CN102279011A - A low power consumption temperature and humidity recorder - Google Patents

Abstract

The invention discloses a low-power-consumption temperature and humidity recorder. The low-power consumption temperature and humidity recorder comprises a microcontroller (U1), a plurality of external storages, a temperature and humidity SENSOR (SENSOR1), a universal serial bus chip (U6) and a universal serial interface (J1); the microcontroller (U1) is connected with a temperature and humidity SENSOR (SENSOR1) and an external memory through an I/O port, and the universal serial port interface (J1) is connected with the microcontroller (U1) through a universal serial port bus chip (U6).

Description

A low power consumption temperature and humidity recorder

technical field

The invention relates to a portable temperature and humidity recorder capable of timing, low power consumption, small volume and high reliability.

Background technique

The temperature and humidity recorder is a miniature measuring instrument, which can regularly and automatically record the temperature and humidity introduced by the measured environment, and store the measurement results. By connecting with a computer, the measurement data can be analyzed. Since this instrument does not require human intervention, it can also be used in some environments that cannot be monitored manually, such as air conditioning system debugging, drying and other occasions. It is very important to accurately transmit the saved test results to the connected computer to realize later data analysis. With the decline of memory prices and the richness of product categories, large-capacity non-volatile memories have gradually begun to be widely used. Like this, what follows is the increase of transmission time and data. The power consumption of the temperature and humidity recorder in the prior art is all relatively large, and the transmission rate is also relatively slow. Therefore, it is very unfavorable when the recorder is used for a long time. . In addition, most of the existing recorders use analog temperature and humidity sensors. In this way, it is necessary to add an analog-to-digital conversion circuit in the processor part or in the circuit, which increases the power consumption of the system; Battery life in battery-sensitive devices is greatly reduced.

Contents of the invention

The purpose of the present invention is to make up for the deficiencies in the prior art, and provide a temperature and humidity recorder which is convenient to connect with a computer, has large capacity, high measurement accuracy and low power consumption.

Technical solution: Provide a low-power temperature and humidity recorder. The low power consumption temperature and humidity recorder includes a microcontroller U1, several external storage devices, a temperature and humidity sensor SENSOR1, a universal serial bus chip U6 and a universal serial interface J1.

The microcontroller U1 is connected to the temperature and humidity sensor SENSOR1 and an external memory through an I/O port, and the universal serial interface J1 is connected to the microcontroller U1 through a universal serial bus chip U6.

Wherein, the microcontroller U1 adopts MSP430F437 chip, the DATA pin of the temperature and humidity sensor SENSOR1 is connected with the 56 pins of the microcontroller U1, and is connected with the 62 pins of the microcontroller U1 through the first resistor R1; The SCK pin of the humidity sensor SENSOR1 is connected to the 61 pin of the microcontroller U1; the VDD pin of the temperature and humidity sensor SENSOR1 is connected to the 62 pin of the microcontroller U1.

The TXD pins of the universal serial bus chip U6 are respectively connected with pins 53 and 55 of the microcontroller U1,

The RXD pin of the universal serial bus chip U6 is connected with the 54 pin of the microcontroller U1.

The VCUS pin of the universal serial port interface J1 is connected with the REGIN and VBUS pins of the universal serial bus chip U6 respectively; the D-pin of the universal serial port interface J1 is connected with the D-pin of the universal serial bus chip U6; the universal serial port interface The D+ pin of J1 is connected with the D+ pin of the universal serial bus chip U6.

Technical effect: The microcontroller is connected to the temperature and humidity sensor and the external memory through the ordinary I/O port, and provides the clock signal for the operation of the two devices by controlling the level of the I/O port to realize the temperature and humidity measurement. The measured data is stored in an external storage device at a good time. In actual application, the recorder is connected to the computer through the USB transmission chip interface, and the parameters of the recorder (system clock, recording time interval and start recording method) are set through the VC program on the host computer (the PC controls and the single-chip microcomputer through VC) Communication), there are three ways for the recorder to start recording: open at the current time, open at a certain time in the future, set sampling time, and measure in real time. After the setting is completed, disconnect the recorder from the computer, and the recorder can start measuring and recording temperature and humidity data according to the preset opening mode. After the data measurement is over, retrieve the recorder and reconnect it to the PC. Through the VC program on the PC, the temperature and humidity data recorded in the EEPROM can be exported to form Excel tables and data curves for analysis and processing.

Description of drawings

Fig. 1 is a circuit diagram of a low power consumption temperature and humidity recorder according to a specific embodiment of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to Fig. 1, the temperature and humidity recorder in this embodiment mainly includes a microcontroller U1, non-volatile memories U2, U3, U4, U5, a universal serial bus chip U6, a universal serial interface J1, and a temperature and humidity sensor module SENSOR1.

Among them, the microcontroller adopts TI's low-power single-chip microcomputer, which can independently control the direction of I/O pins, and has an A/D converter with 12-bit resolution. It can run in dual clock mode, and the external crystal oscillator adopts 32.768kHz crystal oscillator to provide accurate real-time clock for the system. This kind of single-chip microcomputer has ultra-low power consumption wake-up function, and has an enhanced USART module, which can automatically wake up the device through the serial port, so as to facilitate the low power consumption design of the system.

The sensor module adopts the SHT1X digital sensor of Shengshi Ruien Company. SHT1X is a single-chip integrated digital temperature and humidity sensor. All signal conditioning is completed inside the chip. It uses 1C bus to realize communication, completes data and clock transmission, and directly outputs digital signals. The sensor has 14bit resolution for temperature measurement and 12bit resolution for relative humidity. This not only saves the I/O port lines of the single-chip microcomputer, but also reduces the A/D devices and reduces the cost. To connect MSP430F435 to SHT11, just use 2 I/O lines as data line DATA and clock line SCK respectively, and connect a pull-up resistor to the DATA end, and connect a decoupling capacitor to the VDD and GND ends , through the corresponding software design, the data collection and transmission can be completed.

The external memory for collecting data is Microchip's 24LC512 type. This chip supports 2-wire serial interface and can store up to 64K data with a large storage capacity. Since the storage and measurement data are not synchronized, the EEPROM can share the SCK pin with the sensor. In addition, an I/O port of the microcontroller is selected as the DATA~I pin, and the pin must also be connected to a pull-up resistor.

The universal serial bus sampling is CP2103, which is a highly integrated USB-to-UART bridge, providing a simple solution to realize RS232-to-USB with minimal components and PCB space. The chip includes a USB 2.0 full-speed function controller, USB transceiver, oscillator and asynchronous serial data bus (UART) with all modem control signals, all functions are integrated in a 5mm X5mm MLP-28 package IC. No other external USB components are required in the The on-chip EEPROM can be used for OEM-customized storage for data such as USB vendor code, product code, product description text, power tag, version number, and device serial number.

EEPROM can be programmed on the application board via USB, which makes it possible to program it during product manufacturing and debugging. The CP2101 can be easily used to implement an effective COM port using the device driver provided by CYGNAL free of charge.

The duty-free utility COM port (VCP) device driver provided by Cygnal allows a CP2101-based product to be used as a COM port of a PC. The UART interface of CP2101 handles all RS232 signals including control and handshaking signals so the existing system firmware does not need to be changed. In many existing RS232 designs, all that is required to upgrade from RS232 to USB is to replace the RS232 level converter with the CP2101. The principle of device selection is to reduce the power consumption as much as possible and reduce the volume of the recorder on the premise of realizing the functions of the system. The operating frequency of the microcontroller has a great influence on power consumption, the higher the frequency, the greater the power consumption. When using 32kHz crystal oscillator and 3V working voltage, the typical working current of msp430 series single-chip microcomputer is only 15μA. Using 32.768kHz external crystal oscillator, it provides real-time clock for the system in sleep mode, which greatly reduces the power consumption of the system.

Referring to Figure 1, this embodiment: the system is powered by a 3V button battery, and the data collected by the temperature and humidity sensor is converted and read by the MSP430F435 microcontroller and stored in the EEPROM, and the current measurement time is written at the same time, and the current temperature and humidity data is recorded. Realize the requirement of real-time recording, when it is connected to the computer, the data can be read out through the host computer software, and the temperature and humidity change curve can be displayed. It realizes small size, low power consumption, high precision, and long-time measurement, with a typical service life of 2 years.

The above content is a further detailed description of the present invention in combination with preferred technical solutions, and it cannot be assumed that the specific implementation of the invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, simple deduction and substitutions can be made without departing from the concept of the present invention, which should be regarded as the protection scope of the present invention.

Claims (2)

1. a kind of low power consumption temperature and humidity recorder, it is characterized in that, described low power consumption temperature and humidity recorder comprises microcontroller (U1), some external storages, temperature and humidity sensor (SENSOR1), universal serial port bus chip ( U6) and universal serial interface (J1); The microcontroller (U1) is connected to the temperature and humidity sensor (SENSOR1) and an external memory through an I/O port, and the universal serial interface (J1) is connected to the microcontroller (U1) through a universal serial bus chip (U6). 2. A kind of low power consumption temperature and humidity recorder according to claim 1, is characterized in that, described microcontroller (U1) adopts MSP430F437 chip, the DATA pin of described temperature and humidity sensor (SENSOR1) and microcontroller The 56 pins of (U1) are connected, and are connected with the 62 pins of the microcontroller (U1) through the first resistor (R1); the SCK pins of the temperature and humidity sensor (SENSOR1) are connected with the 61 pins of the microcontroller (U1) ; The VDD pin of the temperature and humidity sensor (SENSOR1) is connected with the 62 pins of the microcontroller (U1); The TXD pin of the universal serial bus chip (U6) is connected with the 53,55 pins of the microcontroller (U1) respectively, and the RXD pin of the universal serial bus chip (U6) is connected with the 54 pins of the microcontroller (U1) ; The VCUS pin of the universal serial interface (J1) is connected with the REGIN, VBUS pins of the universal serial bus chip (U6) respectively; the D-pin of the universal serial interface (J1) is connected with the D-pin of the universal serial bus chip (U6). pin connection; the D+ pin of the universal serial interface (J1) is connected with the D+ pin of the universal serial bus chip (U6).

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