單片機(jī)外文翻譯--一種基于單片機(jī)的房間溫度檢測(cè)系統(tǒng)（英文）

1、 International Journal of Computer Applications (0975 – 8887) Volume 53– No.1, September 2012 7 A Microcontroller- based Room Temperature Monitoring System Theophilus Wellem Department of Information Systems Satya Wa

2、cana Christian University Salatiga, Indonesia, 50711 Bhudi Setiawan Department of Informatics Satya Wacana Christian University Salatiga, Indonesia, 50711 ABSTRACT Monitoring the temperature of a computer server room is

3、 a critical task to ensure the performance of the server is not disturbed by excessive room temperature. In this paper, we designed and implemented a microcontroller-based room temperature monitoring system using Atm

4、el ATmega8535 microcontroller and National Semiconductor's LM35 temperature sensor. The system is equipped with a Wavecom GSM modem to send and receive text message (SMS) and relay board to control electronic

5、equipment. The experiment results show that our system works as expected. The system raises an alarm and send an alert message to administrator when the room temperature is above threshold, which is 28°C. Gener

6、al Terms Design, Experimentation Keywords Microcontroller, temperature sensor, server room temperature 1. INTRODUCTION Computer server room plays an important role in the IT infrastructure of an organization to suppo

7、rt the organization's computer network or other IT-related tasks. Therefore, monitoring the temperature of a computer server room is a critical task to ensure that the performance of the server is not disturbed b

8、y excessive room temperature. Generally, the daily computer server room's temperature is affected by several factors such as, the server room size, number of server inside the room, and the room's air conditio

9、ning system. Nevertheless, a system that capable to warn the server administrator regarding the server room temperature will be very useful in case of there is any excessive temperature. This paper presents our desig

10、n and implementation of a microcontroller-based system for monitoring server room temperature. We use Atmel AVR ATmega8535 microcontroller and LM35 temperature sensor as the main components of the system. Liquid

11、Crystal Display (LCD) and buzzer are used to display the server room temperature and as an alarm, respectively. In order to alert the server administrator, the system is equipped with a GSM modem to immediately send

12、text message if the server room temperature is above a predefined threshold. A relay board is also connected to the microcontroller to control other electronic appliances inside the server room. The remainder of this

13、 paper is organized as follows. In Section 2, we provide a short background on microcontroller, specifically the Atmel ATmega8535 microcontroller, and also the LM35 temperature sensor. The design and implementation o

14、f the system is described in Section 3. Section 4 provides the results of our experiments and discussion. Finally, Section 5 concludes the paper. 2. BACKGROUND Microcontroller can be regarded as a single-chip special-

15、purpose computer dedicated to execute a specific application. As in general-purpose computer, microcontroller consists of memory (RAM, ROM, Flash), I/O peripherals, and processor core. However, in a microcontroller, t

16、he processor core is not as fast as in general purpose-computer, the memory size is also smaller. Microcontroller has been widely used in embedded systems such as, home appliances, vehicles, and toys. There are sever

17、al microcontroller products available in the market, for example, Intel's MCS-51 (8051 family), Microchip PIC, and Atmel's Advanced RISC Architecture (AVR). We discuss Atmel ATmega8535 and LM35 temperature se

18、nsor in this section. 2.1 Atmel ATmega8535 ATmega8535 is an 8-bit AVR microcontroller. It has a 16 MHz AVR CPU, 8KB Flash, 512 Bytes EEPROM, and 512 Bytes internal SRAM. The other on-chip peripherals include two 8-bi

19、t timers/counters, one 16-bit timer/counter, 8-channel 10-bit analog-to-digital (ADC) and 32 programmable I/O lines, PORTA to PORTD, where each port has 8 lines. This microcontroller is available in 40-pin PDIP, 44-pi

20、n TQFP/MLF, and 44-pin PLCC packages. Details of ATmega8535 microcontroller are described in [1]. 2.2 LM35 Temperature Sensor The LM35 is a temperature sensor, whose output voltage is linearly proportional to the Ce

21、lsius temperature. This sensor has linear output and low output impedance make it easy for connecting it to the readout circuitry [2]. Three pins, +Vs, GND, and Vout are defined for the sensor. When used as a basic t

22、emperature sensor (2°C to 150°C), any change in temperature by 1°C will be converted to 10 mV or the output voltage (Vout) = 0 mV + 10 mV/°C. 3. RELATED WORK Zhu and Bai [3] proposed a system for m

23、onitoring the temperature of electric cable interface in power transmission, based on Atmel AT89C51 microcontroller. The system consists of a central PC machine, host control machines, and temperature collectors. Sev

24、eral temperature collectors are connected to a host control machine through RS-485 communication network, and the host control machine communicates and exchanges data with the central PC machine using General Packet

25、Radio Service (GPRS) connection. The temperature collector itself consists of sensor temperatures (Maxim's DS18B20, 1-wire digital thermometer), decoders, and other circuits for interfacing International Journ

26、al of Computer Applications (0975 – 8887) Volume 53– No.1, September 2012 9 Fig 3: Room temperature monitoring system then is checked for control command or other command such as, command to request the current room tem

27、perature and relay (PORTC) status. After execution of both kind of command, system will reply with a message to confirm the execution is complete. The purpose of the threshold increment is to avoid the system sending

28、 message continuously to the administrator. Therefore, the subsequent message only sent when the temperature is increase by 1°C. After sending message and activating buzzer, system will back to modem check and re

29、ad the temperature again. Here, the buzzer is deactivated (if it is activated) and the threshold is set back to 28°C (if it is already incremented). 4.1 Hardware Photograph of the system is shown in Fig 3. The to

30、p part and bottom part of the figure shows the relay board and microcontroller board, respectively. As shown, the GSM modem is connected to the board via DB-9 connector. 4.2 Software The software has four main parts

31、: 1) read the temperature from ADC, 2) send text message, 3) receive text message, and 4) parsing text message and command selection. Code 1 shows the ADC read part. The voltage value is read from PORTA(0)/ADC(0) the

32、n stored in Adc_vlt variable. This value then, after some computations, is assigned to Vlt variable. The value of Vlt variable is the value to be compared to the predefined threshold. Therefore, if Vlt value is great

33、er than 28°C, the system will raise the alarm. Code 1. Read data from ADC Code for sending text message is shown in Code 2. AT command [10], AT+CMGS is used to send text message. Number variable contains the admin

34、istrator phone number and the message is ”Warning!! Room Server Temp. Now” followed by the temperature value. The Chr(26) or CTRL-Z is used to start the sending process. This code part will be called when the Vlt valu

35、e is greater than 28°C. Code for receiving (read) text message is almost the same with Code 2, except it uses the AT+CMGR command. Code 2. Send text message After the text message parsing process, command selectio

36、n part is simply done using the conditional structure (if...elseif). The code part is shown in Code 3 below. As shown in the code, if the system receives “Status” command, then it will execute another procedure calle

37、d Status. This command is used to request the current room temperature and state of PORTC1-PORTC5 (connected to relay board, whether it is ON or OFF). The command “P1ON” is used to change the state of PORTC1 to ON. T

38、herefore, the electronic appliance connected to one of the relays is turned on. Otherwise, if the command is “P1OFF”, the appliance is turned OFF. There are several commands defined for the system. These commands is

39、listed in Table 1. Code 3. Command selection process Table 1. List of command and its description Command Description Temp Request current room temp. Status Request the state of PORTC(1-5) Number Wait 1 Print “Warn

40、ing!! Room Server Temp. Now “ ; Vlt ; “'C“ Print Chr(26) '... other code... Thres = 28 '... other code... Data_adc = Getadc(0) Adc_vlt = Data_adc / 1024 Adc_vlt = Adc_vlt * 500 Vlt = Fusing(Adc_vlt