This category includes sensors with analog or digital rangings sensors where the output is proportional to sensed distance.

• Sharp GP2Y3A001K0F (4-30cm range, analog out)
• Agilent HSDL-9100 IR Ranging Sensor (Infrared, needs external ambient light filtering)
• Tak says to put a 20uF electrolytic cap across the power/ground of each sensors. Optionally put a ceramic cap in parallel.

This category includes sensors that have a binary output only. Typically a reflective surface at or within some preset distance will trigger the sensor output.

This category includes ground imaging sensors and CCD-based imaging systems.

• Agilent ADNS-6031/2 Laser Optical Tracking IC (800cpi, low power)
• Agilent ADNS-6011/2 Laser Optical Tracking IC (2000cpi, faster speed tracking, higher power)

This category includes tachometer and frequency-based magnetic/optical encoding/decoding sensors, hardware and related ICs?

• Agilent HCTL-1100 (Full motion interface IC, PWM generation, velocity register)
• Agilent HCTL-2032-SC Quadrature Decoder IC (Dual-axis, 32-bit registers, 8-bit parallel interface)
• Agilent AEDR-8xxx Reflective Optical Encoder (Surface-mount IC for use with reflective codewheel)
• ALPS Rotary Thru-Shaft Potentiometers (Hard to get)

• Agilent HDJD-S722-QR999 Color Sensor (Senses individual R, G, B levels, small SMT package)