Speed control of ceiling fan using PWM technique

Automisation plays a vital role in humans everyday life and the role of automatic control has increased significantly. Automisation is a vast advanced technological area whose motive is to develop control strategies and upgrade the performance applied to a device. One of such device is the fan. The traditional system fans are available with manual speed control depending on the requirements speed is controlled. Usually, the traditional system fans run at high speed at high temperature and low at lower temperature. In this paper, to contro the speed of the fan a circuit comprising of microcontroller PIC16F877A, temperature sensor, ultrasonic sensor, optocoupler circuit, BLDC motor and few electronic components is used. Moreover an ultrasonic sensor is used for automatic detection of human body in the room depending on which the fan gets operated and LCD is used to display the temperature, no. of people in the room and the speed of the fan.