PRESENTED BY:
N. RAMAKRISHNA REDDY
DINESH REDDY
G. SPURTHI REDDY
MANASA

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MICROCONTROLLER BASED MULTIPLE DEVICE CONTROL BASED ON INPUT FREQUENCY.
DESCRIPTION:
The 230v ac supply is down converted into 12v by ac transformer. The transformer output is rectified by bridge rectifier and converts into pulsating dc. This voltage is given to the filter. The filter removes the unwanted ripple components and output of filter is gives the constant dc 5v.
The dc 5v is given to the microcontroller and to the potentiometer. The output of potentiometer is given to ADC of microcontroller. The PIC16F872 microcontroller consists of 8 bit ADC therefore the total size is 2pwr 8=256 bits from this we can say the microcontroller PIC16F872 can control 256 devices.
It consists of relay circuit based on relay circuit the devices (LCD) can be made on and off. If the switch (relay) is opened the LCD (device1) is made on in order to make the device off the switch (relay) is pressed this makes input to LCD (device) is 0v i.e., off state.
Let us take four devices in order to make the four devices on and off the size of ADC that is 256 is divided into four parts. Therefore the output of ADC lies in between 0 to 63 the device one i.e., first LCD is in ON state. In order to make second LCD to ON state the output ADC varies between 64 to127 this makes the second device into ON state. In this way all the devices can be made on and off.
It consists of crystal oscillator and control button. Crystal oscillator used to generate the signals, these signals control the microcontroller. The control button is used to know the device on and off states.
CONCLUSION:
I have come to the conclusion that above project is very useful in both economical and practically as it can be used to control the multiple device with less equipment at low cost.
VITS-I, KARIMNAGAR.