AUTOMATIC ROOM LIGHT CONTROL WITH BI DIRECTIONAL VISITOR COUNTER

MICRO-CONTROLLER BASED PROJECT The objective of this project is to make a controller based model to count number of persons visiting particular room and accordingly light up the room. Here we can use sensor and can know present number of persons. In today’s world, there is a continuous need for automatic appliances with the increase in standard of living, there is a sense of urgency for developing circuits that would ease the complexity of life. Also if at all one wants to know the number of people present in room so as not to have congestion. This circuit proves to be helpful. RECEIVER CIRCUIT

TRANSMISSION CIRCUIT

this circuit diagram shows how a 555 timer IC is configured to function as a basic monostable multivibrator. A monostable multivibrator is a timing circuit that changes state once triggered, but returns to its original state after a certain time delay. It got its name from the fact that only one of its output states is stable. It is also known as a ‘one-shot’. In this circuit, a negative pulse applied at pin 2 triggers an internal flip-flop that turns off pin 7′s discharge transistor, allowing C1 to charge up through R1. At the same time, the flip-flop brings the output (pin 3) level to ‘high’. When capacitor C1 as charged up to about 2/3 Vcc, the flip-flop is triggered once again, this time making the pin 3 output ‘low’ and turning on pin 7′s discharge transistor, which discharges C1 to ground. This circuit, in effect, produces a pulse at pin 3 whose width t is just the product of R1 and C1, i.e., t=R1C1. IR Transmission circuit is used to generate the modulated 36 kHz IR signal. The IC555 in the transmitter side is to generate 36 kHz square wave. Adjust the preset in the transmitter to get a 38 kHz signal at the o/p. around 1.4K we get a 38 kHz signal. Then you point it over the sensor and its o/p will go low when it senses the IR signal of 38 kHz.