RU211749U1 - Dust sensor - Google Patents

Abstract

The utility model relates to the technical field of measuring instruments, in particular, to sensors for measuring the concentration of dust in the air and can be used in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them. The dust sensor contains an infrared emitter 5 with a driver 8 and a photodetector 6, focused in the area of measurement of dust concentration 12, connected respectively through a transistor switch 9 and a signal amplifier 7 with a microcontroller 11 with a built-in analog-to-digital converter 10 and interface input and output, and a power supply 22 microcontroller 11 is equipped with an interface bus 4, including a positive DALI + wire and a negative DALI- wire, combined with a circuit ground, and the microcontroller 11 is equipped with output 15 and input 14 transistor switches, of which the input switch 14 is made on a bipolar npn transistor 17, the collector of which is connected with the interface input of the microcontroller 11 with the built-in pull-up resistor 13 turned on, the emitter is connected to the wire of the DALI interface bus 4, while the emitter junction of the transistor 17 is shunted by a resistor connected between the emitter and the base, and the base is connected through a series-connected current-limiting resistor and a stabilizer litron with a DALI+ wire of the interface bus 4, and the output switch 15 is made on an n-type field effect transistor 16, the drain of which is connected to the DALI+ wire of the interface bus 4, the source is connected to the wire of the DALI- interface bus 4, and the gate is connected to the interface output of the microcontroller 11. EFFECT: enabling the use of a dust sensor in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them. 1 ill.

Description

The utility model relates to the technical field of measuring instruments, in particular to sensors for measuring the concentration of dust in the air and can be used in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them.

To measure the concentration of dust in the air, the most widely used optical dust sensors, consisting of a box with an optical system, an infrared emitter and a photodetector, installed at an angle to each other and focused in the area where dust enters from the outside, the concentration of which is measured by highlighting dust particles and recording light reflected from them.

A dust sensor is known, which contains an infrared emitter with optical receivers of reflected and attenuated radiation, optical receivers are located in the same plane with the emitter, while the sensor is placed in a housing and has a built-in computing device that outputs readings to an indicator located in a stationary or portable device (patent RF No. 186970 U1, published on February 12, 2019).

The mentioned sensor is quite functional and easy to maintain, however, it has a significant drawback - a limited scope, since it cannot be integrated into distributed digital environmental monitoring systems due to the lack of an appropriate external interface.

Known dust sensor, including installed at an angle to each other and focused in the zone of measurement of dust concentration infrared emitter and photodetector, transimpedance signal amplifier from the photodetector with an active filter, the analog input of which is connected to the analog output of the photodetector, and an interface with analog inputs and outputs (www. .ti.com [Electronic resource] - Access mode: https://www.ti.com/lit/ug/tidub65c/tidub65c.pdf?ts=1640085582188&ref_url=https%253A%252F%252Fwww.google.ru%252F , free - (22.02.2022).

The mentioned analog is quite functional and easy to maintain, however, it has a significant drawback - a limited scope, since it cannot be integrated into distributed digital environmental monitoring systems using, for example, the DALI protocol, since it has an analog interface.

The closest to the claimed - the prototype - is a dust sensor, including an infrared emitter with a driver and a photodetector focused in the dust concentration measurement zone, connected respectively through a signal amplifier and a transistor switch with a microcontroller with a built-in analog-to-digital converter, a DC power supply and an interface formed corresponding inputs and outputs of the microprocessor that gives indications to the indicator and receives commands from the remote control located in a stationary or portable device (www.ti.com [Electronic resource]. - Access mode: https://global.sharp/products/device/lineup /data/pdf/datasheet/gp2y1010au_appl_e.pdf, free - (02/22/2022).

The mentioned prototype is quite functional and easy to manufacture and maintain, however, it has a significant drawback - it cannot be integrated into distributed digital environmental monitoring systems based on lighting objects (road, urban, rural, etc.) using the DALI profile protocol for them. due to the lack of an appropriate interface. Informational: such a distributed digital monitoring system was implemented as part of the KULON program of Sandraks LLC (www.kulon.su [Electronic resource]. - Access mode: https://www.kulon.su/catalog/products-QULON/, free - (03/10/2022) The advantages of using a lighting control system for environmental monitoring include its actual presence (there is no need to create a new network), a very wide and dense branching, the convenience of placing the corresponding sensors on supports, brackets, panels, etc. lighting, its reliability and noise immunity.

The technical problem is to eliminate the noted shortcomings of the known technical solutions.

The technical result consists in enabling the use of a dust sensor in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them.

The problem is solved, and the claimed technical result is achieved by the fact that a dust sensor containing an infrared emitter with a driver and a photodetector focused in the dust concentration measurement zone, connected respectively through a transistor switch and a signal amplifier with a microcontroller with a built-in analog-to-digital converter and interface input and output, and the power supply of the microcontroller, is equipped with an interface bus, including a positive DALI + wire and a negative DALI- wire, combined with a circuit ground, and the microcontroller is equipped with input and output transistor switches, of which the input switch is made on a bipolar n-p-n transistor, the collector of which is connected with an interface input of the microcontroller with a built-in pull-up resistor enabled, the emitter is connected to the wire of the DALI interface bus, while the emitter junction of the transistor is shunted by a resistor connected between the emitter and the base, and the base is connected through series-connected current limiters pull-down resistor and zener diode with DALI+ wire of the interface bus, and the output switch is made on an n-type field effect transistor, the drain of which is connected to the DALI+ wire of the interface bus, the source is connected to the DALI-interface bus wire, and the gate is connected to the interface output of the microcontroller.

The utility model is illustrated by a drawing, which shows a schematic diagram of the claimed dust sensor.

Numerical positions in the drawing mean the following:

1 - DALI+ interface wire;

2 - interface wire DALI-, combined with circuit ground GND;

3 - circuit ground (GND);

4 - interface bus;

5 - infrared emitter;

6 - photodetector;

7 - signal amplifier from the photodetector;

8 - infrared emitter driver;

9 - transistor key;

10 - analog-to-digital converter (ADC);

11 - microcontroller;

12 - dust concentration measurement zone;

13 - built-in pull-up resistor (PULL-UP) of the microcontroller input;

14 - input transistor key;

15 - output transistor key;

16 - n-type field effect transistor;

17 - bipolar n-p-n transistor;

18 - resistor shunting the emitter junction of a bipolar n-p-n transistor;

19 - current limiting resistor;

20 - zener diode;

21 - zero-level fixing resistor;

22 - power supply;

23 - power outlets for dust sensor components.

In accordance with the claimed utility model, the dust sensor contains focused in the zone of measurement of the concentration of dust 12 (as in the prototype, the area of dust entry is a box permeable to the dust-air mixture) infrared emitter 5 with a driver 8 and a photodetector 6 (in the drawing, the relative orientation is conditionally shown arrows). The infrared emitter 5 through the driver 8 and the photodetector 6 through the signal amplifier 7 and the transistor switch 9 are connected to the microcontroller 11, equipped with an analog-to-digital converter (ADC) 10. In this part, the claimed technical solution completely coincides with the prototype. Unlike the prototype, the DALI interface with bus 4 was used as an interface, including the first 1 interface wire DALI+ and the second 2 interface wire DALI-, combined with the circuit ground GND. The power supply 22 of the microcontroller 11 has positive and GND (negative/circuit ground/housing) outputs that feed the microcontroller 11, in addition, the power supply 22 may provide power taps for 23 individual dust sensor components. The microcontroller 11 is provided with interface input and output and output 15 and input 14 transistor switches interacting with them. The input key 14 is made on a bipolar n-p-n transistor 17, the emitter (hereinafter referred to as transistor elements correspond to their standard symbols on the symbols used in the presented drawing) of which is connected to the second 2 wire of the bus 4, the collector is connected to the interface input of the microcontroller 11 with the built-in pull-up PULL-UP resistor 13, and the emitter is connected to the second wire 2 of the mentioned bus 4, while the emitter junction of the transistor 17 is shunted by a resistor 18 connected between the emitter and the base, and the base is connected through a series-connected current-limiting resistor 19 and a zener diode 20 (information: installation sequence resistor 19 and zener diode 20 one after another is not significant) with the first wire 1 of the mentioned bus 4. The output switch 15 is made on an n-type field effect transistor 16, the drain of which is connected to the first 1 wire of the bus 4, the source is connected to the second 2 wire of the bus 4, and the gate is connected to the interface output of the microcontroller eleven.

The claimed dust sensor works as follows.

The interrogation and data collection of the dust sensor (multiple dust sensors) is carried out via the DALI interface from the higher controller (not shown). Recall that the DALI interface is a bidirectional two-wire digital interface, oriented for primary use in lighting technology. DALI wires (DALI+ and DALI-) are powered from outside by a special power supply 12 - 22 V with a current limiting function, normalized in value within the limits specified in the standard (0.25 A). The DALI wires 1 and 2 between the upstream controller and the microcontroller 11 of the dust sensor transmit data bit streams bidirectionally. At the command of the microcontroller 11, received from the higher-level controller via the DALI interface implemented in the bus 4, and transmitted (by means of a transistor switch 9 and an infrared emitter driver 8) to the infrared emitter 5, the latter emits pulsed light into the area of dust entry 12, and the photodetector 6 receives light reflected from dust. The photodetector 6 generates a current pulse proportional to the amount of light/dust detected and provides an analog voltage output signal to the analog-to-digital converter 10 of the microcontroller 11, synchronized with the pulse signal of the infrared emitter 5 after the signal amplifier from the photodetector 7 amplifies the signal. The value measured in this way is processed by the microcontroller 11 and transmitted digitally to the higher-level controller via the DALI interface implemented in the bus 4. The output switch 15 includes an n-type field effect transistor 16. When the gate of the transistor 16 of the output key 15 from the microcontroller 11 is high, the key 15 opens and closes the DALI+ wire to GND, forming a low level on the bus 4. Since the bus power supply 4, as mentioned above, has a normalized current limit, the current , flowing through the key 15, is also normalized in magnitude. When the key 15 arrives at the gate from the low level microcontroller 11, the key closes and opens the DALI + and GND wires, a high level is formed on bus 4. Accordingly, the sequence of high and low levels (bits) is perceived as a binary code. The bit stream itself is formed by the microcontroller 11.

The input switch 14 includes a bipolar n-p-n transistor 17. At a low level on the DALI+ wire, the voltage at the base of the transistor 17 of the key 14 is also low, the key 14 is also closed at the interface input of the microcontroller 11, which has a pull-up to a high level enabled (the built-in pull-up resistor PULL UP 13 is on). ), there is a high level. At a high level on the DALI+ wire, exceeding the sum of the stabilization voltage of the zener diode 20 and the voltage drop at the emitter junction of the key 14, the base current flows through the input circuit of the key 14, the key 14 is open, and a low level is formed at the interface input of the microcontroller 11. Processing of the received bit stream is also carried out by the microcontroller 11.

The conducted field experiments and the results of computer simulation showed that the bidirectional digital interface formed in the claimed manner in the dust sensor allows the sensor (many sensors) to be used in distributed digital monitoring systems based on road lighting objects using the DALI protocol profiled for them, providing the required quality of measurements.

The foregoing allows us to conclude that the identified problem has been solved, and the claimed technical result - enabling the use of a dust sensor in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them - has been achieved.

Claims (1)

A dust sensor containing an infrared emitter with a driver and a photodetector focused in the dust concentration measurement zone, connected respectively through a transistor switch and a signal amplifier to a microcontroller with a built-in analog-to-digital converter and interface input and output, and a microcontroller power supply, characterized in that it is equipped with an interface bus that includes a positive DALI+ wire and a negative DALI- wire connected to the circuit ground, and the microcontroller is equipped with input and output transistor switches, of which the input switch is made on a bipolar n-p-n transistor, the collector of which is connected to the interface input of the microcontroller with a built-in pull-up resistor, the emitter is connected to the DALI-interface bus wire, while the emitter junction of the transistor is shunted by a resistor connected between the emitter and the base, and the base is connected through a current-limiting resistor and a zener diode connected in series with the DALI+ wire interface bus, and the output switch is made on an n-type field effect transistor, the drain of which is connected to the DALI+ wire of the interface bus, the source is connected to the DALI-interface bus wire, and the gate is connected to the interface output of the microcontroller.

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