Design and Construction of Photo Sensor Based Automatic Switch

The aim of this project is to design and construct photo sensor based automatic switch. The switch operates by sensing a hand near the switch. The switching is without human intervention. Initiation is done by the user bringing the hand near the switch but not touching the switch to initiate the dispensing of liquid. The electronic components used for the design and construction are BP104, AN304, 10 KΩ resistors, 10 KΩ variable potentiometer, LM 741, IRF 3205 and LED. This seeks to prevent touching of control knobs to dispensed liquid. This switch uses 12V DC supply. It can be connected to 12V DC pump to dispense liquid such as oil, water and drinks. The switch was designed using photo sensors, general purpose operational amplifier, variable resistor and fast switching power MOSFETIRF3205. The output of this switch can be connected to a pump to dispensed liquid such as water, oil and drinks. The type of sensor used in this system is a photo sensor(an optical sensor). The sensitivity ofthe switch can be varied to suit indoor and outdoor application