CN109638942B - Passive wireless hydrogen sensing label and system - Google Patents
Passive wireless hydrogen sensing label and system Download PDFInfo
- Publication number
- CN109638942B CN109638942B CN201811607863.XA CN201811607863A CN109638942B CN 109638942 B CN109638942 B CN 109638942B CN 201811607863 A CN201811607863 A CN 201811607863A CN 109638942 B CN109638942 B CN 109638942B
- Authority
- CN
- China
- Prior art keywords
- resistor
- output
- voltage
- mcu
- passive wireless
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/20—Circuit arrangements or systems for wireless supply or distribution of electric power using microwaves or radio frequency waves
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/30—Services specially adapted for particular environments, situations or purposes
- H04W4/38—Services specially adapted for particular environments, situations or purposes for collecting sensor information
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
The invention discloses a passive wireless hydrogen sensing tag and a system, aiming at the problems of incapability of continuous collection, large volume, high cost, inconvenience in maintenance and the like of the existing wireless sensing network, the passive wireless hydrogen sensing tag is adopted to collect the ambient hydrogen concentration, a charging and discharging management circuit which saves more power consumption is designed for the passive wireless hydrogen sensing tag, the tag power consumption is reduced, two modes of bridge balance adjustment are provided for a hydrogen sensor realized by adopting a Wheatstone bridge, the reliability of ambient hydrogen concentration data collection is ensured, the cost is reduced, and meanwhile, the safety of dangerous gas concentration measurement work is ensured by adopting the passive wireless collection mode.
Description
Technical Field
The invention belongs to the field of Internet of things and communication, and particularly relates to a radio frequency identification and wireless sensor network technology.
Background
In recent years, with the rise of Internet of things (IoT), Wireless Sensor Networks (WSNs) have attracted much attention, and Radio Frequency Identification (RFID) is rapidly becoming one of the core technologies of Wireless Sensor Networks under its mature technical conditions.
The wireless sensor network is a distributed sensing network, and nodes of the wireless sensor network can detect specific information in the surrounding environment, such as earthquake, electromagnetism, temperature, humidity, pressure, object size, moving direction and speed, gas concentration information and the like. The traditional sensing network is powered by a battery, and the battery needs to be frequently replaced and the wireless sensing network needs to be manually maintained and the like, and the wireless sensing network cannot continuously work when the wireless sensing network normally works (control equipment reads sensing node information when the sensing network is needed and is in a dormant or power-off state at other time), so that the wireless sensing network node is the best solution by adopting a passive wireless working mode.
At present, sensors for testing information such as temperature, humidity and pressure in a passive and wireless mode are common, however, no solution for testing gas concentration in a passive and wireless mode exists, devices on the market are handheld, the cost is high, and due to the fact that many gases in the air are harmful to human bodies, such as carbon monoxide and methane, and are flammable and explosive gases, such as hydrogen and the like, although harmless to the human bodies, the passive wireless non-line-of-sight testing scheme is the optimal solution for gas detection.
Combining the above analysis, the main problems faced by the wireless sensor network are as follows: 1) the network node is powered by a battery and cannot meet the requirement of wireless energy collection and sustainable work; 2) the existing gas testing instrument is large in size, heavy, high in cost, inconvenient to maintain and high in safety performance due to an active working mode.
Disclosure of Invention
In order to solve the technical problems, the invention provides a passive wireless hydrogen sensing tag and a system, which are used for realizing wireless non-line-of-sight testing of gas concentration in the environment.
The invention adopts the scheme that: a passive wireless hydrogen sensing tag comprising: the system comprises a hydrogen sensor, a charge and discharge management circuit, an antenna, a matching network, a rectifying circuit, a radio frequency front end, an MCU (microprogrammed control unit), a sensor conditioning circuit and a modulation circuit;
the hydrogen sensor is realized by adopting a Wheatstone bridge type and consists of four hydrogen-sensitive variable resistance units, wherein two hydrogen-sensitive variable resistance units are working units, and the other two hydrogen-sensitive variable resistance units are reference units; the bottom layer of the working unit is an insulating layer, and the sensitive film layer is a palladium electrode; the hydrogen can cause the resistivity of the palladium to change, the resistance value of the bridge arm is increased along with the increase of the hydrogen concentration, but the reference unit adopts the silicon nitride to seal the sensitive layer, only responds to the temperature and is used for eliminating the temperature drift.
The antenna receives electromagnetic wave signals and converts the electromagnetic wave signals into alternating current signals, the alternating current signals are converted into direct current signals through a rectifying circuit after passing through a matching network, and the direct current signals are input to the input end of the charging and discharging management circuit; a stable voltage source output by the charging and discharging management circuit provides voltage for the radio frequency front end, the MCU, the sensor and the sensor conditioning circuit;
the radio frequency front end demodulates a command received by the antenna and sends the demodulated data to the MCU, the sensor carries out gas data acquisition according to a control signal sent by the MCU and sends the acquired gas data to the MCU, the MCU sends the gas data to the modulation circuit, and the modulated signal is sent out through the antenna.
The invention provides a technical scheme of a more energy-saving charge and discharge management circuit, which comprises the following steps: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a first diode, a second diode, a first PMOS (P-channel metal oxide semiconductor) tube, a second PMOS tube, a first NMOS (N-channel metal oxide semiconductor) tube and a second NMOS tube; the LDO is also included;
the first end of the first resistor is connected with the first end of the second resistor, the first end of the first resistor, which is used as the first end of the charge-discharge management circuit, is connected with input voltage, the second end of the first resistor is connected with the anode of a first diode, the cathode of the first diode is connected with the first end of a first capacitor, and the second end of the first capacitor is grounded; the second end of the second resistor is connected with the anode of a second diode, the cathode of the second diode is connected with the first end of a second capacitor, and the second end of the second capacitor is grounded;
the negative electrode of the first diode is connected with the source electrode of the first PMOS tube, the negative electrode of the first diode is also connected with the source electrode of the second PMOS tube, and the drain electrode of the second PMOS tube is used as the output end of the charge-discharge management circuit; the input end of the LDO is connected with the output end of the charge-discharge management circuit, and the output end of the LDO is used for outputting a stable voltage source;
the cathode of the second diode is connected with the grid electrode of the first PMOS tube, the grid electrode of the first PMOS tube is also connected with the grid electrode of the first NMOS tube, the drain electrode of the first PMOS tube is connected with the drain electrode of the first NMOS tube, the drain electrode of the first PMOS tube is also connected with the grid electrode of the second PMOS tube, the source electrode of the first NMOS tube is connected with the first end of the fourth resistor, and the second end of the fourth resistor is grounded;
the cathode of the second diode is also connected with the drain of a second NMOS transistor, the source of a second NMOS switch is connected with the first end of a third resistor, the second end of the third resistor is grounded, and the grid of the second NMOS transistor is used as the second input end of the charge-discharge management circuit and is connected with an external control signal; and an external control signal is input from the second input end of the charge and discharge management circuit to control the second NMOS tube to be opened so as to discharge the second capacitor.
In order to solve the problem of unbalanced sensor output, the invention also provides a technical scheme for balance adjustment of the sensor bridge, which comprises two modes, namely adjustment by adopting a parallel sliding resistor and automatic adjustment; the sensor conditioning circuit at least comprises an amplifier, wherein the Wheatstone bridge comprises two output voltages, one of the output voltages is connected with the non-inverting input end of the amplifier, and the other output voltage is connected with the inverting input end of the amplifier.
The adjustment of the sliding resistance in parallel is adopted, and the method specifically comprises the following steps: when the voltage of the non-inverting input end of the amplifier is far larger than that of the inverting input end, the voltage of the non-inverting input end is reduced by connecting a sliding resistor in parallel; when the voltage of the non-inverting input end of the amplifier is far smaller than that of the inverting input end, the voltage of the non-inverting input end is increased through the parallel sliding resistor.
The method for automatically adjusting the bridge balance specifically comprises the following steps: the sensor conditioning circuit also comprises a fifth resistor, a sixth resistor and a DAC (digital-to-analog converter) carried by the MCU; the output end of the DAC is connected with the REF of the instrument amplifier, the first end of the fifth resistor is connected with the output end of the instrument amplifier, the second end of the fifth resistor is connected with the first end of the sixth resistor, the second end of the sixth resistor is grounded, and the second end of the fifth resistor is also connected with the FB of the instrument amplifier.
The process of automatically adjusting the bridge balance is as follows:
s1, firstly testing a Wheatstone bridge type, wherein the type comprises the following steps: the first output voltage is far greater than the second output voltage, and the first output voltage is far less than the second output voltage;
s2, inputting the larger one of the first output voltage and the second output voltage into the non-inverting input end of the instrumentation amplifier, and inputting the smaller one into the output end of the instrumentation amplifier;
s3, continuously collecting the output signal of the instrumentation amplifier after the MCU receives the leveling bridge command;
s4, if the output signal of the instrumentation amplifier is larger than the set bridge output minimum value, executing a step S5; if the output signal of the instrumentation amplifier is smaller than the set bridge output minimum value, executing step S6; otherwise, the Wheatstone bridge is considered to be balanced;
s5, the MCU outputs a larger digital signal to control the DAC to output a larger voltage; then returning to the step S3 to continue to collect the output signal of the instrumentation amplifier;
s6, the MCU outputs a small digital signal to control the DAC to output a small voltage; and then returns to step S3 to continue to collect the output signal of the instrumentation amplifier.
The invention also provides a passive wireless hydrogen sensing system adopting the passive wireless hydrogen sensing tag, and further comprises a reader-writer and an upper computer, wherein the communication protocol between the reader-writer and the tag is ISO/IEC 18000.
The passive wireless hydrogen sensing tag is produced by adopting a flexible circuit board manufacturing process so as to meet the attaching requirements of various surfaces which can be bent.
The invention has the beneficial effects that: the invention provides a passive wireless hydrogen sensing label and a system, which adopt a passive wireless mode to collect energy, supply power to a label system to test the hydrogen concentration in the surrounding environment and adopt a wireless mode to transmit sensor data, wherein the label is produced by adopting a flexible circuit board manufacturing process and can meet various attaching requirements of bendable surfaces; the system can realize the communication function of long-distance passive wireless and non-line-of-sight, overcomes the defects that the system can only pass through a manual test in a short distance, especially brings safety guarantee for testing dangerous goods, and also overcomes the defects that an active tag has short service life and needs frequent battery replacement, and can meet the requirements of wireless sensing network nodes on low cost, high safety, low power consumption and continuous work in the Internet of things; the invention has the following advantages:
1. the charge and discharge management circuit has the effect of saving energy, is suitable for charge and discharge management of the wireless sensor network node, and provides reference for other low-power-consumption circuits and system designs;
2. the scheme of manually adjusting the output balance of the hydrogen sensor bridge and automatically adjusting the bridge balance solves the problem of unbalanced sensor output, so that data acquisition is more reliable, and the method is suitable for all circuits realized in a bridge mode;
3. the invention provides a user-defined command for communication between an upper computer and a gas sensor tag, the user-defined command is compatible with a traditional reader-writer supporting ISO/IEC18000 standards, the reader-writer does not need to be modified, and the data acquisition function of a hydrogen sensor is realized on the basis;
4. the invention provides a passive wireless hydrogen sensing tag by using a microcontroller, which improves the service life of the tag, and also provides a method for acquiring hydrogen concentration information and a whole set of feasible communication technical scheme based on the tag, so that the gas concentration is more convenient to measure, the safety of dangerous gas concentration measurement is improved, and the cost is reduced.
Drawings
Fig. 1 is a diagram of a passive wireless hydrogen sensing tag and system architecture according to an embodiment of the present invention;
fig. 2 is a charging and discharging management circuit according to an embodiment of the present invention;
FIG. 3 illustrates an RFID protocol implementation and gas data collection process provided by an embodiment of the present invention;
FIG. 4 is a schematic diagram of a method for manually adjusting the balance of a class a bridge according to an embodiment of the present invention;
FIG. 5 illustrates a method for manually adjusting the balance of a class b bridge according to an embodiment of the present invention;
fig. 6 is a diagram illustrating an embodiment of the present invention for automatically adjusting bridge balance.
Detailed Description
In order to facilitate the understanding of the technical contents of the present invention by those skilled in the art, the present invention will be further explained with reference to the accompanying drawings.
In order to solve the problems of low safety and high cost in gas detection, the invention provides a passive wireless hydrogen sensing tag system, as shown in fig. 1, comprising: host computer, read write line, passive wireless hydrogen sensing label.
The hydrogen sensor is realized by adopting a Wheatstone bridge type and consists of four hydrogen-sensitive variable resistance units, wherein two hydrogen-sensitive variable resistance units are working units (such as Rx1 and Rx2 in the graph of 4/5), and the other two hydrogen-sensitive variable resistance units are reference units (such as R1 and R2 in the graph of 4/5); the bottom layer of the working unit is an insulating layer, and the sensitive film layer is a palladium electrode; the hydrogen can cause the resistivity of the palladium to change, the resistance value of the bridge arm is increased along with the increase of the hydrogen concentration, but the reference unit adopts the silicon nitride to seal the sensitive layer, only responds to the temperature and is used for eliminating the temperature drift.
The passive wireless hydrogen sensing tag adopts a flexible plate manufacturing process and is an ISO/IEC18000 ultrahigh frequency RFID passive wireless hydrogen sensing tag based on an MCU. Because of the discrete type of the sensor, a comparison table needs to be established for the acquired sensor data and the hydrogen concentration, calibration is needed to improve the acquisition precision of the sensor before the label is used, the acquired sensor data is tested in different hydrogen concentration environments, and a reference comparison table is established according to the acquired data and the hydrogen concentration. When the label is normally used, the working state of the reader-writer is controlled through the software of the upper computer, the software of the upper computer controls the reader-writer to send a sensor data acquisition command, the reader-writer feeds back the received sensor data returned by the label to the upper computer, the upper computer analyzes the received sensor data, the data is used for looking up a table in a comparison table of hydrogen concentration and acquisition data, and the hydrogen concentration in the environment where the label is located during the detection can be inquired.
When the system works normally, the upper computer firstly initializes the working mode of the reader-writer, after the reader-writer receives an inventory command sent by the upper computer, the reader-writer firstly sends continuous carrier waves to charge surrounding tags, then sends the tags existing around the inventory command, after the tags around the inventory of the reader-writer are finished, the upper computer selects a certain tag to access by configuring the reader-writer to send a selection command with a specific tag ID, and then the upper computer configures the reader-writer to send a reading command, in order to be completely compatible with an ISO/IEC18000 protocol, the system provides that a user storage area address 0x10 represents the collection of single sensor data, and stores the data in a user area address 0x11 so as to be directly read next time; reading user zone 0x12 indicates that sensor data is collected multiple times and stored in the user zone starting at address 0x13 so that it can be read directly the next time; reading other addresses or other commands indicates implementing the function of the generic RFID tag. After receiving a data acquisition command sent by the reader-writer, the tag sends acquired sensor data to the reader-writer, the reader-writer then feeds back the acquired sensor data to the upper computer, and the upper computer obtains the hydrogen concentration of the environment where the tag is located through the sensor acquisition data generated during calibration and a hydrogen concentration comparison table and displays the hydrogen concentration.
The embodiment of the present invention provides a specific implementation manner of a charge and discharge management circuit, as shown in fig. 2, Vrec is an output voltage of a rectifier circuit, R0, R1, R2, and R3 are resistors, D0 and D1 are diodes, which are used to implement a unidirectional conduction function, P0, P1, N0, and N1 are MOS (Metal Oxide Semiconductor) transistors, which are used as switching tubes; an LDO (Low dropout regulator) is used to output a stable voltage source; the Load is a Load circuit, and comprises an MCU (microprogrammed control unit) of the sensor tag, a radio frequency front end, a modulation circuit and a sensor conditioning circuit. The charging and discharging management circuit controls the charging time of C0 and C1 by adjusting the sizes of R0 and R1, C0 is used as a main power supply, C1 is used as a control enabling signal, when the output of C1 through an inverter (the inverter is a device with high-level input and low-level output or low-level input and high-level output, namely the inverter consisting of P0 and N0) is low, P1 is conducted, and C0 provides a stable voltage source for the MCU, the radio frequency front end, the modulation circuit and the sensor conditioning circuit through the LDO; the MCU realizes RFID protocol and sensor data acquisition, and the MCU can discharge to the C1 by opening the switch tube N1 so as to save energy in the C0 and save energy.
In the flow of implementing the RFID protocol and acquiring the gas data, as shown in fig. 3, the MCU implements the flow of implementing the RFID protocol and the sensor data acquisition function based on the ISO/IEC18000 standard, and is used for implementing the RFID protocol and the hydrogen data acquisition meeting the ISO/IEC18000, energy-saving control and the like. The embodiment adopts the MSP430 series single-chip microcomputer, has low power consumption, has functions of ADC (analog-to-digital conversion), DAC (digital-to-analog conversion) and the like, and is very suitable for sensor data acquisition.
The specific process is as follows:
when the tag receives continuous carriers sent by a reader-writer, firstly, a radio frequency signal is converted into an alternating current signal by the tag antenna, then the alternating current signal is converted into a direct current voltage signal by the rectifying circuit, the direct current voltage charges the energy storage capacitor through the charging and discharging management circuit, and when the voltage C1 of the enabling signal reaches a set starting voltage, the charging and discharging management circuit supplies power to the active element.
After the MCU is electrified, the working state of the pin of the MCU is initialized, the interrupt enabling function of the pin for receiving the command is started, and then the front end of the radio frequency receiving terminal is waited to receive the command sent by the reader-writer.
If the label receives a general RFID command, the label executes the command as a common label meeting an RFID protocol, confirms whether a signal is returned or not, then sends an energy-saving control signal to close a power supply switch, and after the power supply switch is closed, the MCU enters a power-down state to wait for the next time when the upper computer sends a continuous carrier wave and a command;
if the label receives a sensor bridge leveling command, the MCU executes the function of automatically adjusting the bridge balance, and stores the current DAC input digital data after the bridge is balanced, so that the current DAC input digital data can be conveniently used when the bridge is electrified next time;
if the label receives a sensor data acquisition command, the MCU firstly enables the sensor circuit, then configures the working mode of the ADC and waits for the sensor circuit to work stably, then the MCU judges whether the acquisition is single acquisition or repeated acquisition according to the received command and starts to acquire data, the data is returned to the reader-writer after the data is acquired, the reader-writer transmits the data to an upper computer, finally a power supply switch is closed through an energy-saving control signal, the MCU enters a power-off state and waits for the next time for the reader-writer to send continuous carriers and commands.
The embodiment provides a specific implementation manner for manually adjusting the output balance of the hydrogen sensor bridge, as shown in fig. 4 and 5; the dashed boxes indicate the need to determine whether a sliding rheostat needs to be added based on the particular sensor. R1 and R2 in fig. 4 and 5 are fixed resistances, and a sliding varistor Rv1 and Rv2 is connected in parallel to two ends of one of the resistors R1 and R2 to adjust the bridge balance. A1 denotes an amplifier, preferably an instrumentation amplifier, the non-inverting input end of which is fed by a high voltage of two output voltages of a bridge; for convenience of description, the output point of the bridge connected to the non-inverting input terminal of the instrumentation amplifier is denoted as point a, and the output point of the bridge connected to the inverting input terminal of the instrumentation amplifier is denoted as point B.
Before determining which resistance to solder a sliding rheostat across, testing whether the sensor output is balanced (testing in an environment with a gas concentration of 0), if the bridge is substantially balanced and the potential at point a is slightly higher than the potential at point B and does not cause the amplifier output to saturate, then the gas sensor does not add a sliding rheostat; if the bridge is unbalanced and the potential of the point A is higher than that of the point B by more than 1mV (called a type a bridge), as shown in FIG. 4, sliding varistors are connected in parallel at two ends of R2, the sliding varistors are not connected in parallel at two ends of R1, the effective resistance value of R2 on the bridge is reduced by sliding the sliding varistors Rv2 at two ends of R2, and the potential of the point A is reduced, so that the bridge can be controlled to be in a basic balance state; if the bridge is unbalanced and the potential of the point A is lower than the potential of the point B by more than 1mV (called a class B bridge), the bridge is rotated by 90 degrees, and as shown in FIG. 5, the potential of the point A is still lower than the potential of the point B, sliding varistors are connected in parallel at two ends of R1, and the sliding varistors are not connected in parallel at two ends of R2, so that the effective resistance value of R1 on the bridge can be reduced by sliding the sliding varistors Rv1 at two ends of R1, the potential of the point A is increased, and the bridge can be controlled to. The rheostat is added on the fixed arms of the class a bridge and the class B bridge in a sliding mode, the bridge is adjusted to be in a state close to balance (the potential of the point A is within 1mV of the potential of the point B), so that the input of the amplifier has a slight offset, the offset is determined by the sensitivity of the gas sensitive element to the gas concentration change, and the requirement that the acquisition precision of sensor data is met and the amplifier is not saturated is met. The output has a small bias, which can solve the problem that the ADC acquisition is unreliable because the output of the amplifier is near zero.
The embodiment provides a specific implementation mode for automatically adjusting the balance of the bridge; as shown in fig. 6, an instrumentation amplifier supporting an indirect current feedback architecture can achieve this function by adjusting the size of REF to balance the bridge. The bridge of fig. 6 first needs to test by hand whether the sensor is a class a or b bridge and connect the large output end of the bridge to the non-inverting input of the amplifier, where R3 and R4 determine the amplification of amplifier a 1. After the tag receives a leveling bridge command, the MCU continuously collects the output signals of the amplifier and compares the output signals with the level of the amplifier, if the collected data is too large, the MCU outputs a larger digital signal (ctrl _ data) to control the DAC to output a larger voltage, and the output signals of the amplifier are continuously collected; if the collected data is too small, outputting a smaller digital signal (ctrl _ data) through the MCU to control the DAC to output a smaller voltage, and continuously collecting the output signal of the amplifier; until the amplifier output signal is equal to or just less than the bridge output minimum value set by the MCU (i.e., the set bridge output balance value), the MCU assumes that the bridge is balanced. The intermediate current feedback instrumentation amplifier of the present embodiment may employ an AD8237 device.
It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A charge and discharge management circuit, comprising: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a first diode, a second diode, a first PMOS (P-channel metal oxide semiconductor) tube, a second PMOS tube, a first NMOS (N-channel metal oxide semiconductor) tube and a second NMOS tube;
the first end of the first resistor is connected with the first end of the second resistor, the first end of the first resistor, which is used as the first end of the charge-discharge management circuit, is connected with input voltage, the second end of the first resistor is connected with the anode of a first diode, the cathode of the first diode is connected with the first end of a first capacitor, and the second end of the first capacitor is grounded; the second end of the second resistor is connected with the anode of a second diode, the cathode of the second diode is connected with the first end of a second capacitor, and the second end of the second capacitor is grounded;
the negative electrode of the first diode is connected with the source electrode of the first PMOS tube, the negative electrode of the first diode is also connected with the source electrode of the second PMOS tube, and the drain electrode of the second PMOS tube is used as the output end of the charge-discharge management circuit;
the cathode of the second diode is connected with the grid electrode of the first PMOS tube, the grid electrode of the first PMOS tube is also connected with the grid electrode of the first NMOS tube, the drain electrode of the first PMOS tube is connected with the drain electrode of the first NMOS tube, the drain electrode of the first PMOS tube is also connected with the grid electrode of the second PMOS tube, the source electrode of the first NMOS tube is connected with the first end of the fourth resistor, and the second end of the fourth resistor is grounded;
the cathode of the second diode is also connected with the drain of a second NMOS tube, the source of the second NMOS tube is connected with the first end of a third resistor, the second end of the third resistor is grounded, and the grid of the second NMOS tube is used as the second input end of the charge-discharge management circuit and is connected with an external control signal.
2. The charge and discharge management circuit according to claim 1, wherein an external control signal is inputted from the second input terminal of the charge and discharge management circuit to control the second NMOS transistor to be turned on to discharge the second capacitor.
3. The charge and discharge management circuit according to claim 1, further comprising an LDO, wherein an input terminal of the LDO is connected to an output terminal of the charge and discharge management circuit, and an output terminal of the LDO is configured to output a stable voltage source.
4. A passive wireless hydrogen sensing tag, characterized by comprising at least the charge and discharge management circuit of claim 3 and a hydrogen sensor implemented with wheatstone bridge;
further comprising: the system comprises an antenna, a matching network, a rectifying circuit, a radio frequency front end, an MCU, a sensor conditioning circuit and a modulation circuit;
the antenna receives electromagnetic wave signals and converts the electromagnetic wave signals into alternating current signals, the alternating current signals are converted into direct current signals through a rectifying circuit after passing through a matching network, and the direct current signals are input to the input end of the charging and discharging management circuit; a stable voltage source output by the charging and discharging management circuit provides voltage for the radio frequency front end, the MCU, the hydrogen sensor and the sensor conditioning circuit;
the radio frequency front end demodulates a command received by the antenna and sends the demodulated data to the MCU, the hydrogen sensor carries out gas data acquisition according to a control signal sent by the MCU and sends the acquired gas data to the MCU, the MCU sends the gas data to the modulation circuit, and the modulated signal is sent out through the antenna.
5. A passive wireless hydrogen sensing tag according to claim 4, wherein the sensor conditioning circuit comprises at least an amplifier, and the Wheatstone bridge comprises two output voltages, one of which is connected to the non-inverting input of the amplifier and the other of which is connected to the inverting input of the amplifier.
6. A passive wireless hydrogen sensing tag according to claim 5, wherein the amplifier is an instrumentation amplifier.
7. The passive wireless hydrogen sensing tag of claim 5 or 6, wherein when the difference between the voltage at the in-phase input and the voltage at the reverse phase input is greater than 0.1mV, the voltage at the in-phase input is reduced by connecting a sliding resistor in parallel;
when the difference value of the voltage of the inverting input end minus the voltage of the non-inverting input end is larger than 0.1mV, the voltage of the non-inverting input end is increased through the parallel sliding resistor.
8. The passive wireless hydrogen sensing tag of claim 6, wherein the sensor conditioning circuit further comprises a fifth resistor, a sixth resistor and a DAC of the MCU; the output end of the DAC is connected with the REF of the instrument amplifier, the first end of the fifth resistor is connected with the output end of the instrument amplifier, the second end of the fifth resistor is connected with the first end of the sixth resistor, the second end of the sixth resistor is grounded, and the second end of the fifth resistor is also connected with the FB of the instrument amplifier.
9. The method for automatically adjusting the bridge balance of a passive wireless hydrogen sensing tag according to claim 8, comprising:
s1, firstly testing a Wheatstone bridge type, wherein the type comprises the following steps: the first output voltage is far greater than the second output voltage, and the first output voltage is far less than the second output voltage;
s2, inputting the larger one of the first output voltage and the second output voltage into the non-inverting input end of the instrumentation amplifier, and inputting the smaller one into the output end of the instrumentation amplifier;
s3, continuously collecting the output signal of the instrumentation amplifier after the MCU receives the leveling bridge command;
s4, if the output signal of the instrumentation amplifier is larger than the set bridge output balance value, executing the step S5; if the output signal of the instrumentation amplifier is smaller than the set bridge output balance value, executing step S6; otherwise, the Wheatstone bridge is considered to be balanced;
s5, the MCU outputs a larger digital signal to control the DAC to output a larger voltage; then returning to the step S3 to continue to collect the output signal of the instrumentation amplifier;
s6, the MCU outputs a small digital signal to control the DAC to output a small voltage; and then returns to step S3 to continue to collect the output signal of the instrumentation amplifier.
10. A passive wireless hydrogen sensing system comprising the passive wireless hydrogen sensing tag of claim 7; or a passive wireless hydrogen sensing tag according to claim 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811607863.XA CN109638942B (en) | 2018-12-27 | 2018-12-27 | Passive wireless hydrogen sensing label and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811607863.XA CN109638942B (en) | 2018-12-27 | 2018-12-27 | Passive wireless hydrogen sensing label and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109638942A CN109638942A (en) | 2019-04-16 |
| CN109638942B true CN109638942B (en) | 2020-05-19 |
Family
ID=66078124
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811607863.XA Active CN109638942B (en) | 2018-12-27 | 2018-12-27 | Passive wireless hydrogen sensing label and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109638942B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110610111B (en) * | 2019-09-16 | 2021-01-12 | 电子科技大学 | Remote passive wireless magnetic field quantity sensing system |
| CN114123481B (en) * | 2021-06-30 | 2023-06-27 | 国网福建省电力有限公司 | Transformer substation high-voltage cable oil-filled terminal space-isolation detection alarm system and method |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101833686A (en) * | 2010-04-30 | 2010-09-15 | 天津大学 | Semi-active label |
| CN102915463A (en) * | 2012-09-18 | 2013-02-06 | 盛世铸成科技(北京)有限公司 | Sensing passive tag |
| CN105262233A (en) * | 2015-10-09 | 2016-01-20 | 宁波力芯科信息科技有限公司 | Mobile equipment with wireless charging and discharging function and device |
| CN105318823A (en) * | 2015-11-03 | 2016-02-10 | 浙江大学 | Ultra-low power consumption passive structural strain monitoring device |
| CN105656167A (en) * | 2016-03-16 | 2016-06-08 | 苏州大学 | Passive wireless sensor node power supply circuit based on vibration energy harvesters |
| CN107016434A (en) * | 2017-05-18 | 2017-08-04 | 福建时雨科技有限公司 | A kind of electronic tag based on LPWAN and RFID technique |
| KR20180022513A (en) * | 2016-08-23 | 2018-03-06 | 엘지이노텍 주식회사 | Foreign Object Detection Method and Apparatus and System therefor |
| CN108648430A (en) * | 2018-05-11 | 2018-10-12 | 国网辽宁省电力有限公司电力科学研究院 | A kind of hyperfrequency take can and communication sensing device |
| WO2018191390A1 (en) * | 2017-04-13 | 2018-10-18 | Scott Technologies Inc. | Intrinsically safe battery |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101027345B1 (en) * | 2007-11-26 | 2011-04-11 | 주식회사 하이닉스반도체 | Electorstatic Discharge Device Capable of Controlling Pin Capacitance |
-
2018
- 2018-12-27 CN CN201811607863.XA patent/CN109638942B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101833686A (en) * | 2010-04-30 | 2010-09-15 | 天津大学 | Semi-active label |
| CN101833686B (en) * | 2010-04-30 | 2012-06-20 | 天津大学 | Semi-active label |
| CN102915463A (en) * | 2012-09-18 | 2013-02-06 | 盛世铸成科技(北京)有限公司 | Sensing passive tag |
| CN105262233A (en) * | 2015-10-09 | 2016-01-20 | 宁波力芯科信息科技有限公司 | Mobile equipment with wireless charging and discharging function and device |
| CN105318823A (en) * | 2015-11-03 | 2016-02-10 | 浙江大学 | Ultra-low power consumption passive structural strain monitoring device |
| CN105656167A (en) * | 2016-03-16 | 2016-06-08 | 苏州大学 | Passive wireless sensor node power supply circuit based on vibration energy harvesters |
| KR20180022513A (en) * | 2016-08-23 | 2018-03-06 | 엘지이노텍 주식회사 | Foreign Object Detection Method and Apparatus and System therefor |
| WO2018191390A1 (en) * | 2017-04-13 | 2018-10-18 | Scott Technologies Inc. | Intrinsically safe battery |
| CN107016434A (en) * | 2017-05-18 | 2017-08-04 | 福建时雨科技有限公司 | A kind of electronic tag based on LPWAN and RFID technique |
| CN108648430A (en) * | 2018-05-11 | 2018-10-12 | 国网辽宁省电力有限公司电力科学研究院 | A kind of hyperfrequency take can and communication sensing device |
Non-Patent Citations (2)
| Title |
|---|
| 《UHF RFID 标签芯片模拟射频前端设计》;李建等;《现代电子技术》;20100315(第6期);第8-11页 * |
| Injection current model of a MOS diode under charge-sharing mode readout operation;Chao-Wen Wu etal.;《IEEE Transactions on Electron Devices》;19930131;第40卷(第1期);第227-229页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109638942A (en) | 2019-04-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Phala et al. | Air quality monitoring system based on ISO/IEC/IEEE 21451 standards | |
| CN105656167B (en) | Passive wireless sensor node power circuit based on vibration energy collector | |
| CN109638942B (en) | Passive wireless hydrogen sensing label and system | |
| Reinhardt et al. | SmartMeter. KOM: A low-cost wireless sensor for distributed power metering | |
| CN101799358A (en) | Novel infrared-mark temperature control system with wireless transmission function | |
| Che et al. | A semi-passive UHF RFID tag with on-chip temperature sensor | |
| CN203981571U (en) | A kind of infrared gas sensor signal processing circuit | |
| CN110610111B (en) | Remote passive wireless magnetic field quantity sensing system | |
| CN103822667A (en) | Temperature-humidity acquisition system based on Bluetooth technology | |
| US20200350785A1 (en) | High sensitivity energy harvester | |
| CN207850459U (en) | A kind of water meter intelligence control system | |
| CN211602245U (en) | Torque measuring equipment | |
| CN104601008A (en) | Intelligent power supply system | |
| CN203573477U (en) | Effective wireless monitoring data receiving/transmitting device for grain drying equipment | |
| Meli et al. | A novel low power and low cost IoT wireless sensor node for air quality monitoring | |
| CN205301535U (en) | Battery status monitoring system and method | |
| CN111257662A (en) | Device and corresponding method applied to wireless charging equipment detection | |
| CN109857099A (en) | A kind of magnetic tracking sensor and the method for sensing using the sensor | |
| CN208256085U (en) | Water environment monitoring system based on NB-IoT | |
| CN202882899U (en) | Oilfield indicator based on ZigBee wireless sensor network | |
| Ishibashi et al. | Beat sensors IoT technology suitable for energy saving | |
| CN201788514U (en) | Novel RFID (radio frequency identification) tag micro-energy collection control device | |
| US20180081416A1 (en) | Electronic device and sensor device with low power consumption and related methods | |
| CN211318382U (en) | Gas monitor based on bluetooth Mesh | |
| Mihajlović et al. | Modular WSN node for environmental monitoring with energy harvesting support |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB03 | Change of inventor or designer information |
Inventor after: Li Gang Inventor after: Li Zhenbing Inventor after: Guan Debin Inventor after: Tian Xianqing Inventor after: Wen Guangjun Inventor after: Hu Wei Inventor after: Zhang Youpeng Inventor before: Li Gang Inventor before: Li Zhenbing Inventor before: Wen Guangjun Inventor before: Hu Wei Inventor before: Zhang Youpeng |
|
| CB03 | Change of inventor or designer information | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20200106 Address after: 611737 No. 2006 West Yuan Road, Chengdu high tech Zone (West District), Sichuan Applicant after: UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY Applicant after: Inst. of Chemical Material, Chinese Inst. of Engineering Physics Address before: 611731 Chengdu province high tech Zone (West) West source Avenue, No. 2006 Applicant before: UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |