RIR - REFLECTIVE INFRARED SENSOR

RIR Reflective Infrared presence/proximity/motion detector with self programming detection range.

 

Unlike a Pyroelectric Infrared sensor (PIR) that is used in many motion detectors, the Reflective Infrared sensor (RIR) does not detect long wavelength infrared radiation emitted by a human or animal body. Instead, a device using an RIR sensor emits its own short wavelength infrared beam and the RIR detects the infrared that is reflected back to it from any human or non-human object within its automatically programmable detection zone. It can continuously detect the presence of both a moving and stationary object.

 

Short wavelength infrared used by the RIR will pass through most materials that are transparent to visible light. It reflects from both light and dark surfaces but reflection is stronger from light and smooth surfaces. Dark surfaces and textured surfaces that scatter light will result in less reflected light which the sensor within the RIR circuit will interpret as reflections from a more distant object. A reflective infrared system will therefore not produce an accurate measure of distance from the sensor to a detected object.

 

However, the purpose of the RIR is not to measure distance but to detect a stationary object, to detect motion toward and away from the sensor and to automatically control its detection distance with some variations as described above, none of which a pyroelectric infrared sensor can do. Table 1 shows a comparison between a pyroelectric and reflective infrared sensor system.

 

 

CHARACTERISTICS	Pyroelectric Infrared Sensor (PIR)	Reflective Infrared Sensor (RIR)
Sensor type	Passive	Active
Infrared wavelength	5 to 15 micrometers	940 nanometers
Detects IR from animal body	Yes- senses IR emission	No- needs LED IR source
IR will pass through glass, plastics	No	Yes
Detects metal objects	No- sometimes but not reliable	Yes- detects reflection
Very long detection range	Yes- More than 100 feet	No- Up to 20 feet
Can detect stationary object	No- Only moving	Yes- Stationary and moving
Detects movement side to side	Yes	Yes
Detects movement toward and away	No	Yes
Wide field of view	Yes- Depends on lens used	No- only narrow
Controllable detection distance	No- Background sensitive	Yes- Automatic programming
False activation by rain, snow	No	Yes
External lens required	Yes- Needs a Fresnel lens	No- Lens built into sensor
Can be powered by small battery	Yes- About 50 microamps	No- About 200 milliamps

 

Table 1

 

In one configuration, when power is applied the RIR will look at all objects within its field of view and will program its self to consider them as normal occupants of its detection zone. However, when a new object enters its zone it will immediately recognize that object as an intruder and will respond by turning its output on. The output will remain on until the intruder leaves the detection zone.

  

The RIR is especially useful to detect a stationary person or object. A typical application is to activate illumination of a picture or display in a gallery when a person approaches the display and then stands still in front of it. The RIR can easily be programmed to activate when a person is within a desired distance from the display by simply sequencing power or pressing a reset button while a person stands in front of the display. The RIR will measure and save the distance to the person as an activation zone and will thereafter activate the illumination whenever anyone enters a short distance inside that zone.

We will provide more information about this new device as it becomes available.

 

RIR/MOV01198.MPG