light sensitive trigger circuit

KKKL 2092 – Electrical and Electronics Laboratory I
Mini Project – (4) Light Sensitive Trigger

Problem Statement:
We usually meet with the problem where we want to switch on or off certain electronic devices when the light intensity is changes, such as the outside lighting on driveways, security system, counters, night lamp, etc. We need something that will controls the electronic devices smartly by varying the light intensity, thus a light-sensitive trigger circuit is required which required a light-dependent source as the input of the circuit that will varies certain parameters in the circuit and thus the timer IC 555 will act as a switch to control the output ( electronic devices ).

Main Objectives :
To build a light-sensitive trigger circuit that can be implemented in real world applications.

Sub-objectives :
i) To learn the function of Timer IC 555 as a monostable multivibrator in switching the output to high stable state.
ii) To learn the function of each components in the circuit design in varying the result of the output of the circuit.
iii) To learn how to ease the circuit building by using circuit simulation software.
iv) To learn how the values of the resistor and capacitor connecting with the timer IC 555 can change the time period of the unstable state of output.