The document discusses sensors used in robotics. It describes common sensors like light dependent resistors (LDRs), light emitting diodes (LEDs), thermistors, and infrared (IR) photo diodes that are used to detect light, temperature, and proximity. It provides an example of how an optical sensor array and steering controller can be used to make a line following robot that tracks a line on a surface using sensor feedback. The line following algorithm assigns weights to the sensor readings and uses the weighted sum to determine the line position and control the robot's steering.

1. TECHNOLOGY ROBOTICS SOCIETY Indian Institute of Technology, Kharagpur

2. A TUTORIAL ON ROBOTICS Sensors

9. Sensor Interfacing Light Sensing Module using LED-LDR combination

10. Sensor Interfacing Bump Detector Module

12. Block Layout of Line Follower Optical Sensor Array Steering Controller Left Motor Right Motor

13. Line Following Algorithm Step1: All the sensors are assigned some weight such as Sensor 1 = a1 = 3 Sensor 2 = a2 = 2 Sensor 3 = a3 = 1 Sensor 4 = a4 = -1 Sensor 5 = a5 = -2 Sensor 6 = a6 = -3 Step2: Let b1 – b6 denote the state of each sensor. 0 for white line and 1 for black line Step3: Line Position = Σ aibi Step4: Vcm is fixed, predetermined ω cm is proportional to Line position Step5: Vl = Vcm + ( ω cm / a) Vr = Vcm – ( ω cm / a) a : Separation between left/right wheels