JPH045332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improving the accuracy of water depth measurement in a portable device with a water depth measurement function.

[Conventional technology]

In general, water depth measurement is performed by measuring pressure by utilizing the fact that pressure and water depth values are in a comparative relationship. The relationship between pressure and water depth value is shown by the following equation.

g×ρ×ε×D=p where: g: gravitational acceleration ρ: density ε of pure water at 4° C.: specific gravity D: water depth p: pressure. Based on this formula, let's consider the relationship between pressure and water depth from the perspective of accuracy. The gravitational acceleration g varies depending on the location on the earth, but the difference is negligible. Specific gravity ε
is the difference in water temperature and water quality environment at the time of measurement (freshwater or seawater)
It has different values depending on the The effect of water temperature is that as the temperature rises, ε decreases, and as the temperature decreases, ε increases, but this difference is small and can be ignored. However, the specific gravity ε varies greatly, ranging from 1 to 1.05, depending on the water quality environment (freshwater or seawater) at the time of measurement. For example, the pressure at a depth of 100 m for freshwater with a specific gravity of 1 is p1
shall be. Then, for seawater with a specific gravity of 1.05, the depth value at the pressure point p1 is 1/1.05 of the former value, ≒ 95.2 m. In other words, there will be a difference of 4.8 m between the two at the same pressure point p1. This difference due to specific gravity cannot be ignored as water depth values are measured by measuring pressure.

[Problem that the invention seeks to solve]

Therefore, no matter how accurate a pressure detection sensor, sensor output signal processing circuit, and adjustment to improve accuracy are used in manufacturing a depth gauge, the depth value is measured by measuring pressure. As mentioned above, errors due to specific gravity have been considered to be errors that cannot be ignored.

The present invention solves these drawbacks, and
The purpose is to provide a portable device with a water depth measurement function that reduces errors caused by differences in specific gravity in a water depth meter that measures water depth by measuring pressure.

[Means for solving problems]

The portable device with water depth measurement function of the present invention includes a water quality environmental value detection means for detecting two or more types of water quality environmental levels, a water quality environment storage means in which water quality environmental values corresponding to the detected water quality environmental levels are stored in advance;
water quality environment selection means for selecting a water quality environment value stored in the water quality environment value storage means based on the water quality environment level detected by the water quality environment detection means; A water depth value calculating means for calculating a water depth value based on a detected pressure value.

[Effect]

The effects of the present invention will be described below in order.

(1): The level of the water quality environment at the time of measurement (for example, fresh water, seawater with low specific gravity (low concentration), high specific gravity (high concentration)) by the water quality environment detection means.
seawater) is detected.

(2): Based on the detected water quality environmental level, a water quality environmental value stored in advance in the water quality environmental value storage means is selected by the water quality environmental value selection means.

(3): A water depth value is calculated by a water depth calculation means based on the selected water quality environmental value and the detected pressure value measured by the pressure sensor.

(4): The calculated water depth value is displayed on the display.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples. FIG. 1 shows a block diagram of an embodiment of the present invention. 1 is a pressure sensor that detects water pressure; 2 is a pressure sensor drive circuit that drives the pressure sensor; 3 is a signal processing circuit that converts the output signal from the pressure sensor into a desired measurement signal; 4
Reference numeral 5 indicates a display section for displaying water depth values, 5 indicates water quality environment detection means, and 6 indicates water quality environment value selection means. Reference numeral 7 is a one-chip microcomputer, which is equipped with a water quality environment storage means that stores water quality environment values in advance, and a water depth value calculation means that calculates a water depth value based on the selected water quality environment value and the pressure signal from the signal processing means. There is. FIG. 2 shows the one-chip microcomputer and peripheral circuits in more detail. The area surrounded by the dotted line in the figure is the one-chip microcomputer 7. Water quality environmental value
It is stored in ROM (read only memory) 8. The signal from the water quality environmental value selection means 6 is IO
Input to port (input/output device) 9. Depending on the input status to the IO port, a water quality environment value corresponding to the water quality environment level stored in advance in the ROM is selected. The water depth value is calculated using the ALU (arithmetic unit) based on the selected water quality environmental value and the pressure signal input from the signal processing circuit 3 through the IO port 9.
10. The calculated water depth value is IO
It is displayed on the display section 4 through port 9. In addition,
11 is RAM (random access memory), 12
is an oscillation circuit. Next, the water quality environmental level detection means will be explained in detail.

FIG. 3 shows a cross-sectional structure of a water quality environment detection means in an embodiment of the present invention. In the figure, 13 is a cover glass, 14 is a transparent electrode formed on the cover glass, 15 is a movement, 16 is an outer case, 4 is a display section, and 17 is a waterproof material that fixes the cover glass 13 and the outer case 16 at the same time. 18 is a conductive member for establishing electrical connection between the transparent electrode 14 and the circuit section of the water environment detection means; 19 is a back cover; and 20 is a gasket. Note that to control the power source and water depth measurement of the device shown in FIG. 3, an operation switch is required to protrude outward from the case 16, and although it is actually provided, it is not shown.

FIG. 4 is an enlarged view of the transparent electrode section, and the transparent electrode is composed of a transparent electrode member 14a and a transparent electrode insulating member 14b.

FIG. 5 is a plan view of the transparent electrode section. Two transparent electrodes 14 are formed. 18 is the electrically conductive member mentioned above. As shown in FIG. 6, during diving, the transparent electrodes come into contact with freshwater or seawater, and a resistance R (20 in the figure) is generated between the electrodes.

FIG. 7 shows the circuit configuration of the water quality environment detection means and the water quality environment value selection means for selecting the water quality environment value corresponding to the detected water quality environment level.

In the figure, 14 is a transparent electrode, and 20 is a resistance R generated during diving, and this resistance value varies depending on the water quality environment.
In the case of fresh water, the resistance value is large, and in the case of seawater, the resistance value is small. Furthermore, as the concentration of seawater increases, the concentration of ions (NA ⁺ ions, Cl ^- ions, etc.) in seawater increases, and the electrical conductivity increases, so the resistance value of resistor R changes, and accordingly a
The potentials of the points are different. R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ are resistances for leveling the water quality environment, and appropriate resistance values are selected in advance based on experimental confirmation. 21, 22, and 23 are comparators, and each comparator's non-inverting input terminal (described as in the figure)
The potential at point a is input to the inverting input terminal (described as in the figure), and the potential at point b divided by R ₂ , R ₃ , R ₄ , and R ₅ is input to the inverting input terminal (denoted as in the figure).
Voltages c and d are input. e, , g are the outputs of the comparators, and are input to the IO port in the microcontroller chip shown in FIG. 29.

Let us now consider diving using a portable device with a water depth measurement function configured as described above. A resistance R based on the water quality environment is generated, and the potential level at point a is determined. When the potential level at point a is lower than the potential level at point b (a<b), the output g of the comparator 21
is a low level (hereinafter referred to as "L"; a high level is referred to as "H"). The output of the comparator 22 is "L", and the output e of the comparator 23 is also "L". When b<a<c, g is “L”,
is “L”, is “L”, and e is “H”.

When c<a<d, g is "L", g is "H", and e is also "H". When a>d, both g, and e become "H". As described above, the output to the IO port 9 varies depending on the water quality environment, and the water quality environment level is determined (in this example, there are 4 levels, and by increasing the resistors and comparators that level the water quality environment, the number of levels of the water quality environment level is (can be increased.) Depending on the output status of e, , g to the IO port, the water quality environment value stored in advance in the ROM (Fig. 2, 8) is selected. When a water quality environmental value is selected, the ALU (Fig. 2, 1) is used based on the pressure signal input from the selected signal processing circuit (Fig. 1, 3).
0), the water depth value is calculated and displayed on the display (Fig. 2, 4).
The water depth value is displayed.

〔Effect of the invention〕

As described above, according to the present invention, the water quality environment at the time of diving is determined by the water quality environment level detection means, and the water quality environment value corresponding to the water quality environment level is selected from the water quality environment storage means stored in advance. . Furthermore, the water depth value is calculated and displayed based on the selected water quality environmental value and the pressure detection value of the pressure sensor. Therefore,
Even in water depth gauges that measure water depth by measuring pressure, errors in water depth due to differences in water quality and environment (differences in specific gravity) are automatically corrected, making it possible to obtain a water depth gauge with small errors. As described above, the present invention has great significance.

[Brief explanation of drawings]

Fig. 1: A diagram showing a block diagram of an embodiment of the present invention, Fig. 2: A diagram showing details of a one-chip microcomputer and peripheral circuits, Fig. 3: A cross section of a water quality environment detection means in an embodiment of the present invention. A diagram showing the structure, Figure 4: An enlarged view of the transparent electrode part in Figure 3, Figure 5: A plan view of the transparent electrode part, Figure 6: A diagram showing the structure between the transparent electrodes during diving. FIG. 7 is a diagram showing the circuit configuration of the water quality environment detection means a and the water quality environment value selection means b. DESCRIPTION OF SYMBOLS 1... Pressure sensor, 2... Pressure sensor drive circuit, 3... Signal processing means (circuit), 4... Display section, 5... Water quality environment detection means, 6... Water quality environment value selection means, 7... One chip microcomputer, 8...
ROM (read only memory), 9... IO port (input/output device), 10... ALU (arithmetic operation unit), 11... RAM (random access memory), 12... oscillation circuit, 13... cover glass,
14...Transparent electrode, 14a...Transparent conductive member, 1
4b...transparent insulating member, 15...movement,
16...Exterior case, 17...Insulating member, 18...
...Conductive member, 19... Back cover, 20... Packing, 21... Comparator, 22... Comparator, 23... Comparator.

Claims (1)

[Scope of Claims] 1. A pressure sensor that converts at least water pressure into an electrical signal, a pressure sensor drive circuit that drives the pressure sensor, and a signal processing means that converts the electrical signal from the pressure sensor into a desired measurement signal.
It consists of a display section for displaying water depth values, a power supply, an operation switch for controlling water depth measurement, a case that covers the above elements, and a cover glass that is located above the display section and is integrated with the case. A portable device with a water depth measurement function, which is formed on the cover glass and consists of two transparent electrodes that measure the resistance value generated when water or seawater comes into contact with it, and detects two or more water quality environmental levels. a water quality environment detection means, a water quality environment value storage means in which a water quality environment value corresponding to the water quality environment level is stored in advance, a water quality environment value storage means based on the water quality environment level detected by the water quality environment detection means; Water quality environment selection means for selecting a stored water quality environment value, and water depth value calculation means for calculating a water depth value based on the selected water quality environment value and the pressure detection value measured by the pressure sensor. A portable device with water depth measurement function.