Carbon dioxide concentration detector

Abstract

To provide a carbon dioxide concentration measuring instrument capable of easily grasping the indoor carbon dioxide concentration and the need for ventilation.SOLUTION: A carbon dioxide concentration measuring instrument 1 is a carbon dioxide concentration measuring instrument that notifies the carbon dioxide concentration using lighting. The instrument includes: a sensor 33 for measuring the carbon dioxide concentration; a lighting unit 10 that changes lighting color depending on the carbon dioxide concentration; a power switch 25 for switching on the carbon dioxide concentration measuring instrument 1; and a control unit 31. The control unit 31 is configured so as to, when the time since the power is turned on is less than or equal to a predetermined first time, set the measurement period of the sensor 33 to a first period, and when the time since the power is turned on is larger than the predetermined first time, to set the measurement period of the sensor 33 to a second period longer than the first period.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a carbon dioxide concentration measuring device.

Background Art

[0002] A warning device that measures the carbon dioxide concentration inside a vehicle cabin and outputs a warning to promote ventilation when the carbon dioxide concentration exceeds a threshold value is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the warning device described in Patent Document 1 only promotes ventilation by voice, and there is a problem that the carbon dioxide concentration inside the room cannot be grasped at first glance.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a carbon dioxide concentration measuring device capable of easily grasping the carbon dioxide concentration inside a room and the necessity of ventilation.

Means for Solving the Problems

[0006] To achieve the above object, the carbon dioxide concentration measuring device of the present invention is a carbon dioxide concentration measuring device that notifies the carbon dioxide concentration using illumination, a sensor that measures the carbon dioxide concentration, an illumination unit whose illumination color changes according to the carbon dioxide concentration, a power switch for turning on the power of the carbon dioxide concentration measuring device, and a control unit, When the time after the power is turned on is equal to or less than a first predetermined time, the control unit sets the measurement period of the sensor to a first period, and when the time after the power is turned on is greater than the first predetermined time, the control unit sets the measurement period of the sensor to a second period longer than the first period.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a carbon dioxide concentration measuring device capable of easily grasping the indoor carbon dioxide concentration and the necessity of ventilation.

Brief Description of the Drawings

[0008]

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Modes for Carrying Out the Invention

[0009] An embodiment of the carbon dioxide concentration measuring device of the present invention will be described below. FIGS. 1 to 6 show six views of the carbon dioxide concentration measuring device 1 according to this embodiment, and FIG. 7 shows an exploded perspective view of the carbon dioxide concentration measuring device 1.

[0010] The carbon dioxide concentration measuring device 1 according to this embodiment includes an illumination unit 10 and a base unit 20. The illumination unit 10 is located on the upper surface side of the carbon dioxide concentration measuring device 1, and the base unit 20 is located on the bottom surface side.

[0011] The illumination unit 10 has a diffusion unit 11 and a connection unit 12, and shows an illumination color corresponding to the carbon dioxide concentration measured by a sensor 33 described later.

[0012] The diffusion unit 11 is formed in a cylindrical shape from a transparent or translucent resin, glass, etc., and is formed on the side of the illumination unit 10 opposite to the base unit 20. The diffusion unit 11 is configured to diffuse the light of a light source 32 described later so that it can be visually recognized from above and all around. In addition, in order to uniformly illuminate the light of the light source 32, the diffusion unit 11 may add a diffusing material to the resin to scatter the light, or may form fine irregularities by blasting the surface to scatter the light. Further, the diffusion unit 11 is configured such that the light spreads not only on the upper surface but also on the side surface by ensuring the height for the spread of the light from the light source 32. Thereby, the carbon dioxide concentration measuring device 1 can easily grasp its illumination color even when it is placed on a table and visually recognized from above or visually recognized from a distance.

[0013] The connection unit 12 is formed on the side of the base unit 20 of the illumination unit 10 and is configured to be connectable to the base unit 20.

[0014] The base unit 20 is formed in a cylindrical shape from resin, and has a leg portion 21, a connection portion 22, a display portion 23, a ventilation port 24, a power switch 25, a through hole 26, a rib 27, a battery storage portion 28, and a power supply hole 29, and stores a control board 30 described later inside the base unit 20.

[0015] The foot portion 21 is formed on the side opposite to the lighting portion 10 of the base portion 20, and is configured to maintain a space between the carbon dioxide concentration measuring device 1 and the installation location. Thereby, the carbon dioxide concentration measuring device 1 can take in indoor air through the ventilation opening 24, and prevent moisture passing along the side surface of the base portion 20 from entering the interior through the ventilation opening 24.

[0016] The connecting portion 22 is formed on the side opposite to the lighting portion 10 of the base portion 20, and is configured to be connectable to the lighting portion 10. For example, a hook structure is used for the connecting portion 12 and the connecting portion 22.

[0017] The display portion 23 is provided on the side surface of the base portion 20, and is configured by making holes for the number of indicators 34 so that the light of the indicator 34 described later can be visually recognized from the front of the carbon dioxide concentration measuring device 1. Note that the display portion 23 may have a label attached thereto indicating the correspondence between the illumination colors of the lighting portion 10 and the indicator 34 and the carbon dioxide concentration.

[0018] A pair of ventilation openings 24 are formed on the side opposite to the lighting portion 10 of the base portion 20, with one of them 24A functioning as an air intake port and the other 24B functioning as an air outlet port. Note that the functions of one 24A and the other 24B of the ventilation opening 24 may be opposite to those described above.

[0019] The power switch 25 is provided on the side opposite to the lighting portion 10 of the base portion 20, and is used to turn the carbon dioxide concentration measuring device 1 on / off.

[0020] The through hole 26 is formed on the side of the lighting portion 10 of the base portion 20, and is configured to have a diameter sufficient to deliver the light of the light source 32 to the diffusion portion 11.

[0021] The rib 27 is a wall formed around the through hole 26, and even if water enters from the gap between the connecting portion 12 of the lighting unit 10 and the connecting portion 22 of the base portion 20, it prevents the water from reaching the control board 30 through the through hole 26. Thereby, the carbon dioxide concentration measuring device 1 can achieve waterproofing for daily use without using an airtight member such as an O-ring, and the manufacturing cost can be reduced by reducing the number of parts and facilitating assembly. Further, the carbon dioxide concentration measuring device 1 can discharge the water vapor generated when the intruded water evaporates to the outside of the carbon dioxide concentration measuring device 1 through the through hole 26 and the vent hole 24, preventing condensation inside the lighting unit 10. Also, the rib 27 is preferably configured to have a height that does not block the light of the light source 32 passing through the through hole 26.

[0022] The battery storage portion 28 is composed of a battery holder 28A and a battery lid 28B formed in the base portion 20, and is configured to store a battery and supply its power to the carbon dioxide concentration measuring device 1.

[0023] The power supply hole 29 is a hole opened in the back surface of the base portion 20 so that it can be externally connected to a power supply portion 39 described later.

[0024] The control board 30 includes a control portion 31, a light source 32, a sensor 33, an indicator 34, and a power supply portion 39. The control board 30 is configured in a disk shape in order to be housed in the base portion 20 and to bring the indicator 34 and the power supply portion 39 closer to the side surface of the base portion 20.

[0025] For the control portion 31, for example, a microcomputer having an arithmetic circuit, a memory circuit, a timing circuit, a communication circuit, a power control circuit, etc. is applied, and it is possible to control the functions of the carbon dioxide concentration measuring device 1.

[0026] The light source 32 is configured to include a red LED, a blue LED, and a green LED, and emits light in an arbitrary color under the control of the control portion 31. The light source 32 is mounted on the lighting unit 10 side of the control board 30. The light source 32 emits light in a first color (e.g., blue) when the carbon dioxide concentration is in a first range (e.g., 400 ppm or more and less than 1000 ppm (normal; ventilation not required)), emits light in a second color (e.g., red) when in a second range (e.g., 2000 ppm or more (ventilation; ventilation required)), emits light in a third color (e.g., yellow) when in a third range (e.g., 1000 ppm or more and less than 2000 ppm (caution; ventilation recommended)), and notifies the carbon dioxide concentration in three levels according to the illumination color of the lighting unit 10. Note that, in addition to the three levels of notification, it may also be in two levels of normal and ventilation or four levels or more. In addition, the carbon dioxide concentration measuring device 1 mounts a buzzer (not shown) on the control board 30, and may add an audible notification when the measured carbon dioxide concentration changes to another range (e.g., from the first range to the second range).

[0027] The sensor 33 is, for example, a gas sensor using a non-dispersive infrared (NDIR) method or a photoacoustic spectroscopy (PAS) method. It measures the indoor air taken in from the ventilation port 24 and transmits the measured carbon dioxide concentration to the control unit 31. The sensor 33 is mounted on the side of the control board 30 opposite to the lighting unit 10, is close to at least one of the ventilation ports 24, and is arranged on a straight line between one 24A and the other 24B of the ventilation ports 24. Thereby, in the carbon dioxide concentration measuring device 1, the sensor 33 is arranged in the flow path of the taken-in air, and the indoor carbon dioxide concentration can be measured more accurately.

[0028] The indicator 34 includes a first LED 34A that emits light in the first color and indicates that the carbon dioxide concentration is in the first range (normal; ventilation not required), a second LED 34B that emits light in the second color and indicates that the carbon dioxide concentration is in the second range (ventilation; ventilation required), and a third LED 34C that emits light in the third color and indicates that the carbon dioxide concentration is in the third range (caution; ventilation recommended). Note that the indicator 34 may increase or decrease the number of LEDs so as to match the notification level of the light source 32. The indicator 34 uses a side-emitting type LED, is mounted in a direction orthogonal to the lighting unit 10 of the control board 30, and is mounted in a direction opposite to the power supply unit 39.

[0029] The power supply unit 39 is a connector configured to be connectable to a power cable or a USB cable, and supplies power to the carbon dioxide concentration measuring device 1. Note that the carbon dioxide concentration measuring device 1 may be supplied with power from a battery when not supplied with power from the power supply unit 39. The power supply unit 39 is mounted in a direction orthogonal to the lighting unit 10 of the control board 30 and in a direction opposite to the indicator 34.

[0030] As a result, the carbon dioxide concentration measuring device 1 can mount the light source 32, the sensor 33, the indicator 34, and the power supply unit 39 on a single control board 30, reducing the number of components and the cost. Note that when the control board 30 is incorporated into the carbon dioxide concentration measuring device 1, the indicator 34 is arranged on the front, the power supply unit 39 is arranged on the back, the light source 32 is arranged on the upper surface, and the sensor 33 is arranged on the bottom surface.

[0031] Refer to FIG. 8. FIG. 8 is a flowchart showing the control of the carbon dioxide concentration measuring device 1. The carbon dioxide concentration measuring device 1 defines a first predetermined time and a second predetermined time in advance in the control unit 31, and the second predetermined time is set shorter than the first predetermined time.

[0032] In step S1, the control unit 31 turns on the power of the carbon dioxide concentration measuring device 1 by pressing the power switch 25.

[0033] In step S2, the control unit 31 receives the carbon dioxide concentration measured by the sensor 33.

[0034] In step S3, the control unit 31 determines whether a second predetermined time has elapsed since the power was turned on. If it is determined that the second predetermined time has elapsed (Yes), the process proceeds to step S11. If it is determined that the second predetermined time has not elapsed (No), the process proceeds to step S4. The second predetermined time is the time until the carbon dioxide concentration detection accuracy of the sensor 33 stabilizes after the power is turned on, and can be appropriately set according to the sensor element to be used.

[0035] In step S4, the control unit 31 turns on all the LEDs of the light source 32 and lights them in a color different from the color indicating the carbon dioxide concentration. For example, when the light source 32 includes a red LED, a blue LED, and a green LED, the illumination color becomes white. Thereby, the carbon dioxide concentration measuring device 1 prevents the presentation of a carbon dioxide concentration with low reliability until the carbon dioxide detection accuracy of the sensor 33 stabilizes after the power is turned on. Also, the carbon dioxide concentration measuring device 1 can check whether there is a defect in the light source 32 by turning on all the LEDs of the light source 32, and can also serve as a shipping inspection.

[0036] In step S5, the control unit 31 determines whether the power switch 25 has been pressed. If it is determined that the power switch 25 has been pressed (Yes), the process proceeds to step S6. If it is determined that the power switch 25 has been pressed (No), the process proceeds to step S2.

[0037] In step S6, the control unit 31 turns off the power of the carbon dioxide concentration measuring device 1.

[0038] In step S11, the control unit 31 determines whether a first predetermined time has elapsed since the power was turned on. If it is determined that the first predetermined time has elapsed (Yes), the process proceeds to step S12. If it is determined that the first predetermined time has not elapsed (No), the process proceeds to step S13.

[0039] In step S12, the control unit 31 sets the measurement period of the sensor 33 to a first period (measurement interval: short). For example, the sensor 33 measures the carbon dioxide concentration once every 5 seconds and transmits it to the control unit 31.

[0040] In step S13, the control unit 31 sets the measurement period of the sensor 33 to a second period (measurement interval: long) that is longer than the first period. For example, the sensor 33 measures the carbon dioxide concentration once every 30 seconds and transmits it to the control unit 31.

[0041] In step S14, the control unit 31 turns on the light source 32 and the indicator 34 according to the carbon dioxide concentration received from the sensor 33. Thereby, the carbon dioxide concentration measuring device 1 can quickly reflect the measurement result of the sensor 33 on the lighting unit 10 in a situation where the user after turning on the power wants to know the carbon dioxide concentration in the room. Also, the carbon dioxide concentration measuring device 1 reduces power consumption by reducing the measurement frequency of the sensor 33 after a certain period of time has passed since turning on the power, and in particular, when the carbon dioxide concentration measuring device 1 is powered by a battery, the operating time of the carbon dioxide concentration measuring device 1 can be extended.

[0042] Refer to FIG. 9. FIG. 9 is a flowchart showing a modified example of the control of the carbon dioxide concentration measuring device 1.

[0043] In step S1, the control unit 31 turns on the power of the carbon dioxide concentration measuring device 1 by pressing the power switch 25.

[0044] In step S21, the control unit 31 determines whether the inspection pins of the control board 30 are short-circuited. If it is determined that the inspection pins are short-circuited (Yes), the process proceeds to step S22. If it is determined that the inspection pins are not short-circuited (No), the process proceeds to step S2, and the same control as in FIG. 8 is performed.

[0045] In step S22, the control unit 31 shifts to a shipping inspection mode different from the normal operation mode.

[0046] In step S23, the control unit 31 outputs the numerical value of the carbon dioxide concentration measured by the sensor 33 via serial communication (e.g., UART: Universal Asynchronous Receiver / Transmitter).

[0047] In step S24, the control unit 31 determines whether the inspection pin of the control board 30 is released. If it is determined that the inspection pin is released (Yes), the process proceeds to step S25. If it is determined that the inspection pin is not released (No), the process proceeds to step S22.

[0048] In step S25, the control unit 31 resets and restarts the control unit 31. Thereby, at the time of shipment inspection, the carbon dioxide concentration measuring device 1 can calibrate the sensor 33 based on detailed numerical values by short-circuiting the inspection pins, and at the time of product shipment, by releasing the inspection pins, unnecessary information output can be suppressed and the load on the control unit 31 can be reduced.

[0049] The embodiments described above have the following effects.

[0050] The carbon dioxide concentration measuring device 1 is a carbon dioxide concentration measuring device that notifies the carbon dioxide concentration using illumination, a sensor 33 for measuring the carbon dioxide concentration, an illumination unit 10 whose illumination color changes according to the carbon dioxide concentration, a power switch 25 for turning on the power of the carbon dioxide concentration measuring device 1, and a control unit 31, The control unit 31 sets the measurement period of the sensor 33 to a first period when the time after the power is turned on is equal to or less than a first predetermined time, and sets the measurement period of the sensor 33 to a second period longer than the first period when the time after the power is turned on is greater than the first predetermined time.

[0051] The carbon dioxide concentration detector 1 can quickly reflect the measurement result of the sensor 33 to the lighting unit 10 in a situation where the user wants to know the indoor carbon dioxide concentration after the power is turned on. In addition, the carbon dioxide concentration detector 1 reduces power consumption by reducing the measurement frequency of the sensor 33 after a certain period of time has elapsed since the power was turned on, and can extend the operating time of the carbon dioxide concentration detector 1, especially when the carbon dioxide concentration detector 1 is powered by a battery.

[0052] In the carbon dioxide concentration detector 1, the lighting unit 10 has at least the first lighting color indicating that the carbon dioxide concentration is within the normal range and the second lighting color indicating that the carbon dioxide concentration is in the range where ventilation is required. When the time elapsed since the power was turned on is a second predetermined time shorter than the first predetermined time, the control unit 31 controls the lighting unit 10 to exhibit the lighting color different from the first and the second.

[0053] The carbon dioxide concentration detector 1 prevents the presentation of a carbon dioxide concentration with low reliability until the carbon dioxide detection accuracy of the sensor 33 stabilizes after the power is turned on.

[0054] In the carbon dioxide concentration detector 1, the lighting unit 10 is illuminated by a light source 32 having a red LED, a blue LED, and a green LED. When the time elapsed since the power was turned on is the second predetermined time, the control unit 31 controls all of the red LED, the blue LED, and the green LED of the light source 32 to be lit so that the lighting color of the lighting unit 10 shows white.

[0055] The carbon dioxide concentration detector 1 can confirm whether there is a defect in the light source 32 by lighting all the LEDs of the light source 32, and can also serve as a shipping inspection.

[0056] In the carbon dioxide concentration detector 1, the control unit 31 is mounted on a control board 30 having inspection pins. When the power is turned on, it is determined whether the test pin is short-circuited. If it is determined that there is a short circuit, the carbon dioxide concentration is output by serial communication.

[0057] During the shipping inspection, the carbon dioxide concentration measuring device 1 can calibrate the sensor 33 based on detailed numerical values by short-circuiting the test pins. When the product is shipped, by releasing the test pins, unnecessary information output can be suppressed and the load on the control unit 31 can be reduced.

[0058] In addition, in the above-described embodiment, the carbon dioxide concentration measuring device 1 may be used for measuring the carbon dioxide concentration associated with the use of the cooking appliance and / or the heating appliance and presenting the necessity of ventilation.

[0059] The present invention is not limited by the above embodiments and drawings. Within the scope of not changing the gist of the present invention, it is possible to make appropriate changes (including deletion of components) as needed.

Explanation of Reference Numerals

[0060] 1 Carbon dioxide concentration measuring device 10 Lighting unit 11 Diffusion unit 12 Connecting unit 20 Base unit 21 Legs 22 Connecting unit 23 Display unit 24 Ventilation opening 26 Through hole 27 Rib 30 Control board 31 Control unit 32 Light source 33 Sensor 34 Indicator 39 Power supply unit

Claims

1. A carbon dioxide concentration measuring device that notifies the carbon dioxide concentration using lighting, comprising: a sensor that measures the carbon dioxide concentration; a lighting unit whose lighting color changes according to the carbon dioxide concentration; a power switch for turning on the power of the carbon dioxide concentration measuring device; a control unit, and when the time elapsed since the power was turned on is equal to or less than a first predetermined time, the control unit sets the measurement cycle of the sensor to a first cycle, and when the time elapsed since the power was turned on is greater than the first predetermined time, the control unit sets the measurement cycle of the sensor to a second cycle longer than the first cycle. A carbon dioxide concentration measuring device.

2. The lighting unit has at least a first lighting color indicating that the carbon dioxide concentration is within a normal range and a second lighting color indicating that the carbon dioxide concentration is in a range where ventilation is required, and when the time elapsed since the power was turned on is equal to or less than a second predetermined time shorter than the first predetermined time, the control unit controls the lighting unit to exhibit a lighting color different from the first and the second. The carbon dioxide concentration measuring device according to Claim 1.

3. The lighting unit is illuminated by a light source having a red LED, a blue LED, and a green LED, and when the time elapsed since the power was turned on is equal to or less than the second predetermined time, the control unit turns on all of the red LED, the blue LED, and the green LED of the light source to control the lighting color of the lighting unit to indicate white. The carbon dioxide concentration measuring device according to Claim 2.

4. The control unit is mounted on a control board having a test pin, determines whether the test pin is short-circuited when the power is turned on, and when it is determined that the test pin is short-circuited, outputs the carbon dioxide concentration by serial communication. The carbon dioxide concentration measuring device according to any one of Claims 1 to 3.

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