Hi shreenath,
If u are new comer to the field of robotics the best project with which u can start with is a line follower. Line follower is a robot which traces a black line on a white back ground(White line on black background and other line colors are also possible with slight modification and through proper calibration).
The simplest of the line followers could trace only simple lines without any sharp turns. For building such a robot u require two sensor pairs(preferably ir led and ir photodiode) to detect the line and to orient the robot properly on it. Then u have a control circuit to control the robot motion depending on the sensor feedback, motors to move the robot through the line and a power supply for supplying the necessary power to the sensors, circuit and motors. You will get a better tutorial for building such a robot in the ppt below
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