CN203191083U - Wireless temperature measuring sensor with ultralow power consumption - Google Patents

Abstract

An ultra-low power consumption wireless temperature measuring sensor belongs to the field of measurement. It sets a random power supply to provide power for the temperature sensor, single-chip microcomputer and wireless transmission module; its random power supply is a lithium battery; its single-chip microcomputer is a low-power single-chip microcomputer; its wireless transmission module is a Zigbee wireless communication module; Connect with the signal output terminal of the temperature sensor, and connect with the signal input terminal of the Zigbee wireless communication module through the serial bus; connect the power input terminal of the low-power single-chip microcomputer with the output terminal of the lithium battery power supply; Connect the power supply; set an electronic switch circuit between the power input terminal of the wireless transmission module and the output terminal of the lithium battery power supply; the input terminal of the electronic switch circuit is connected to the output terminal of the lithium battery power supply, and its output terminal is connected to the power supply input terminal of the wireless transmission module. , the control terminal of the electronic switch circuit is connected with the I/O port of the low-power single-chip microcomputer. The device can be widely used in the field of equipment status monitoring in power systems.

Description

A wireless temperature sensor with ultra-low power consumption

technical field

The utility model belongs to the field of measurement, in particular to an on-line temperature measuring device for power equipment. the

Background technique

When the power equipment is working, the normal heating of each component should not exceed its maximum allowable temperature, so as to ensure safe operation. On-line temperature monitoring of the operating status of power equipment can detect equipment abnormalities in time and take measures to avoid accidents. the

Poor electrical contact conditions at the conductive connections and sockets of electrical equipment are important reasons for excessive temperature at these locations. Therefore, the conductive connection and socket are the main parts of online monitoring. the

There are mainly two types of online temperature monitoring methods: non-contact infrared radiation and contact temperature measurement using heat-sensitive devices. Since the non-contact infrared sensor is greatly affected by the environment, humidity, and atmospheric pressure, the infrared radiation cannot be accurately measured when it is blocked, and its use has great limitations. The contact sensor is directly in contact with the temperature measurement point, and is less disturbed by environmental factors, and can realize accurate and rapid temperature detection. the

Insufficiency of existing contact temperature measurement schemes: contact temperature measurement schemes usually use thermocouples, optical fiber sensors, and resistive sensors as temperature measurement sensors. The measurement at room temperature requires cold end compensation. In actual measurement, when the distance between the hot end and the cold end is far away, a compensation wire is also required; How to install and route the fiber optic sensor is very problematic. The optical fiber transmission signal scheme is not easy to achieve complete isolation of high and low potentials. When the transmitting end is installed with a high voltage end, the problem of ground insulation cannot be solved; using a resistive sensor for direct contact measurement, It is a good way to transmit signals with wires at high potentials, simply use air gaps to isolate high and low potentials, and transmit temperature signals through infrared photoelectric conversion. However, the infrared emitting and receiving tubes are exposed, and long-term use will cause dust and pollution, making signal transmission reliable. It is also a difficult problem to solve the problem that the gradual deterioration of the performance affects the measured value. In addition, it must be professionally installed and debugged on site. The convenience of use is not ideal. the

Therefore, the difficulty of the existing online temperature monitoring device is that it is necessary to effectively solve the problem of high voltage intrusion into the low voltage system and ensure that the temperature sensor can work normally for a long time (at least longer than one equipment maintenance cycle). the

Utility model content

The technical problem to be solved by the utility model is to provide a wireless temperature measuring sensor with ultra-low power consumption, which uses a wireless temperature sensor to monitor the temperature of the monitoring point, sends the temperature data to the outside through a wireless transmission module, and uses a timing mechanism. Under normal circumstances, it is in an ultra-low power sleep state, and cuts off the power supply to the temperature sensor and the wireless transmitter module to reduce its power consumption. the

The technical scheme of the utility model is to provide a wireless temperature measuring sensor with ultra-low power consumption, including a temperature sensor, a single-chip microcomputer and a wireless transmitting module, and is characterized in that: a random power supply is provided to provide the temperature sensor, the single-chip microcomputer and the wireless transmitting module Power supply; the random power supply includes a lithium battery; the single-chip microcomputer is a low-power single-chip microcomputer; the wireless transmission module is a Zigbee wireless communication module; the low-power single-chip microcomputer is output by the signal of the serial bus and the temperature sensor Terminal is connected, and is connected with the signal input end of Zigbee wireless communication module through serial bus; The power input end of described low-power single-chip microcomputer is correspondingly connected with the power output end of lithium battery; Described low-power single-chip microcomputer is through I/O The port is connected to the power supply end of the temperature sensor; between the power input end of the Zigbee wireless communication module and the power output end of the lithium battery, an electronic switch circuit is set; the input end of the electronic switch circuit corresponds to the power output end of the lithium battery Connect, its output terminal is correspondingly connected with the power supply input terminal of Zigbee wireless communication module, the control terminal of described electronic switch circuit is connected with the I/O port of low-power single-chip microcomputer. the

Specifically, the electronic switch circuit includes a PMOS switch tube D1, the source of the PMOS switch tube D1 is correspondingly connected to the power output end of the lithium battery, and its drain is correspondingly connected to the power input end of the Zigbee wireless communication module. The gate is connected to the I/O port of the low-power microcontroller. the

Further, the output terminal of the lithium battery power supply is connected in parallel with an energy storage capacitor. the

Compared with prior art, the utility model has the advantages of:

1. Adopt Zigbee wireless network data transmission method to solve the problem of reliable isolation between high voltage end and low voltage system;

2. Adopt the power supply scheme of lithium battery and energy storage capacitor, and control whether the Zigbee wireless communication module enters the working state through the low-power single-chip microcomputer, so as to minimize the power consumption and prolong the service life of the wireless temperature sensor;

3. The output of the wireless temperature sensor is a digital signal, which is directly interfaced with the CPU through the serial bus. Compared with sensors with analog output such as thermocouples and thermal resistances, there is no need for calibration and correction, so the stability is extremely high. the

Description of drawings

Fig. 1 is the schematic diagram of circuit module structure of the present utility model;

Fig. 2 is the embodiment circuit diagram of the utility model single-chip microcomputer;

Fig. 3 is the embodiment circuit diagram of random power supply of the present utility model;

Fig. 4 is the embodiment circuit diagram of electronic switch circuit of the present invention and Zigbee wireless communication module;

Fig. 5 is a circuit diagram of an embodiment of the temperature sensor of the present invention. the

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described. the

In Fig. 1, the ultra-low power consumption wireless temperature measuring sensor of the technical scheme of the present utility model comprises temperature sensor S1, single-chip microcomputer U1 and wireless transmitting module Z1, is characterized in that: a random power supply is set, is temperature sensor, single-chip microcomputer and wireless transmitting module The module provides power; the random power supply includes a lithium battery B1. the

The single-chip microcomputer is a low-power single-chip microcomputer; the wireless transmitting module is a Zigbee wireless communication module. the

Described low-power single-chip microcomputer is connected with the signal output end of temperature sensor by serial bus, and is connected with the signal input end of Zigbee wireless communication module through serial bus;

The power input end of the low-power single-chip microcomputer is correspondingly connected with the power output end of the lithium battery;

Described low-power single-chip microcomputer is connected with the power end of temperature sensor through I/O port;

An electronic switch circuit is set between the power input end of the Zigbee wireless communication module and the power output end of the lithium battery;

The input end of described electronic switch circuit is correspondingly connected with the power output end of lithium battery, and its output end is correspondingly connected with the power input end of Zigbee wireless communication module, and the control end of described electronic switch circuit is connected with the I/O of low power consumption single-chip microcomputer port connection. the

Specifically, the electronic switch circuit includes a PMOS switch tube D1, the source of the PMOS switch tube D1 is correspondingly connected to the power output end of the lithium battery, and its drain is correspondingly connected to the power input end of the Zigbee wireless communication module. The gate is connected to the I/O port of the low-power microcontroller. the

Further, the output terminal of the lithium battery power supply is connected in parallel with an energy storage capacitor C1. the

It can be seen from the figure that the single-chip microcomputer U1 is the core of the system, it supplies power to the temperature sensor S1 through the I/O pin, and reads the real-time temperature value of the temperature sensor through the serial bus (SPI). When the difference between the second collection value is greater than the set value, the single-chip microcomputer controls the I/O pin to turn on the switch tube D1 (PMOS switch), thereby supplying power to the wireless communication module Z1 (Zigbee module), and through the serial bus (SPI ) to send the temperature value wirelessly. the

The main chip models are as follows:

B1 is lithium ion battery;

C1 is a surface mount tantalum capacitor, which is used to provide a large current at the moment of transmission;

D1 is the PMOS switch TPS1100;

Z1 is the SZ05-ZBEE series Zigbee wireless communication module;

U1 is Microchip's ultra-low power microcontroller PIC24F16KL402;

S1 is the digital temperature sensor ADT7410 of ADI Company. the

The temperature sensor of this system adopts a digital temperature sensor. Since the output of the sensor is a digital signal, it is directly connected to the CPU through a serial bus. Compared with sensors with analog output such as thermocouples and thermal resistances, there is no need for calibration and correction, so it is stable. Extremely high. the

Zigbee equipment is a low-power equipment, its transmission output power is 0~3.6dBm, the communication distance is usually 30~70m, and it has the ability of energy detection and link quality indication. According to these detection results, the device can automatically adjust the transmission power. Under the condition of the quality of the communication link, the energy consumption of the equipment is minimized. the

The ZigBee module is a module prepared for product development with high block speed, high efficiency, and stable application. It hides the complex processes such as external devices and high-frequency wiring that must be connected to the ZigBee chip. Users do not need to understand radio frequency knowledge. It can be used in the form of a chip, which greatly reduces the difficulty of hardware design of the ZigBee network. the

Regarding the ZigbBee module, there are already many mature commercially available products, and the common Zigbee wireless signal transmission platform is composed of an 8-bit or 16-bit single-chip microcomputer and a Zigbee radio frequency chip. With the development of chip design, a wireless single-chip microcomputer has appeared at present, which integrates the processor module and the radio frequency module in the same chip. Ti-Chipcon's CC2430 is like this. CC2430 integrates Zigbee RF front-end, ROM and 8051 microcontroller in one chip, and its size is only 7mm×7mm, which makes the equipment highly integrated, with few peripheral components and very small appearance. Small; in receiving and transmitting modes, the current consumption is lower than 27mA or 25mA respectively, and supports four sleep mechanisms, which can greatly reduce power consumption; CC2430 works in the free frequency band of 2.4GHz, and the chip price is relatively low, and the cost of use is very low Low, so CC2430 is in line with the design requirements of Zigbee wireless data signal transmission network platform. the

For the specific working principles and application circuits of various ZigBee modules, you can refer to the product information of each chip/module manufacturer, which will also provide the standard application circuit of each chip and the optimal parameters of the corresponding components, so further information is here No more narration. the

For the specific construction of the ZigBee wireless network module, you can also refer to the relevant content in the ZigBee module ZICM2410 Application Development Guide on "Embedded Industrial Control Network" (www.embedcontrol.com), which will not be described here. the

Since the wireless temperature sensor is powered by a lithium battery, in order to prolong the battery life, an ultra-low power consumption design method is adopted in the circuit design, mainly including the following points:

(1) The system selects Microchip's ultra-low-power single-chip microcomputer as the core, and its power consumption in running and sleeping states has reached a very low level. the

(2) Due to the large power consumption of temperature acquisition and wireless transmission, in the design, a timing mechanism is adopted, and the CPU is in an ultra-low power sleep state under normal circumstances, and the power supply to the temperature sensor and wireless transmission module is cut off. Make the static power consumption below 0.7uA. When the timing time is up (the default time is 30 seconds), the CPU wakes up and collects the temperature. The temperature value collected this time is compared with the previous temperature value. If it exceeds the set threshold (0.5 degrees by default), the wireless transmitter module is turned on. Part of the power supply, send data, if it does not exceed the threshold, it will be sent 8 times in total. the

(3) The system chooses an ultra-low power consumption digital temperature sensor. Its typical power consumption is 7uW. The power supply is realized through the I/O pin of the CPU. It is powered only when the temperature is collected, and it is not powered at other times, so no power is generated. power consumption. the

(4) The wireless transmitting module is the part with the largest power consumption in the system. When the data is not sent, its power supply is cut off, and no power consumption will be generated. The system software adopts the change threshold value and sends it immediately, otherwise Send 1 every 8th to minimize power consumption without affecting data update. the

(5) The lithium battery and energy storage capacitor of the system are ultra-low leakage models. the

(6) An energy storage capacitor is set to provide a large current at the moment when the wireless transmitting module transmits a wireless signal, reducing the high current working time of the lithium battery and further prolonging its service life. the

Due to the above-mentioned series of low-power design measures, the average power consumption of the system can reach less than 2uA, and the 1AH lithium battery can run for more than 8 years (the impact of lithium battery self-discharge has been considered). the

Among Fig. 2 to Fig. 5, have provided the circuit diagram of embodiment of the utility model single-chip microcomputer, random power supply, electronic switch circuit and Zigbee wireless communication module and temperature sensor, as can be seen from the figure, single-chip microcomputer U1 is given temperature sensor by I/O pin. S1 supplies power, and reads the real-time temperature value of the temperature sensor through the serial bus (SPI). When the difference between the collected temperature value and the last collected value is greater than the set value, the microcontroller controls the switch through the I/O pin. The tube D1 (PMOS switch) is turned on, so as to supply power to the wireless communication module Z1 (Zigbee module), and send the temperature value wirelessly through the serial bus (SPI). the

The industry standard drawing and marking are used in the figure, and those skilled in the art should be able to understand and understand its meaning without any meaning, so the specific connection relationship between each component will not be described in detail here, please refer to the figure for details. The pin numbers and letter labels in . the

Since the utility model adopts a wireless temperature sensor to monitor the temperature of the monitoring point, and transmits the temperature data to the outside through wireless communication, the problem of reliable isolation between the high-voltage end and the low-voltage system is solved; the power supply scheme of a lithium battery and an energy storage capacitor is adopted, and Whether the Zigbee wireless communication module enters the working state is controlled by a low-power single-chip microcomputer, so as to minimize power consumption and prolong the service life of the wireless temperature sensor; directly interface with the CPU through the serial bus, no calibration, no correction, so stable Extremely high. the

The utility model can be widely used in the field of state monitoring of power system equipment. the

Claims (3)

1. A wireless temperature measuring sensor with ultra-low power consumption, comprising a temperature sensor, a single-chip microcomputer and a wireless transmitter module, is characterized in that: Set a random power supply to provide power for the temperature sensor, microcontroller and wireless transmitter module; Described random power supply comprises lithium battery; Described single-chip microcomputer is a low-power consumption single-chip microcomputer; Described wireless transmitting module is Zigbee wireless communication module; Described low-power single-chip microcomputer is connected with the signal output end of temperature sensor by serial bus, and is connected with the signal input end of Zigbee wireless communication module through serial bus; The power input end of the low-power single-chip microcomputer is correspondingly connected with the power output end of the lithium battery; Described low-power single-chip microcomputer is connected with the power end of temperature sensor through I/O port; An electronic switch circuit is set between the power input end of the Zigbee wireless communication module and the power output end of the lithium battery; The input end of described electronic switch circuit is correspondingly connected with the power output end of lithium battery, and its output end is correspondingly connected with the power input end of Zigbee wireless communication module, and the control end of described electronic switch circuit is connected with the I/O of low power consumption single-chip microcomputer port connection. 2. The ultra-low power consumption wireless temperature sensor according to claim 1, wherein the electronic switch circuit includes a PMOS switch tube D1, the source of the PMOS switch tube D1 is connected to the power output terminal of the lithium battery Correspondingly connected, its drain is correspondingly connected with the power input end of the Zigbee wireless communication module, and its gate is connected with the I/O port of the low-power single-chip microcomputer. 3. The wireless temperature measuring sensor with ultra-low power consumption according to claim 1, characterized in that the output terminal of the lithium battery power supply is connected to an energy storage capacitor in parallel.

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