PIC16F877A microcontroller is used to control the whole system. It is designed using flash technology. So the PIC can read/write program for more than 100,000 times. The PIC can store up to 8Kbytes program. A program is downloaded into PIC through PIC programmer. This program will be used to operate the system.The PIC can operate using 4.5V to 6.0V DC voltage. In the project is operating at 5.0V (by using 7805). It is DIP layout (dual in line package) and suitable for student project. It has 40 pins but only 33 I/O pins can be set as digital input or digital output. The digital output of the PIC is 5V (for signal 1) and 0V (for signal 0) these signals will be directly connected to actuators for control purpose. When the PIC pin is set as digital input. It will detect input voltage 5V as signal 1 and 0V as signal 0. Any voltage less than 0V or more than 5V will damage PIC.
A normal LED use 5V and 5mA to operate. And through LED the current status of the system can be known. A 1KR resistor is connected series with the LED to limit the current pass through LED is 5mA. This is calculated using V=IR. Where V=5VDC, R=1KR. The LED will light on when the power is go through the circuit to alert user.
The variable resistor is to control the dimmer of the light and the speed of the fan. And as for the push button, it is for turn on or off the relay at the receiver module. When the remote is complete, only the push button will display on top of the remote.
No comments:
Post a Comment