This document describes an automatic room light intensity based window blinds control system that opens and adjusts the angle of window blinds based on outdoor sunlight intensity readings from a light dependent resistor sensor. The system uses a pic microcontroller to take readings from the sensor, determine the appropriate blinds opening angle, and activate a stepper motor driver to position the blinds accordingly. This aims to utilize natural sunlight for indoor lighting and reduce household electricity costs for lighting by an estimated 20-30%. The microcontroller firmware is developed in Embedded C for ease of development and debugging compared to assembly language.

1. AUTOMATIC ROOM LIGHT INTENSITY BASED WINDOW
BLINDS CONTROL SYSTEM
ABSTRACT
Typical mid-income households spend Rs300 to Rs500 per month on electricity – 800 to
1000 kilowatt-hours (kWh). Most households could save 20 - 30 % of this easily if we can
use efficient equipment and even more we can save if we can utilize the outside sun light for
lightening. In this project we have planned to develop an automatic Blinds control system in
accordance with outside sunlight to save the electricity. Whenever there is sunlight outside,
blinds are opened to utilize that light avoiding need of electric lights. Blinds angle of opening
is proportional to sunlight intensity.
To control the blinds we plan to use Stepper motor and intensity of sunlight is sensed using
Light Dependent Resistance interfaced to on chip ADC of microcontroller. It takes input from
sensor, decides the angle of opening for blinds and activates the stepper motor through motor
driver.
Keeping in mind the vast technical and document support and integrated on-chip peripherals
available, high source and sink currents pic microcontroller is chosen. Because of less
development time, easy debugging and easy understandability compared to assembly
language, Firmware (software for embedded system) is developed in Embedded C.

2. BLOCK DIAGRAM