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    Project on Temperature sensor for PC based on AT89C2051 or 8051 microcontroller

    hi all
    i need helpfor temprature controller based on 8051 with type j
    sensor any one can help me for simple hardwre and support me
    at software
    thanks all

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  2. #2
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    temperature sensor 8051 c program

    you can visit this site: www.pjrc.com



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    8051 help

    hi


    i got information about project on Temperature sensor for PC based on AT89C2051 microcontroller ,which am sharing with you here.


    Temperature Sensor - Collecting Temperature Data and Sending it to a PC
    This tutorial shows how to use a microcontroller to interface to a Dallas 1620 temperature sensor IC. This value can be used by the microcontroller directly or, as in this tutorial, sent to the PC. It uses the AT89C2051 microcontroller to collect data and send it to the PC. A MAX232CPE chip is used to convert the signals from and to RS232 levels for sending and receiving through the serial port. For more details on some aspects of the hardware, refer to the Data Collection tutorial.

    The Temperature Sensor

    To get a temperature reading we use the Dallas DS1620 integrated circuit. It is an 8 pin chip that has a built in system that measures the temperature and converts the reading into a 9 bit binary value. It has an accuracy of 0.5 degrees C and a range of -55 to 125 C. The temperature reading is updated about once per second. A digital interface is included in the chip that allows us to connect a microcontroller to the chip and send it commands and receive the temperature data back from the chip.



    The temperature is received in the microcontroller as 2 bytes. The second byte only contains a sign bit to signify whether the temperature is above or below 0 degrees Celsius. For this project we are ignoring the sign bit and just using the first byte. We will assume the temperature is above 0 degrees C (32 F). The value in the first byte is the number of 0.5 degree increments. For example, if we get a 1 then the temperature is 0.5 degrees C. If we get a 10 then the temperature is 5 degrees C. The range of possible values is 0 to 250 which is 0 to 125 degrees C. (The DS1620 can also measure down to -55 degrees C).

    For this project we are only using the serial interface pins, 1, 2, and 3. The pins 5, 6, and 7 have other functions that are used in thermostats. They change from 0 to 1 when a certain temperature is reached (for example, to turn a heater on and off). For more details about this and the details of the DS1620, click here to get the data sheet.

    Refer to the diagram below to build the circuit. The Data Collection Tutorial has more detailed instructions on using the MAX232 chip.



    The Software

    The basic process of compiling an assembly language program and loading it into the microcontroller was covered in the first microcontroller project. The 2051 assembly language program for this project is temp.asm. It is included on the software CD that comes with the kit. You will need a device programmer such as the PG302 to download the program into the 2051.

    The temp.asm program demonstrates a serial interface with another chip. This is a fairly common situation. The serial interface can be created with only 2 or 3 pins. There is usually a clock line and a data line. In this case there is also a control line called Reset that acts as a control signal, signaling the begin and end of each communication sequence. The clock is generated by the microcontroller, giving the microcontroller complete control over the bit by bit transmission. In this case the microcontroller is responsible for initiating each exchange of data over the serial link. Another possible configuration (for example, 2 microcontrollers linked together) could allow the device on either end to initiate an exchange.

    Make sure the power is off to the circuit you have built. Connect the circuit to the PC's serial port, Comm1. Connect the power to the breadboard. The circuit should send a continuous stream of values to the PC. To see the values on the PC, try this sample program. After downloading, double click it to extract the files and then run setup.exe to install it. The sample program receives the original value and displays it on the screen. It also converts the value to Celsius and Fahrenheit and displays those. The source code for the sample program (written in VB 5.0) is on the CD included with the kit.

    The parts for this project are included in the Sensor Kit. The Sensor Kit also includes the parts needed to do the temperature sensor project and the data collection project. The kit includes:

    1 - AT89C2051-24PC Microcontroller (unprogrammed)
    1 - 11.0592 MHz Crystal
    2 - 33pF Capacitors
    1 - 150pF Capacitor
    1 - 10 uF Capacitor
    1 - 220 uF Capacitor
    1 - 8.2k Resistor
    5 - 240 Ohm Resistors
    5 - 510 Ohm Resistors
    5 - 1k Resistors
    5 - 2.2k Resistors
    5 - 5.1k Resistors
    5 - 10k Resistors
    5 - 15k Resistors
    1 - MAX232
    1 - ADC0804 (Analog to Digital Converter IC)
    5 - 1 uF capacitors
    1 - DB9 connector
    1 - CDS Photocell Light Sensor
    1 - DS1620 Temperature Sensor
    Jumper Wires



    check out this link for more details regarding hardware schematic and related documents,you can either request online for the cd also.

    the link is http://www.iguanalabs.com/tempture.htm -->

    hope this might help you out in your project.

    regards
    john



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  4. #4
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    8051 project using ds1620 using asm language

    You can also use...the good old LM35 temperature sensor. Just hook it up to the AD convertor....working fine for me.

    Good luck



  5. #5
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    ds1620 thermocouple

    Quote Originally Posted by MedTroics
    hi all
    i need helpfor temprature controller based on 8051 with type j
    sensor any one can help me for simple hardwre and support me
    at software
    thanks all
    MedTroics is more concerned to type J thermocouple rather than linear temperature transducer.

    I can tell you it wont find an elegant solution right on the shelf. If he really needs then he must listen at least to Ian's advices pointed out here :
    https://www.edaboard.com/ftopic142935.html

    In fact I don't understand why he must raised up another thread on same subject.

    In this article you can read :
    http://www.circuitcellar.com/library...31-Ciarcia.pdf
    Most designers avoid thermocouples because using them has usually involved considerable circuitry.
    The physical characteristics that produce temperature-sensitive outputs from thermocouples must also be compensated for elsewhere within the signal-conditioning circuitry.

    You can read more:
    http://www.omega.com/temperature/Z/pdf/z021-032.pdf
    http://www.circuitcellar.com/library...99/c1299cd.pdf

    If I were you I would switch to K type and use MAX6674.
    http://pdfserv.maxim-ic.com/en/ds/MAX6674.pdf

    Less headache.

    Otherwise you must take into account at least this reference table:
    http://www.omega.com/temperature/Z/pdf/z203.pdf

    Life is not as easy as we are expecting to be. That's it.



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  6. #6
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    light sensor based on 8051

    check on epanorama.net



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