[is] equipment which detects, and may indicate, and/or record objects and activities by means of energy or particles emitted, reflected, or modified by objects. Note. The energy may be nuclear, electromagnetic, including the visible and invisible portions of the spectrum, chemical, biological, thermal or mechanical, including sound, blast and earth vibration.
[is a] device that produces a voltage or current output that is representative of some physical property being measured (e.g., speed, temperature, flow).
Sensors are a type of electronic device that must produce the miniscule amount of power required to convey information at a usable error rate. Sound, light, atmospheric conditions, vibrations, and other environmental signals are all fair game for sensor designers.
Basic properties, assumptions, recommendations, and general statements about sensor include:
9. Sensors may have an owner(s) who will have control of the data their sensors collect, who is allowed to access it, and when.
10. Sensors will have pedigree — geographic locations of origin and manufacturers. Pedigree may be unknown, and suspect.
11. Sensors may be cheap, disposable, and susceptible to wear-out over time.
12. There may be differentials in sensor security, safety, and reliability, e.g., between consumer grade, military grade, industrial grade, etc.
13. Sensors may return no data, totally flawed data, partially flawed data, or correct and acceptable data. Sensors may fail completely or intermittently. They may lose sensitivity or calibration.
14. Sensors are expected to return data in certain ranges, e.g., [1 ... 100]. When ranges are violated, rules may be needed on whether to turn control over to a human or machine when ignoring out-of-bounds data is inappropriate.
15. Sensors may be disposable or serviceable in terms of calibration, sensitivity or other forms of refresh. Complex and expensive sensors may be repaired instead of replaced.