### device | sensor:

Digital sensor
* gauge the amount of light coming from different types of terrain on the ground.
* measure when and how long an event occurred.

Electromagnetic sensor
* detect target emitted electromagnetic radiation.
* determine the size and weight of the coins.

Electronic sensor
* adjust for all light changes
  - power to the wheels that have the best grip
* control the pressure and therefore the degree of slip and torque transfer.
* measure surface water deposition by a change in sensor resistance or capacitance.

Infrared sensor
* allow continuous monitoring of animal location.
* detect body heat and movement
  - changes in heat
  - heat from missile plumes
  - the comparative heat of objects
* discriminate between intruders and pets or falling leaves.
* pick up data both day and night.
* respond to the motion of a heat source, such as a person, within a space.

Light sensor
* deactivates the sounds when room is dark.
* keep brightness comfortable day or night.
* range from simple CdS cells to complex video cameras.

Mechanical sensor
* Some mechanical sensors drive mechanisms.
* measure a change in sensor length, size or weight caused by moisture deposition.

Metal detector
* All metal detectors have an audible note produced by the mixing of two oscillators.
* are as good as X-rays
  - located in jails
  - very sensitive machines that are many times misunderstood
* can also find old tools and other objects of yesteryear, commonly called relics.
* do create a false sense of security about keeping out unwanted objects.
* use various technologies involving magnetic fields to detect the presence of metal.

### device | sensor:

Motion sensor
* Some motion sensors have beams
  - measure height.
  * It is used for studying motions. It is connected to a data-logger. The data-logger is connected to a computer. The computer runs a data-logging program. The computer is connected to power, and a security system. Motion sensors have many uses including security
* are a vital component of comprehensive security systems for businesses and homes
  - useful for safeguarding the interior of the business and for catching intruders
* control lighting, depending on the presence of a person in the area.
* detect movement.
* protect property.

Occupancy sensor
* Most occupancy sensors operate by sensing heat or motion.
* detect the presence or absence of people and turn lights on and off accordingly.

Optical sensor
* are basically telescopes, gathering light reflected off an object in space.
* designed for FFVs measure the differences in the fuel mixture index of refraction.
* react to ultraviolet radiation from a spark or flame.

Passive sensor
* are dependent on the characteristics of the independent energy source.
* emit no energy of their own.

Photocell
* Turn on lights automatically from dusk to dawn with photocells.
* are devices that convert light into electrical energy.
* contain stacks of light-sensitive pigments.
* control light operation depending on surrounding light levels.
* detect marks on the disk.
* drift with age and temperature.
* respond to natural light levels.
* turn lights off during daylight hours
  - on and off in response to natural light levels

Photoelectric sensor
* is effective in detecting slow, smoldering fires.
* monitor the passage of product into, through and out of the system.
* sound when the smoke is dense enough to deflect a beam of light.

Pressure sensor
* Most pressure sensors utilize a rigid diaphragm as the primary sensing element.
* can also indicate machine health , like the oil sensor on an automotive engine.
* used in the consumer market have specialized functions.

Proximity sensor
* are place on objects of interest.
* detect the presence of an object without physical contact
  - presence, absence, distance, and position of an object or person