In the field of robotics there are many different types of sensor models used in practice. These models can be classified as follows:

Category	Examples
Tactile	Switches/bumpers, Optical barriers, Proximity
Haptic	Contact arrays, Force/torque, Resistive
Motor/axis	Brush encoders, Potentiometer, {Optical, Magnetic, Inductive, Capacity} encoder
Heading	Compass, Gyroscope, Inclinometer
Beacon based	GPS, Active optical, {RF, Ultrasound, Reflective} beacon
Ranging	{Capacitive, Magnetic} sensors, Camera, Sonar, Laser range,
Speed/motion	Doppler {radar, sound}, Camera, Accelerometer
Identification	Camera, Radio freq. identification, RFID, Laser ranging, Radar, Ultrasound, Sound