Should we use ultrasonic sensors for wall following or IR,bump sensors?
Each method has advantages and drawbacks. Ultrasonic sensors are somewhat directional. If the robot is running parallel to a wall, and the sensor is aimed at the wall, it can not see a wall at 90 degrees to the robot. So the robot will tun into the wall.
If the sensor is parallel to the direction of travel, how do you follow the wall?
IR sensors are affected, to various degrees, by ambient light. Fluorescent lighting, incandescent lighting, and natural lighting can all affect the IR sensor.
Bump switches are the most accurate, because distance is known when the switch is activated.
So ,i came up with few ideas viz. finding no. of revolutions madeby it ,setting constant speed and using timer,using distance sensors(IR) etc.
None of which are terribly accurate. Timing does not account for acceleration and deceleration, nor does it account for slippage (when one rotation of the tire does not result in an equal amount of forward motion). IR sensors are affected by lighting and the degree (and angle) of reflectivity of whatever reflects the IR signal.
Under what conditions is this robot to be used? What will the resulting area information be used for?
Putting the robot in a room and having it guesstimate area so you know how much carpet or paint to but is one thing. If you need to know the area more exactly, that is another.