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Need help in source code please send the source code to anuakhi125[at]gmail.com
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A microcontroller-based temperature display that shows the temperature in the range of -55 ° C to 125 ° C. In addition to the AT89C52 micro controller, it uses a temperature sensor chip and an annLCD module. The indicator outputs the calibrated data in digital form. The program for the microcontroller is written in C and not Assembly language. Since program C has a well-defined syntax, it far exceeds the merits of the assembly language program. Displays the block diagram of the temperature display using the AT89C52 microcontroller. The circuit supply is regulated by IC 7805 and supplied to different parts of the unit. DS1621 is the temperature sensor chip. The microcontroller (MCU) unit reads the temperature of the sensor. The temperature data is compared to certain user-defined temperature values and processed within the MCU according to the program and then sent to the LCD for display. Displays the temperature indicator circuit using the AT89C52 microcontroller. The work of each section of the circuit is covered in the following paragraphs
Power supply: The power supply consists of a transformer reducing (primary 230V AC to 0-9V, secondary 250mA), bridge rectifier and voltage regulator. The output of the transformer is fed to bridge rectifier diodes D1 to D4 (each of 1N4007). The ripple of the output bridge rectifier is filtered by the capacitor C1 and fed to the regulator IC 7805. The regulated output is given to the temperature sensor, the microcontroller unit and the LCD module, respectively. When switch S1 is closed, LED1 illuminates to indicate the presence of power in the system.
Temperature sensor: DS1621 chip temperature sensor (IC3) is an 8-pin DIP IC. Its details are shown in Fig. 3 and the internal block diagram of Fig. 4. The chip can measure temperatures from -55 ° C to + 125 ° C in increments of 0.5 ° C, which are read as values Of 9 bits. It can run off 2.7V to 5.5V. The data is read / written via a 2-wire serial interface. The pins 1 and 2 of the temperature IC are connected to the pins 11 and 10 of the microcontroller, respectively. The temperature below the TL temperature defined by the user. User-defined temperature settings are stored in non-volatile memory. Temperature settings and temperature readings are communicated to the DS1621 IC via a 2-wire serial cable. The most significant bit (MSB) of the data is transmitted first and the last significant bit (LSB) is transmitted last.
Circuit diagram: