LIGHT INTENSITY LEVEL CONTROL

The purpose of the project is to design a light level intensity control using Light
Dependent Resistor (LDR) sensor. The main task for the project is to develop a light
detector circuit for controlling the light intensity level ina confined environment. The
light intensity is measured by using the LDR sensor while the microcontroller is
added to the circuit in order to detect and response to the light intensity and control
the intensity level toa preset value. The effect ofdifferent amount of light allows the
controller to switch at the desired intensity levels automatically. The dimmer uses the
technique ofAC phase angle control, where the loads are turned on for a portion of
the total AC line sinewave period. The changes of variable resistor value, will affect
the starting firing angle. The methodology of this project includes literature survey,
planning work, design, experimental/simulation step, implementation and
documentation of development progress. Literature survey was done to find the
existing AC phase control circuit that used to control the brightness/dimmer of the
lamp (load). The design step includes developing a microcontroller programming for
the automatically operation for brightness/dimmer purpose, PCB circuit design and
prototype construction. The combination between microcontroller program and the
AC phase angel control circuit allows the brightness/dimming a lamp to be controlled
automatically depending on the lighting condition in a confined space. Therefore, the
electrical power consumption could be controlled and thus it will be cost effective.
Overall, this project has achieved its objective and functions according to
specification. The brightness of the lamp (25 Watt) varies from a minimum load
consumption (7.7 Watt) to a maximum load consumption (22.9 Watt) and therefore
can be controlled to suit the lighting conditions.