Block Diagram of Temperature Controller With Egg incubators AT89C2051. Broadly speaking, the working principles of equipment from the block diagram described above is as follows:
LM35 temperature sensor will change the temperature scale into a voltage proportional to the temperature detected by 10mV/oC value. Then the voltage converted from the temperature sensor dubah become part of the frequency by voltage to frequency converter RC4151 with output frequency is 1000 x Vin. In part this frequency converter output voltage to the Schmitt trigger is passed on before they read by the microcontroller, it aims to improve the output of the converter in a digital pulse level. Keypad consists of three buttons is the SET button / OK, UP and DOWN. Keypad functions to deliver value setting the temperature limit means egg hatching at the desired temperature.
At the time the system starts the microcontroller reads the voltage frequency conversion results are comparable with the temperature read by the sensor. Microcontroller then compares these data with the frequency setting data, because data has not been loaded settings via the keypad, the microcontroller mengidentifkasikannya by setting 0 ° C so that the heater is not turned karen data of temperature readings greater than the setting data. Data readings are always displayed in units of temperature with a resolution of 0.1 oC oC. when the data of temperature readings is smaller than the data heater setting is enabled. Section zero crossing detector serves to medeteksi crosses 0 volts PLN nets that are used to initiate triac to activate the heating element in the form of incandescent lamp.