Wanted to start a list of known sensors that might be useful in an HCI application… here is what I have so far please feel free to add.

• Accelerometer
• Touch sensor
• Active pixel sensor
• Air flow meter
• Alarm sensor
• Bhangmeter
• Biochip
• Biosensor
• Breathalyzer
• Capacitance probe
• Carbon paste electrode
• Carbon monoxide detector
• Catadioptric sensor
• Catalytic bead sensor
• Cationic sensor
• Charge-coupled device
• Chemical field-effect transistor
• CO2 sensor
• Colorimeter
• Crank sensor
• Curb feeler
• Current sensor
• Defect detector
• Displacement receiver
• Electrolyte–insulator–semiconductor sensor
• Electromechanical film
• Electronic nose
• Electro-optical sensor
• Ethanol sensor
• Fish counter
• Flow sensor
• Gas detector
• Geophone
• Hall effect sensor
• Hall probe
• Heat flux sensor
• Hydrogen microsensor
• Hydrophones
• Hygrometer
• Image sensor
• Inclinometer
• Inductive sensor
• Inertial Reference Unit
• Infrared point sensor
• Infrared thermometer
• Intelligent sensor
• Lab-on-a-chip
• Lace sensor a guitar pickup
• Laser distance measurement sensor
• Level sensor
• Light-addressable potentiometric sensor
• Linear encoder
• Linear variable differential transformer
• Liquid capacitive inclinometers
• Machine vision
• Magnetic anomaly detector
• Magnetic level gauge
• Magnetometer
• MAP sensor
• Mass flow sensor
• Metal detector
• Microbolometer
• Microphone
• Microwave chemistry sensor
• Microwave radiometer
• Molecular sensor
• Motion detector
• Net radiometer
• Nondispersive infrared sensor
• NOx sensor
• Optode
• Oxygen sensor
• Parktronic
• Parking sensors
• Passive infrared sensor
• Pellistor
• Photodiode
• Photoelectric sensor
• Photoionization detector
• Photomultiplier
• Photoresistor
• Photoswitch
• Phototransistor
• Phototube
• Piezoelectric accelerometer
• Piezoelectric sensor
• Potentiometer
• Potentiometric sensor
• Position sensor
• Pressure sensor
• Proximity sensor
• Pyranometer
• Pyrgeometer
• Quantum sensor
• Rain sensor
• Rain gauge
• Reed switch
• Resistance thermometer
• Rotary encoder
• Scintillation counter
• Seismometers
• Sensor array
• Sensor node
• Shack-Hartmann
• Smoke detector
• Sniffer coil (detects electromagnetic fields)
• Soft sensor
• Speed sensor
• Staring array
• Strain gauge
• Stud finder
• Sulphur dioxide sensors
• Thermal sensor
• Thermistor
• Thermocouple
• Throttle position sensor
• Tilt switch
• Torque sensor
• Touch pad
• Transducer
• Touch screen
• Triangulation sensor
• Ultrasonic sensor
• Variable reluctance sensor
• Variometer
• Video sensor
• Velocity sensor
• Vibrating structure gyroscope
• Viscosity sensor
• Wavefront sensor
• Wheel speed sensor
• Wired glove
• Yaw rate sensor

RFID tags look like the most promising at this stage. Although one does need to be careful about reader distance so that tags aren’t read prematurely.

flex sensors (http://devices.sapp.org/component/flex/)

e field sensors (Freescale Semiconductor MC33794D)

Q-touch capacitance sensors (http://www.qprox.com/technologies/qtouch.html)

swiss ranger (http://www.acroname.com/robotics/parts/R317-SR4000-CW.html)

silicon pressure sensor (http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=0112699036)

PIR sensor (http://en.wikipedia.org/wiki/Passive_infrared_sensor)

something that might interest....(http://circuit.ucsd.edu/~curts/papers/SPMag02.pdf)

softpots, posted elsewhere also - http://spectrasymbol.com/typo3/site/en/softpotsplash/softpot.html