CN214843442U

CN214843442U - Wireless water meter circuit

Info

Publication number: CN214843442U
Application number: CN202120894376.7U
Authority: CN
Inventors: 梁友华; 张桂银
Original assignee: CROWN RICH ELECTRONIC (SHENZHEN) CO LTD
Current assignee: CROWN RICH ELECTRONIC (SHENZHEN) CO LTD
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2021-11-23
Anticipated expiration: 2031-04-27

Abstract

The utility model relates to a wireless water gauge circuit. The wireless water meter circuit comprises an MCU control circuit, an RF (radio frequency) transceiver circuit, a double reed pipe pulse detection circuit and a valve control circuit, wherein the MCU control module comprises a BC66F3652 control chip, and a full-duplex universal asynchronous transceiver and a Sub-1GHz FSK/GFSK transceiver are integrated in the BC66F3652 control chip; the RF transceiver circuit comprises an antenna J1, a PI type impedance matching circuit and an adjusting impedance matching circuit, and a Sub-1GHz FSK/GFSK transceiver in the BC66F3652 control chip is in wireless communication with the remote management center through the RF transceiver circuit; the double-reed-tube pulse detection circuit comprises a first reed tube, a second reed tube and a magnetic element. The wireless water meter circuit provided by the application adopts the BC66F3652 control chip, the BC66F3652 control chip not only has the SUB 1G wireless transceiving function, but also has the MCU with 8Kx16 program space, and the MCU does not need to be additionally added, so that the circuit structure is simple; compared with a Lora SX1278 chip adopted in the prior art, the chip is low in price and can effectively save cost.

Description

Wireless water meter circuit

Technical Field

The utility model relates to a wireless water gauge technical field especially relates to a wireless water gauge circuit.

Background

The intelligent water meter mainly comprises a wired water meter (RS485 BUS, M-BUS BUS) and a wireless water meter (GPRS/NB water meter, Zigbee and SUB 1G wireless). The wireless transmission mode has the advantages of low cost, convenient installation, distributed metering, data networking transmission, high speed and efficiency meter reading and the like.

Through development for many years, wireless water meter and meter reading technology are more and more mature, and become market mainstream at present. The Lora/SUB 1G wireless scheme is a design choice due to the advantages of long communication distance, strong anti-interference capability, free charge, low power consumption and the like, however, the Lora SX1278 chip has the problem of high price; although the prices of other SUB 1G chips such as Sheng Ke A7108 and SI4432 are not expensive, an MCU (such as STM8L052C6) needs to be added, so that the circuit structure is relatively complex.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a wireless water meter circuit of simple, with low costs of circuit structure.

For realizing the purpose of the utility model, the utility model adopts the following technical scheme:

a wireless water meter circuit comprises an MCU control circuit, an RF (radio frequency) transceiver circuit, a double reed pipe pulse detection circuit and a valve control circuit, wherein the MCU control module comprises a BC66F3652 control chip, a full-duplex universal asynchronous transceiver and a Sub-1GHz FSK/GFSK transceiver are integrated in the BC66F3652 control chip, and the BC66F3652 control chip is connected with external terminal equipment or tooling production test equipment through the full-duplex universal asynchronous transceiver;

the RF radio frequency transceiver circuit comprises an antenna J1, a PI type impedance matching circuit and an adjusting impedance matching circuit, the RF end of the BC66F3652 control chip is connected with the antenna J1 through the adjusting impedance matching circuit and the PI type impedance matching circuit in sequence, and the Sub-1GHz FSK/GFSK transceiver in the BC66F3652 control chip is in wireless communication with a remote management center through the RF radio frequency transceiver circuit;

the double-reed-tube pulse detection circuit comprises a first reed tube, a second reed tube and a magnetic element, wherein the magnetic element is arranged on a water meter counting disc, the first reed tube and the second reed tube are arranged above the water meter counting disc at intervals, and the external broken end of the BC66F3652 control chip is correspondingly connected with the first reed tube and the second reed tube; the valve control circuit comprises a motor valve, the control end of the motor valve is connected with the output end of the BC66F3652 control chip, and the detection end of the motor valve is connected with the first input end of the BC66F3652 control chip.

Compared with a traditional wireless water meter circuit, the wireless water meter circuit provided by the application adopts the BC66F3652 control chip, the BC66F3652 control chip not only has the SUB 1G wireless transceiving function, but also has the MCU with 8Kx16 program space, and the MCU does not need to be additionally added, so that the circuit structure is simple; compared with a Lora SX1278 chip adopted in the prior art, the chip is low in price and can effectively save cost.

In one embodiment, the adjusting impedance matching circuit comprises inductors L1-L2 and capacitors C1-C2, an RFIN terminal of the BC66F3652 control chip is connected to one end of the inductor L1 and one end of the capacitor C1, an RFOUT terminal of the BC66F3652 control chip is connected to one end of the inductor L2, the other end of the inductor L2 is connected to the other end of the inductor L1 and one end of the capacitor C2, and the other end of the capacitor C1 and the other end of the capacitor C2 are grounded; the PI type impedance matching circuit comprises inductors L3-L5 and capacitors C3-C5, one end of the inductor L3 is connected with the other end of the inductor L1, the other end of the inductor L3 is connected with one end of the inductor L4 and one end of the capacitor C3 respectively, the other end of the inductor L4 is connected with one end of the inductor L5 and one end of the capacitor C4 respectively, the other end of the inductor L5 is connected with one ends of the antenna J1 and the capacitor C5 respectively, and the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the capacitor C5 are all grounded.

In one embodiment, the RF transceiver circuit further includes a dc blocking circuit, an isolation circuit and a power filter circuit, wherein the dc blocking circuit includes capacitors C6-C7, the isolation circuit includes an inductor L6, the power filter circuit includes capacitors C8-C9 and a resistor R1, an RFIN terminal of the BC66F3652 control chip is respectively connected to one end of the inductor L1 and one end of the capacitor C1 through the capacitor C6, an RFOUT terminal of the BC66F3652 control chip is respectively connected to one end of the inductor L6 and one end of the capacitor C7, another terminal of the inductor L6 is respectively connected to one end of the resistor R1 and one end of the capacitor C8, another terminal of the resistor R1 is respectively connected to a power VCC terminal and one end of a capacitor C9, and another terminal of the capacitor C8 and another terminal of the capacitor C9 are grounded.

In one embodiment, the BC66F3652 wireless water meter circuit further comprises a power supply reverse connection prevention and filter circuit and a battery under-voltage detection circuit, wherein the power supply reverse connection prevention and filter circuit comprises a battery BT1, a diode D1 and capacitors C10-C12, the anode of the battery BT1 is connected with the anode of the diode, the cathode of the diode is respectively connected with one end of a capacitor C1O, one end of a capacitor C11, one end of a capacitor C12 and the power supply end of the BC66F3652 control chip, and the cathode of the battery BT1, the other end of the capacitor C10, the other end of the capacitor C11 and the other end of the capacitor C12 are all grounded; the battery under-voltage detection circuit comprises a resistor R2 and a resistor R3, one end of the resistor R2 is connected with the positive electrode of the battery BT1, the other end of the resistor R2 is respectively connected with one end of the resistor R3 and the second input end of the BC66F3652 control chip, and the other end of the resistor R3 is connected with the third input end of the BC66F3652 control chip.

Drawings

Fig. 1 is a schematic circuit diagram of a wireless water meter circuit according to an embodiment.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

Referring to fig. 1, the present embodiment provides a BC66F3652 wireless water meter circuit, which includes an MCU control circuit, an RF transceiver circuit, a double reed pipe pulse detection circuit, and a valve control circuit. The double reed switch pulse detection circuit is used for detecting the water consumption condition of a user; the MCU control circuit is in wireless communication with a remote management center through an RF (radio frequency) transceiver circuit and is used for upwards transmitting water consumption data detected by the double reed pipe pulse detection circuit to the remote management center in a wireless data communication mode, the remote management center is used for sending a water supply switch instruction to the MCU control circuit according to the current water consumption and the payment condition of a user, the MCU control circuit controls the start and stop of a water supply electric valve of the user through the valve control circuit according to the received water supply switch instruction, and the remote punitive water cut-off work of a malicious defaulting user is completed.

In this embodiment, the MCU control circuit includes a BC66F3652 control chip, the BC66F3652 is a taiwan shengguan semiconductor (also called tai), the autonomous 8-bit reduced RISC core MCU, the BC66F3652 control chip is internally integrated with a full-duplex universal asynchronous transceiver and a Sub-1GHz FSK/GFSK transceiver, and the BC66F3652 control chip is connected to an external terminal device or a tool production test device through the full-duplex universal asynchronous transceiver (i.e., a PD1 pin and a PD2 pin). Specifically, the external terminal device may be a mobile phone, a computer, or the like; PD1 and PD2 are serial communication receiving and sending ports respectively, and the communication interfaces are mainly used for writing and reading production test parameters of terminal equipment or tools.

The double-reed-tube pulse detection circuit comprises a first reed switch, a second reed switch and a magnetic element, wherein the magnetic element is arranged on a water meter counting disc, the first reed switch and the second reed switch are arranged nearby the upper part of the water meter counting disc at intervals, the external interrupt ends (PB1 pin and PB0 pin) of the BC66F3652 control chip are correspondingly connected with the first reed switch and the second reed switch, when a rotating disc rotates for one circle, a magnetic field generated by the magnetic element passes through the double-reed-tube once, and two metering pulses are generated at the external interrupt end of the BC66F3652 control chip. The working principle of pulse counting by adopting the double reed switches in the embodiment is as follows: when the two reed switches are sequentially closed, the water meter judges that sampling is effective once, and if only one reed is closed, the water meter does not measure; when the two reed pipes are closed simultaneously, the external strong magnetic interference is considered, and the MCU control circuit closes the valve through the valve control circuit. In fig. 1, PB2 is a common control terminal of 2 reed switches, and the low level is active; PB1 and PB0 are MCU control circuit's outside interrupt end, and the inside resistance that pulls up that takes can effectively detect tongue tube pulse signal.

The valve control circuit comprises a motor valve, wherein the control end (a forward rotation control end and a reverse rotation control end) of the motor valve is connected with the output end (a PC0 pin and a PC1 pin) of the BC66F3652 control chip, and the detection end of the motor valve is connected with the first input end (a PC2 pin and a PD0 pin) of the BC66F3652 control chip. When the residual water amount is-1 cubic meter, the BC66F3652 controls the chip to drive the motor valve to automatically close, cut off the water source and report to the remote management center; and only when the user purchases water again, the BC66F3652 control chip turns on the electric valve to supply water. The PC0 and the PC1 control the positive and negative rotation of the motor, and the PC2 and the PD0 are detection ends of the opening and closing states of the valve.

The RF radio frequency transceiver circuit comprises an antenna J1, a PI type impedance matching circuit and an adjusting impedance matching circuit, the RF end of a BC66F3652 control chip is connected with the antenna J1 sequentially through the adjusting impedance matching circuit and the PI type impedance matching circuit, a Sub-1GHz FSK/GFSK transceiver in the BC66F3652 control chip is in wireless communication with a remote management center through the RF radio frequency transceiver circuit, and the Sub-1GHz FSK/GFSK transceiver can be used for wireless communication application of frequency bands of 315MHz, 433MHz, 470MHz, 868MHz and 915 MHz.

Specifically, the adjusting impedance matching circuit comprises inductors L1-L2 and capacitors C1-C2, an RFIN end of a BC66F3652 control chip is respectively connected with one end of the inductor L1 and one end of the capacitor C1, an RFOUT end of the BC66F3652 control chip is connected with one end of the inductor L2, the other end of the inductor L2 is respectively connected with the other end of the inductor L1 and one end of the capacitor C2, and the other end of the capacitor C1 and the other end of the capacitor C2 are grounded; the PI type impedance matching circuit comprises inductors L3-L5 and capacitors C3-C5, one end of the inductor L3 is connected with the other end of the inductor L1, the other end of the inductor L3 is connected with one end of the inductor L4 and one end of the capacitor C3 respectively, the other end of the inductor L4 is connected with one end of the inductor L5 and one end of the capacitor C4 respectively, the other end of the inductor L5 is connected with one ends of an antenna J1 and a capacitor C5 respectively, and the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the capacitor C5 are all grounded.

Furthermore, the RF transceiver circuit may further include a dc blocking circuit, an isolation circuit and a power filter circuit, wherein the dc blocking circuit includes capacitors C6-C7, the isolation circuit includes an inductor L6, the power filter circuit includes capacitors C8-C9 and a resistor R1, an RFIN terminal of the BC66F3652 control chip is respectively connected to one end of the inductor L1 and one end of the capacitor C1 through a capacitor C6, an RFOUT terminal of the BC66F3652 control chip is respectively connected to one end of the inductor L6 and one end of the capacitor C7, another terminal of the inductor L6 is respectively connected to one end of the resistor R1 and one end of the capacitor C8, another terminal of the resistor R1 is respectively connected to the VCC terminal and one end of the capacitor C9, and another terminal of the capacitor C8 and another terminal of the capacitor C9 are grounded. Specifically, the inductor L6 is used to isolate the interference of the RF signal with VCC.

In the present embodiment, when the RF transceiver circuit receives a high frequency signal transmitted by a remote management center, in addition to the antenna J1, an impedance matching circuit is required to be added between the antenna J1 and the BC66F3652 control chip, as shown in fig. 1. Good impedance matching can reduce the amount of noise, thereby improving the receiving sensitivity. When the impedance matching is adjusted, a network analyzer is used for measurement in a matching mode, and the original elements for impedance matching are required to select a high-Q-value capacitor and an inductor, so that the receiving sensitivity can be effectively improved. Specifically, the suggested values of each frequency band of the PCB layout provided in this embodiment are as follows, and if the PCB layout mode is changed, the impedance matching circuit needs to be adjusted.

	315MHz	433MHz	470MHz	868MHz	Unit of
						C1	1.5	1	1	N.C	pF
C6	100	100	100	100	pF
						C7	100	68	68	68	pF
C5	12	10	8	N.C.	pF
						C4
	24	22	15	3.3	pF
						C3
	15	12	8	5.6	pF
						C2	N.C.	N.C.	N.C.	N.C.	-
L5	18	15	15	OR	nH
						L4	18	15	15	8.2	nH
L3	18	8.2	5.6	3.3	nH
						L1	82	68	47	18	nH
L6
		100	82	82	82	nH

The wireless water meter circuit provided by the embodiment adopts the BC66F3652 control chip, and the Sub-1GHz FSK/GFSK transceiver is integrated in the BC66F3652 control chip, so that the wireless water meter circuit can be applied to wireless communication in frequency bands of 315MHz, 433MHz, 470MHz, 868MHz and 915 MHz; two external interrupt pins shared with the I/O port are arranged, so that double reed switch pulse detection can be realized; meanwhile, the internal parts of all I/O ports can be configured with input weak pull-up, and external pull-up resistors can be omitted by detecting external keys or pulse input; the on-chip EEPROM data memory with 128 bytes can be used for storing parameters such as accumulated water consumption, water allowance and the like, and power-off data cannot be lost; meanwhile, a full-duplex universal asynchronous receiver/transmitter (UART) is provided, so that the writing and reading of production test parameters of terminal equipment or a tool can be easily connected; the programmable internal reference voltage 12-bit ADC is provided, so that the battery voltage can be accurately detected, and low voltage and timely valve closing protection can be realized; an 8Kx16 Flash program memory and a 512-byte RAM data memory are integrated on the chip, so that the software function of the low-power-consumption wireless intelligent water meter can be realized.

Compared with a traditional wireless water meter circuit, the wireless water meter circuit provided by the embodiment adopts the BC66F3652 control chip, the BC66F3652 control chip not only has the SUB 1G wireless transceiving function, but also has the MCU with 8Kx16 program space, and the MCU does not need to be additionally added, so that the circuit structure is simple; compared with a Lora SX1278 chip adopted in the prior art, the chip is low in price and can effectively save cost.

In one embodiment, referring to fig. 1, the BC66F3652 wireless water meter circuit further includes a power supply reverse connection prevention and filter circuit and a battery under-voltage detection circuit, wherein the power supply reverse connection prevention and filter circuit includes a battery BT1, a diode D1 and capacitors C10 to C12, an anode of the battery BT1 is connected to an anode of the diode, cathodes of the diodes are respectively connected to one end of a capacitor C1O, one end of a capacitor C11, one end of a capacitor C12 and a power supply end of a BC66F3652 control chip, and a cathode of the battery BT1, the other end of a capacitor C10, the other end of the capacitor C11 and the other end of the capacitor C12 are all grounded; the undervoltage detection circuit comprises a resistor R2 and a resistor R3, wherein one end of the resistor R2 is connected with the positive electrode of the battery BT1, the other end of the resistor R2 is respectively connected with one end of a resistor R3 and a second input end (PA4 pin) of the BC66F3652 control chip, and the other end of the resistor R3 is connected with a third input end (PD3 pin) of the BC66F3652 control chip.

In this embodiment, the battery BT1 may adopt a 3.6V disposable lithium battery, the motor valve is in an open state during normal operation, when the BC66F3652 control chip detects that the battery voltage is lower than 3V, the valve is automatically closed, corresponding data is stored, a water source is cut off, and the data is reported to the remote management center, and the valve is not opened until the BC66F3652 control chip changes the battery. The resistors R2 and R3 constitute a voltage divider circuit, PA4 is an AD detection port, and PD3 is a voltage detection control port. When the battery voltage needs to be detected, the PD3 outputs a low level, the PA4 is 1/2 of the battery voltage, and the voltage of the battery can be accurately detected through the internal 12-bit AD; when it is not necessary to detect the battery voltage, the PA4 and the PD3 are provided as common input ports, so that low power consumption can be achieved. The BC66F3652 controls the internal reference of the chip with 1.2V (+ -1%) and can be used as the reference voltage of ADC sampling.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A wireless water meter circuit is characterized by comprising an MCU control circuit, an RF (radio frequency) transceiver circuit, a double reed pipe pulse detection circuit and a valve control circuit, wherein the MCU control module comprises a BC66F3652 control chip, a full-duplex universal asynchronous transceiver and a Sub-1GHz FSK/GFSK transceiver are integrated in the BC66F3652 control chip, and the BC66F3652 control chip is connected with external terminal equipment or tooling production test equipment through the full-duplex universal asynchronous transceiver;

2. The wireless water meter circuit of claim 1, wherein the adjusting impedance matching circuit comprises inductors L1-L2 and capacitors C1-C2, wherein the RFIN terminal of the BC66F3652 control chip is connected to one terminal of the inductor L1 and one terminal of the capacitor C1, respectively, the RFOUT terminal of the BC66F3652 control chip is connected to one terminal of the inductor L2, the other terminal of the inductor L2 is connected to the other terminal of the inductor L1 and one terminal of the capacitor C2, and the other terminals of the capacitors C1 and C2 are grounded; the PI type impedance matching circuit comprises inductors L3-L5 and capacitors C3-C5, one end of the inductor L3 is connected with the other end of the inductor L1, the other end of the inductor L3 is connected with one end of the inductor L4 and one end of the capacitor C3 respectively, the other end of the inductor L4 is connected with one end of the inductor L5 and one end of the capacitor C4 respectively, the other end of the inductor L5 is connected with one ends of the antenna J1 and the capacitor C5 respectively, and the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the capacitor C5 are all grounded.

3. The wireless water meter circuit of claim 2, wherein the RF transceiver circuit further comprises a DC blocking circuit, an isolation circuit, and a power filter circuit, wherein the DC blocking circuit comprises capacitors C6-C7, the isolation circuit comprises an inductor L6, the power supply filter circuit comprises capacitors C8-C9 and a resistor R1, the RFIN end of the BC66F3652 control chip is respectively connected with one end of the inductor L1 and one end of the capacitor C1 through the capacitor C6, the RFOUT terminal of the BC66F3652 control chip is respectively connected with one terminal of the inductor L6 and one terminal of the capacitor C7, the other end of the inductor L6 is respectively connected with one end of the resistor R1 and one end of the capacitor C8, the other end of the resistor R1 is respectively connected with a power supply VCC end and one end of a capacitor C9, and the other end of the capacitor C8 and the other end of the capacitor C9 are grounded.

4. The wireless water meter circuit according to claim 1, wherein the BC66F3652 wireless water meter circuit further comprises a power supply reverse connection prevention and filter circuit and a battery under-voltage detection circuit, wherein the power supply reverse connection prevention and filter circuit comprises a battery BT1, a diode D1 and capacitors C10-C12, an anode of the battery BT1 is connected with an anode of the diode, cathodes of the diode are respectively connected with one end of a capacitor C1O, one end of a capacitor C11, one end of a capacitor C12 and a power supply end of the BC66F3652 control chip, and a cathode of the battery BT1, the other end of the capacitor C10, the other end of the capacitor C11 and the other end of the capacitor C12 are all grounded; the battery under-voltage detection circuit comprises a resistor R2 and a resistor R3, one end of the resistor R2 is connected with the positive electrode of the battery BT1, the other end of the resistor R2 is respectively connected with one end of the resistor R3 and the second input end of the BC66F3652 control chip, and the other end of the resistor R3 is connected with the third input end of the BC66F3652 control chip.