CN210089799U

CN210089799U - Water flow detection circuit based on single chip microcomputer AD detection

Info

Publication number: CN210089799U
Application number: CN201921041610.0U
Authority: CN
Inventors: 南燕; 葛沂杰; 袁学武; 孙贤义
Original assignee: Hefei Yingtang Electronics Co Ltd
Current assignee: Hefei Yingtang Electronics Co Ltd
Priority date: 2019-07-05
Filing date: 2019-07-05
Publication date: 2020-02-18
Anticipated expiration: 2029-07-05

Abstract

The utility model provides a rivers detection circuitry based on singlechip AD detects, through set up two probes in waiting to detect equipment, insert the singlechip after the partial pressure filtering, when rivers cross two metal probe, because the aquatic contains the reason of electrolyte, the resistance that becomes to have certain impedance between two metal probe, singlechip AD port gathers the voltage value that changes on the probe and judges whether lack of water, the detectable quality of water scope of this kind of detection mode is extensive, can detect the pure water that the TDS value is 4PPM even, be applicable to in some non-water storage formula drinking water system ice making equipment's the lack of water detection circuitry.

Description

Water flow detection circuit based on single chip microcomputer AD detection

Technical Field

The utility model relates to a rivers detection circuitry especially relates to a rivers detection circuitry based on singlechip AD detects.

Background

In industrial production and daily life and office, a plurality of drinking equipment need to use a device for detecting water level or water flow, such as a household water dispenser. The common water level or water flow detection device comprises a reed switch liquid level sensor and a flowmeter with a Hall sensor, the operating principle of the reed switch is only suitable for detecting standing liquid, flowing water flow cannot be detected, and the reed switch has strict requirements on the installation position when detecting the water level.

The Hall water flow sensor measures magnetic physical quantity by utilizing the Hall effect of a Hall element, a load resistor is connected in series with the positive pole of the Hall element, 5V detention voltage is connected, the direction of current is orthogonal to the direction of a magnetic field, when water pushes a magnetic rotor to rotate through a turbine switch shell, a rotating magnetic field with different magnetic poles is generated, magnetic induction lines are cut, and high and low pulse levels are generated. Because the output pulse signal frequency of the Hall element is in direct proportion to the rotating speed of the magnetic rotor, the rotating speed of the rotor is in direct proportion to the water flow, and then the water flow is judged according to the output pulse signal frequency. The flowmeter with the Hall sensor needs to connect a water pipe into the flowmeter, and water flows through the inside of the flowmeter to detect the flow, so that the flowmeter is complex to install, is not suitable for detecting the water level by using the Hall sensor when the whole structure is compact, and has higher cost.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the above problem, provide a rivers detection circuitry based on singlechip AD detects to a simple structure is provided, reasonable in design, and it is higher to detect the accuracy, the circuit structure of detectable rivers and water level.

The utility model discloses a following technical scheme realizes above-mentioned purpose:

the utility model provides a rivers detection circuitry based on singlechip AD detects, includes first probe, second probe and singlechip detection chip, be equipped with an equivalent resistance R0 between first probe and the second probe, still be equipped with a partial pressure filter circuit between first probe and the second probe, first probe passes through partial pressure circuit with the second probe and inserts singlechip detection chip, wherein:

the voltage division filter circuit comprises a voltage division resistor R1, a filter resistor R2 and a capacitor C1, one branch of the first probe is connected to an external direct current working voltage output end Vcc through the voltage division resistor R1, and the other branch of the first probe is connected to an AD port of the single chip microcomputer detection chip through the filter resistor R2; one branch of the second probe is directly connected to the analog GND port of the single chip microcomputer detection chip, and the other branch of the second probe is connected to the AD port of the single chip microcomputer detection chip through a capacitor C1.

Further preferably, the second probe is grounded through a capacitor Y2.

Further preferably, the resistance value of the divider resistor R1 is 510K Ω -1M Ω, which can improve the measurement accuracy, so that the circuit of the present application can detect pure water with very low electrolyte content.

Further preferably, the filter resistor R2 is a carbon film resistor of 2K Ω, and the capacitor C1 is a ceramic chip capacitor of 0.1 uF.

Further preferably, the model of the single chip microcomputer detection chip is HR7P 169B.

The beneficial effects of the utility model reside in that:

1) the utility model can be applied to the equipment which can not use the Hall sensor or the reed pipe to detect the water level because of the structural design limitation of the product, and can detect the water flow speed and the state of water shortage or not;

2) the detectable water quality range of the utility model is wide, even pure water with TDS value of 4PPM can be detected, and the utility model is suitable for water shortage detection circuits of some non-water storage type drinking water making and ice making equipment;

3) the utility model discloses circuit structure is simple, and required components and parts are few, and the erroneous judgement rate is low.

Drawings

Fig. 1 is a schematic view of the overall structure of the water flow detection circuit based on the single chip microcomputer AD detection of the present invention;

FIG. 2 is a schematic diagram of the overall circuit structure of the water flow detection circuit based on the single chip AD detection of the present invention;

fig. 3 is the utility model discloses a rivers detection circuitry's interface connection schematic diagram based on singlechip AD detects.

Detailed Description

The present application will now be described in further detail with reference to the drawings, it should be noted that the following detailed description is given for illustrative purposes only and is not to be construed as limiting the scope of the present application, as those skilled in the art will be able to make numerous insubstantial modifications and adaptations to the present application based on the above disclosure.

Example 1

This embodiment provides a rivers detection circuitry based on singlechip AD detects, as shown in fig. 1, 2, 3, for 8 serial 20PIN foot singlechips HR7P169B that use the dongfu soft carrier wave carry out water level AD to detect for the singlechip detects the chip and carry out the structure chart and the circuit schematic diagram that water level AD detected on ice maker product, including first probe, second probe and HR7P169B singlechip chip, it is right below to combine the figure the utility model discloses a circuit structure explains in detail.

As shown in fig. 1, the first probe and the second probe are both metal conductors and are independently installed on an ice making box of an ice making machine, the two probes are not in contact with each other, and water flow to be detected can simultaneously flow through the two probes. An equivalent resistor R0 is arranged between the two probes, when no water flows through the two probes, an open circuit is formed between the two probes, the resistance value of the equivalent resistor R0 is infinite, when water flows through the two probes, due to the existence of electrolyte in water, the resistance value of the equivalent resistor R0 between the first probe and the second probe is in a detectable range, and the resistance value of the equivalent resistor R0 is different according to different electrolytes in water. When the content of impurities such as electrolyte is high, the smaller the resistance of the equivalent resistance R0 is, and the lower the electrolyte content is, the larger the equivalent resistance is.

As shown in fig. 2, the HR7P169B single chip has a 16KByte FLASH program storage space, a 1KByte SRAM data storage, and an ADC having a 12-bit AD conversion result up to 15 channels, the AD ports are rich in favor of the layout of the PCB board, the MCU ports in fig. 2 are labeled with AIN and can be used as AD acquisition ports, the AD sampling precision of 12 bits improves the accuracy of the water level detection result, and the large capacity FLASH and SRAM space meets the processing of AD sampling data.

As shown in fig. 2 and 3, two probes are connected to an electric control board through lead wires, and are connected to an HR7P169B single chip after voltage division and filtering of a circuit on the electric control board.

The voltage division filter circuit comprises a voltage division resistor R1, a filter resistor R2 and a capacitor C1, wherein:

one branch of the first probe is connected to an external direct-current working voltage output terminal Vcc through a voltage dividing resistor R1, wherein the Vcc is determined according to the working voltage of a single chip microcomputer detection chip, for example, 3.3V or 5V, and the HR7P169B single chip microcomputer chip of the embodiment is 5V; the equivalent resistor R0 and the divider resistor R1 form a voltage dividing circuit, the divided voltage Uad0 is Vcc R0/(R0+ R1), the resistance value of the divider resistor R1 is preferably 510K omega-1M omega, and pure water with very low electrolyte content can be detected under the resistance value;

one branch of the second probe is directly connected to an analog GND port of an HR7P169B single-chip;

due to water flow fluctuation and noise interference on Vcc and GND lines, the equivalent resistor R0 after voltage division cannot be directly connected to the AD port of the single chip microcomputer detection chip, and therefore, the equivalent resistor R2 and the capacitor C1 need to be connected to the AD port of the single chip microcomputer detection chip. In this embodiment, the other branch of the first probe is connected to an AD port of the HR7P169B monolithic chip through a filter resistor R2 and the other branch of the second probe is connected to an AD port of the HR7P169B monolithic chip through a capacitor C1, where the filter resistor R2 is a carbon film resistor of about 2K Ω, and the capacitor C1 is a ceramic chip capacitor of 0.1 uF. R2 and C1 main effect are the interference noise on the filtering sampling signal, and the influence to gathering voltage is very little, can neglect, so finally insert AD mouth up-sampling signal voltage Uad of singlechip detection chip and be approximately equal to Uad0, and singlechip detection chip judges water flow rate and whether lack of water according to the voltage value of sampling Uad: when Uad is always in the fluctuation state, it indicates that the device is in the water adding state, and the water flow rate is larger, the Uad value is smaller, when Uad is stabilized at a fixed value, it indicates that the water quantity has flooded two probes, and it is in the full water state.

Further, since the second probe is directly connected to the analog GND port of the HR7P169B monolithic chip, Vcc and GND must be isolated from the incoming mains in view of electrical safety. Therefore, if there is a ground line on the casing of the device body to be tested, it is necessary to short-circuit the probe (second probe) connected to GND with the ground line connected to the casing of the device body to be tested through a capacitor Y2 according to the safety requirements.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. The utility model provides a rivers detection circuitry based on singlechip AD detects, includes first probe, second probe and singlechip detection chip, its characterized in that, be equipped with an equivalent resistance R0 between first probe and the second probe, still be equipped with a partial pressure filter circuit between first probe and the second probe, first probe passes through partial pressure circuit with the second probe and inserts singlechip detection chip, wherein:

2. The water flow detection circuit based on the AD detection of the single chip microcomputer as claimed in claim 1, wherein the second probe is grounded through a capacitor Y2.

3. The water flow detection circuit based on the AD detection of the single chip microcomputer as claimed in claim 1, wherein the resistance value of the voltage dividing resistor R1 is 510K Ω -1M Ω.

4. The water flow detection circuit based on the AD detection of the single chip microcomputer as claimed in claim 1, wherein the filter resistor R2 is a carbon film resistor of 2K Ω, and the capacitor C1 is a ceramic chip capacitor of 0.1 uF.

5. The water flow detection circuit based on the AD detection of the single chip microcomputer according to the claim 1, wherein the type of the single chip microcomputer detection chip is HR7P 169B.