too much, and ΔV a m l can be detected centered around an almost constant voltage level.

In addition to detecting the wind speed by measuring △V0.1 as described above, the timer 5WI80 is used as shown in Figure 3.
A method using the time from when the thermistor 70 is turned off until the thermistor 70 is cooled to the initial temperature, or a method using the timer SW+8
A method may be used in which the speed at which the thermistor 70 is heated and its resistance decreases when 0 is turned on is determined from the magnitudes of d V, , l /d t.

〔Effect of the invention〕

Conventional wind speed sensors, for example, either constantly supply a current to the wind sensor and detect the wind speed from changes in the terminal voltage, or immediately change the current flowing through the thermistor when the temperature of the thermistor changes due to a change in wind speed. The wind speed signal was obtained from the current flowing through a thermistor in a constant-temperature circuit that returns the temperature to its original value. Therefore, a large amount of electric power is continuously required, and it is practically impossible to drive it with a small capacity battery.

The present invention paves the way for the wind speed sensor to be applied to purposes such as incorporating a wind speed sensor into a remote control device such as a cooler, determining the level of airflow speed, and automatically maintaining a comfortable airflow. It is something.

In addition, since the structure of the sensor itself can be made very small and simple, it has the effect of expanding the field of use mechanically and economically.

The economic effect is extremely large in fields of use such as air conditioners that do not require continuous data, but only require wind speed data every 1 minute or every 5 minutes.

Also, depending on how it is used, a sensor can be attached to the tip and used to determine whether the tip has touched an object based on the difference in ΔV ou when it is not touching an object and when it is touching an object.

Further, in this invention, only one thermistor is used as shown in A in FIG. 1, so it is possible to reduce the size and is highly economical.

The wind speed sensor of the present invention (1) has an economical sensor unit that detects wind speed and wind temperature with one sensor, and (2) can withstand long-term use with low power consumption. There are two major characteristics.

An object of the present invention is to take advantage of this feature to provide a wind speed sensor that incorporates the sensor into a remote control device such as an air conditioner. Conventional wind speed sensors using thermal sensors consume several tens of milliwatts of power continuously to raise the temperature of the sensor, and normally use another sensor for temperature compensation, but the wind speed sensor of the present invention In the sensor, the sensor is 1
The voltage is changed intermittently, and when a high voltage is applied, the wind speed is detected, and when a low voltage is applied, the temperature is detected. This has made it possible, for example, to incorporate a sensor into the remote control unit of an air conditioner to detect not only the temperature but also the flow of air to achieve comfortable air conditioning.

[Brief explanation of drawings]

Fig. 1 shows a schematic structure example of the sensor section of the conventional method (A) and the new method (B), Fig. 2 shows the basic circuit diagram, Fig. 3 shows the principle diagram of wind speed measurement, and Fig. 4 shows the basic circuit diagram. The figure shows a basic experimental circuit diagram, Figure 5 shows the results of an experiment using the circuit in Figure 4, and Figure 6 shows the relationship between ambient temperature and output change (△V,,, ) using wind speed as a parameter. FIG. 7 shows a circuit configuration diagram as an embodiment of the airflow sensor according to the present invention. lO... Wind sensing element, 11... Temperature compensation element, 20
゜70... Thermistor Rt121... Power supply (E volts), 22.76-... Resistor R5, 23, 7 24, 80... Contact switch SW1, ), 25.74... Resistor R1, 2 R2, 27... Output signal V, , , ? (ICI),
72...Operational amplifier (...Resistance RM, 78...Resistance RN, 73...Resistance RQ, (Timer SW 6.75...Resistance l...Operational amplifier IC2), 77 9...Resistance R.A.

Claims (6)

[Claims] (1) In a wind speed sensor that uses a heat-sensitive element as a sensor, the voltage applied to the heat-sensitive element is intermittently changed to shorten the time it takes to heat the sensor by applying a high voltage, and to heat the sensor by applying a low voltage. A wind speed sensor characterized in that the capacity of the power supply is reduced by changing the voltage of the sensor circuit in a pulsed manner so as to lengthen the time during which the sensor circuit is not operated. (2) When the voltage level in the wind speed sensor is low, the sensor functions as a temperature sensor, and the wind speed is detected by obtaining a wind speed signal from the change in the state of the sensor when a high voltage is applied in a pulsed manner. The wind speed sensor according to claim 1, characterized in that: (3) Difference in signal voltage from the wind speed sensor immediately before applying a high voltage to the wind speed sensor and when the high voltage is applied and the output of the sensor reaches its maximum △V_o
The wind speed sensor according to claim 2, wherein the wind speed is detected based on the magnitude of _u_t. (4) In the wind speed sensor, when the sensor is heated by a high voltage applied to the sensor in pulses and the high voltage suddenly returns to the original low voltage, the output from the sensor returns to the original output state. 2. The wind speed sensor according to claim 1, wherein the wind speed is detected based on the time it takes for the wind speed to return to . (5) The wind speed sensor according to claim 1, wherein when a high voltage is applied to the sensor in a pulsed manner, the heating rate of the sensor is measured and used as a wind speed signal. (6) In the wind speed sensor, one heat-sensitive element is attached to the sensor.
2. The wind speed sensor according to claim 1, wherein the wind speed sensor is configured to detect wind temperature and wind speed.