ppt on temperture detector using atmega 16
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By using a digital thermometer LM35 year tempIntroduction
Digital thermometer is a good choice for beginners who only stepped into the world of microcontrollers, because it provides the opportunity to learn using sensors to measure real-world analog signals that there is in nature. This article describes such a project based on a PIC16F688 microcontroller and temperature sensor LM35. LM35 sensor that converts analog year ambient temperature to a proportional analog voltage. The output signal from the sensor is connected to one of the inputs of the ADC in a PIC16F688 microcontroller to obtain an equivalent temperature in digital format. the temperature is displayed in 16 x 2 character LCD display, in either° C or° F scale.
theory
LM35 series of temperature sensors produced by National Semiconductor Corporation and is designed to work over the -55° c to 150° c temperature range. Woven sensors do not require any external calibration and output voltage is proportional to the temperature coefficient for temperature up to 10 MV voltage transformation° with LM35 series sensors come in different packages. hermatic I used is a TO-46 package transistor in which the metal housing is connected with the negative pin (GND).
Measuring negative temperatures (below 0° C) requires a negative voltage source. However, this project does not use any negative voltage source, and hence Will use proven sensor for measurement of temperature above 0° C (up to 100° C).
The output voltage from the sensor into a digital signal 10 bit a/D CONVERTER using internal PIC16F688. Since the voltage to be measured ranges from 0 to 1.0 a/D CONVERTERS in (which corresponds to a maximum temperature of 100° C), the lower the ADC requires a reference voltage (Vdd supply voltage instead of = 5V) for A/D conversion in order to obtain higher accuracy reference voltage below concerning may be achieved by a diode, resistor network or just a simple diode. You can refer to a voltage 1 .2V output approximate year by connecting the two diodes and the voltage consistently through resistor
-See: http://embedded-labblog/?p=916#sthash.QhJ106hS.dpuf