Dust sensor that controls the amount of light emission by controlling the light emission current

Abstract

The utility model discloses a dust detector through control luminous current to control luminous quantity, including setting in the detection area's luminous element, light receiving element and signal amplification circuit, control and detect light emission and light receiving signal's microcontroller and luminous light quantity control circuit, luminous light quantity control circuit is in series by electronic switch, resistance R1 and capacitor C1 composition, one end of electronic switch connects resistance R1, and the other end connects power supply, one end of capacitor C1 connects resistance R1, and the other end ground connection, the trigger control end of electronic switch connects microcontroller, the connecting node of resistance R1 and capacitor C1 is through resistance R3 and connects luminous element, and luminous element drive circuit is controlled and is connected in microcontroller. The utility model dust sensor can control luminous element luminous light quantity, can improve dust sensor measurement result's accuracy and reliability through the accurate control to luminous element's luminous quantity.

Description

Technical Field

[0001] This utility model relates to a dust sensor, and more particularly to a dust detector that controls the amount of light emitted by controlling the luminous current. Background Technology

[0002] Dust sensors are widely used in industrial production, environmental monitoring, and building safety. They detect the content / concentration of particulate matter in the environment by detecting changes in the electrical signal caused by dust or smoke within a relatively enclosed detection area. The dust sensor's control unit (MCU) drives a light-emitting element to emit light as the detection light source through a light-emitting element driving circuit. The detection light source is located on one side of the detection chamber, which is used to shield external light sources, while a light-receiving element is located on the other side.

[0003] In practical applications, the light emission (luminous intensity) control of the light-emitting element in a dust sensor directly affects the detection results. The accuracy of light emission / intensity control directly impacts the sensor's detection precision and sensitivity for dust particles. Improper light emission control, such as excessively strong or weak light, can lead to unstable or distorted data output from the dust sensor, thus affecting the final detection results. Therefore, in practical applications, it is necessary to ensure that the light emission (luminous intensity) control of the dust sensor is at its optimal state to improve detection accuracy and reliability.

[0004] Current dust sensors (such as) Figure 1 As shown, there are few or no dedicated control circuits for controlling the amount of light emitted by the light-emitting element, making it impossible to adjust the amount / intensity of light emitted by the light-emitting element, and making it difficult to ensure the accuracy of the dust sensor measurement results. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by proposing a dust sensor that controls the amount of light emitted by controlling the luminous current. This allows for control of the light quantity / intensity of the luminous element, thereby improving the accuracy of the dust sensor's measurement results through precise control of the light quantity / intensity.

[0006] A dust sensor that controls the amount of light emitted by controlling the luminous current includes a light-emitting element disposed in the detection area, a light-receiving element, an amplification circuit for amplifying the photocurrent signal generated in the light-receiving element, a microcontroller for controlling and detecting the light emission and light reception signals, and a light emission control circuit. The light emission control circuit consists of an electronic switch, a resistor R1, and a capacitor C1 connected in series. The output terminal of the electronic switch is connected to the resistor R1, and the input terminal is connected to a power supply. One end of the capacitor C1 is connected to the resistor R1, and the other end is grounded. The trigger control terminal of the electronic switch is connected to the microcontroller. The connection node of the resistor R1 and the capacitor C1 is connected to the light-emitting element through a resistor R3. The light-emitting element driving circuit is controlled and connected to the microcontroller.

[0007] The dust sensor uses a MOS transistor as its electronic switch. The source terminal of the MOS transistor is connected to a power supply, the drain terminal of the MOS transistor is connected to one end of a resistor R1, the other end of the resistor R1 is connected to a capacitor C1, and the gate terminal of the MOS transistor is connected to a microcontroller.

[0008] The dust sensor described above uses a bipolar transistor as its electronic switch. The emitter of the bipolar transistor is connected to a power supply, and its collector terminal is connected to one end of a resistor R1. The other end of the resistor R1 is connected to a capacitor C1, and the base terminal of the bipolar transistor is connected to a microcontroller through a resistor R2.

[0009] The dust sensor described above uses a MOS transistor switching circuit to drive the light-emitting element. One end of resistor R3 is connected to the connection node of resistor R1 and capacitor C1 in the light emission control circuit, and the other end of resistor R3 is connected to the light-emitting element. The light-emitting element is connected to the source of the MOS transistor, the drain of the MOS transistor is grounded, and the gate of the MOS transistor is controlled to be connected to the microcontroller.

[0010] The dust sensor and the light-emitting element are adjacent to a temperature sensor, which is a digital temperature sensor, and the output signal of the temperature sensor is connected to a microcontroller.

[0011] 1. This utility model of a dust sensor includes a light emission quantity / intensity control circuit for a light-emitting element. By controlling the emission current of the light-emitting element, the accuracy of the dust sensor's measurement results is improved. When storing charge in the charge supply node, resistor R1 can optimize the charge storage time. When resistor R1 increases, the charge accumulation time is extended, thus allowing for fine adjustment of the accumulated charge amount. This enables high-precision adjustment of the current applied to the light-emitting element, i.e., the emission quantity.

[0012] 2. This dust sensor allows for easy and precise adjustment / control of the current to the light-emitting element by controlling the ON / OFF state of the IO terminals in the MCU. It is easy to implement and has low circuit cost. Furthermore, by OFF the transistor during light emission, power supply noise when providing the light-emitting current can be reduced. Attached Figure Description

[0013] Figure 1 The diagram shown is a schematic of a dust sensor in the prior art. Figure 2 The diagram shown is a schematic diagram of the dust sensor of this utility model. Figure 3 The diagram shown is an electrical schematic of one embodiment of the dust sensor of this utility model. Figure 4 The diagram shown is an electrical schematic diagram of a second embodiment of the dust sensor of this utility model. Figure 5 The diagram shown is an electrical schematic of an embodiment of the dust sensor of this invention that employs temperature compensation. Detailed Implementation

[0014] To make the technical concept and advantages of this utility model more clearly understood, the technical solution of this utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are merely preferred embodiments for explaining and illustrating this utility model, and should not be considered as, nor constitute a limitation on, the scope of patent protection claimed for this utility model. Example

[0015] See Figure 3 , Figure 4 This utility model dust sensor includes a light-emitting element, a light-receiving element disposed in the detection area, an amplification circuit for amplifying the photocurrent signal generated in the light-receiving element, and a microcontroller (hereinafter referred to as "MCU") for controlling and detecting the light emission and light reception signals. See [link to relevant documentation]. Figure 1 , Figure 2 This utility model ( Figure 2 ) and existing technology ( Figure 1 The difference lies in that it also includes a light emission control circuit; the light emission control circuit consists of an electronic switch, a resistor R1 and a capacitor C1 connected in series. The output terminal of the electronic switch is connected to the resistor R1, and the input terminal is connected to the power supply. One end of the capacitor C1 is connected to the resistor R1, and the other end is grounded. The trigger control terminal of the electronic switch is connected to the microcontroller. The connection node of the resistor R1 and the capacitor C1 (the charge supply node N1 of the light-emitting element) is connected to the light-emitting element through the resistor R3. The driving circuit of the light-emitting element is controlled and connected to the microcontroller.

[0016] By adjusting the illumination amount through a light intensity control circuit controlled by a microcontroller (MCU), a stable amount of light can be provided to the dust sensor / light-emitting element, helping to ensure the accuracy and stability of the measurement results. The amount of light / illuminance can be adjusted through the MCU program, making it relatively easy to adjust.

[0017] Capacitor C1 is connected between the charge supply node N1, which allows current to flow through the light-emitting element, and GND. The amount of light emitted is controlled by adjusting the amount of charge at the charge supply node (N1). By accumulating charge in the capacitor to allow current to flow through the light-emitting element and applying the charge to the light-emitting element, the amount of light emitted by the light-emitting element can be controlled by adjusting the amount of charge.

[0018] When storing charge in a charge supply node, a resistor (R1) can optimize the charge storage time. As the resistance R1 increases, the charge accumulation time is prolonged, thus allowing for fine adjustment of the accumulated charge amount. This enables highly precise regulation of the current applied to the light-emitting element, i.e., the amount of light emitted. Example

[0019] See Figure 3 In this embodiment, the dust sensor uses a MOS transistor as its electronic switch. The source terminal of the MOS transistor is connected to a power supply, and the drain terminal is connected to one end of a resistor R1. The other end of the resistor R1 is connected to a capacitor C1, and the gate terminal of the MOS transistor is connected to a microcontroller. The on / off state of the light emission control circuit is controlled via the MCU's I / O terminals. Example

[0020] See Figure 4 In this embodiment, the dust sensor uses a bipolar transistor as its electronic switch. The emitter of the bipolar transistor is connected to a power supply, and its collector terminal is connected to one end of a resistor R1. The other end of the resistor R1 is connected to a capacitor C1. The base terminal of the bipolar transistor is connected to a microcontroller through a resistor R2 to control the amount of light emitted.

[0021] By controlling the ON / OFF timing of the I / O terminals in the MCU, the light intensity of the light-emitting element can be easily and precisely adjusted. Furthermore, by turning the transistor OFF during light emission, power supply noise when providing the light-emitting current can be reduced.

[0022] like Figure 3 , Figure 4As shown, the driving circuit of the light-emitting element adopts a CPMOS / PMOS transistor switching circuit. One end of the resistor R3 is connected to the connection node (charge supply node N1) of the resistor R1 and capacitor C1 in the light emission control circuit. The other end of the resistor R3 is connected to the light-emitting element. The light-emitting element is connected to the source of the MOS transistor. The drain of the MOS transistor is grounded. The gate of the MOS transistor is controlled to be connected to the microcontroller.

[0023] Figure 5 The diagram shown is an electrical schematic of an embodiment of the dust sensor of this invention using temperature compensation; compared with Embodiment 2 / Figure 3 Compared to the previous method, a temperature sensor is added. A temperature sensor is located adjacent to the light-emitting element in the detection area. This temperature sensor is a digital temperature sensor, and its output signal is connected to the microcontroller.

[0024] Since the light emission of the light-emitting element decreases at high temperatures, temperature compensation can be achieved by increasing the current flowing through the light-emitting element at high temperatures, thereby expanding the operating temperature range of the dust sensor. The operating temperature of the light-emitting element is detected using a built-in temperature sensor in the MCU or a separately provided temperature sensor, and the MCU can perform temperature compensation by controlling the amount of light emitted.

[0025] Figure 5 The diagram shows an example of the timing and waveform of the light emission control circuit used in the dust sensor of this invention. As shown in Case 1 and Case 2, this invention allows adjustment of the light emission element current I_LED by adjusting the conduction time of the light emission control signal CTL2. In the illustrated cases, the light emission element current value is greater in Case 1 than in Case 2.

Claims

1. A dust sensor that controls the amount of light emitted by controlling the luminous current, comprising a light-emitting element disposed in a detection area, a light-receiving element, and an amplification circuit for amplifying the photocurrent signal generated in the light-receiving element, and a microcontroller for controlling and detecting the light emission and light reception signals, characterized in that: It also includes a light emission control circuit; the light emission control circuit consists of an electronic switch, a resistor R1 and a capacitor C1 connected in series, the connection node of the resistor R1 and the capacitor C1 is connected to the light emission element through a resistor R3, and the trigger control terminal of the electronic switch connected to the power supply is connected to the microcontroller.

2. The dust sensor according to claim 1, characterized in that: The output terminal of the electronic switch is connected to resistor R1, one end of capacitor C1 is connected to resistor R1, and the other end is grounded.

3. The dust sensor according to claim 1 or 2, characterized in that: The electronic switch uses a MOS transistor. The source terminal of the MOS transistor is connected to the power supply, the drain terminal of the MOS transistor is connected to one end of a resistor R1, the other end of the resistor R1 is connected to a capacitor C1, and the gate terminal of the MOS transistor is connected to a microcontroller.

4. The dust sensor according to claim 3, characterized in that: The driving circuit of the light-emitting element adopts a MOS transistor switch. One end of resistor R3 is connected to the connection node of resistor R1 and capacitor C1 in the light emission control circuit, and the other end of resistor R3 is connected to the light-emitting element. The light-emitting element is connected to the source of the MOS transistor, the drain of the MOS transistor is grounded, and the gate of the MOS transistor is controlled to be connected to the microcontroller.

5. The dust sensor according to claim 1 or 2, characterized in that: The electronic switch uses a bipolar transistor. The emitter of the bipolar transistor is connected to the power supply, and its collector terminal is connected to one end of a resistor R1. The other end of the resistor R1 is connected to a capacitor C1. The base terminal of the bipolar transistor is connected to a microcontroller through a resistor R2.

6. The dust sensor according to claim 5, characterized in that: The driving circuit of the light-emitting element adopts a MOS transistor switch. One end of resistor R3 is connected to the connection node of resistor R1 and capacitor C1 in the light emission control circuit, and the other end of resistor R3 is connected to the light-emitting element. The light-emitting element is connected to the source of the MOS transistor, the drain of the MOS transistor is grounded, and the gate of the MOS transistor is controlled to be connected to the microcontroller.

7. The dust sensor according to claim 1, 2, 4 or 6, characterized in that: A temperature sensor is provided adjacent to the light-emitting element. The temperature sensor is a digital temperature sensor, and the output signal of the temperature sensor is connected to the microcontroller.

8. The dust sensor according to claim 3, characterized in that: A temperature sensor is provided adjacent to the light-emitting element. The temperature sensor is a digital temperature sensor, and the output signal of the temperature sensor is connected to the microcontroller.

9. The dust sensor according to claim 5, characterized in that: A temperature sensor is provided adjacent to the light-emitting element. The temperature sensor is a digital temperature sensor, and the output signal of the temperature sensor is connected to the microcontroller.

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