Please send me the ckt & program of ' automation room light intensity based window blind control system'.

A servo motor uses servo mechanism, which is a closed loop mechanism that uses position feedback to control the precise angular position of the shaft. Stepper Motors, which is an open loop system can also be used for precise angular control. But Servo Motors are preferred in angular motion applications such as robotic arm. Moreover controlling of servo motors are very simple, easy and needs no extra hardware like stepper motor. Usually hobby circuit servo motors have three wires. Two of them are red and black which is used to give power to the motor and the third wire is used to provide control signal for angular position. It uses Pulse Width Modulated (PWM) waves as control signals. The angle of rotation is determined by the width of the pulse at the control pin. The servo motor used here is having angle of rotation from 0 to 180 degrees. We can control the exact angular position by varying the pulse between 1ms to 2ms. Before using this in your application, please refer the datasheet of your servo for angle and pulse width informations.