To compare the Lighting of infrared LED and microwave radar
Lighting of infrared LED Microwave radar
Induction way Body infrared Microwave radar
Induction range Radius as 6~8meters Radius as 10~14meters
Temperature affect High Temperature detection NO
sensitivity will decreased
Sensitivity degree High Most High
Power 0.1W 0.3W
Firstly: what is infrared LED lamp
Infrared induction, an accurate express is passive infrared sensor,
is detection about 10uM infrared to work by the infrared probe passive detection。 The car (or people) emission around 10uM infrared to infrared inductive source by Finel filter after enhancement, infrared sensors commonly used source of pyroelectric element,
the element will be lose charge balance when receiving temperature is changes the element to the infrared radiation temperature on the receiving changes will lose charge balance, outward release charge, following circuit can generate alarm signal detected after treatment. Phenanthrene Er filter mud according to performance requirements are different, with different focal length (distance induction)
Secondly: the factors of influencing infrared LED lamp induction distance:
*the market most of the infrared induction LED, adopted two sensitive element design, induction angle is 120 degrees, the window is small, phenanthrene Er filter mud focal length (distance induction) small, therefore the induction distance near. The new technology adopts four sensitive element design, induction angle is 150 degrees, with large windows, so the induction distance.*infrared pyroelectric sensor on the vehicle (body) sensitive degree
has a very bag relationship with motion direction of people。Infrared pyroelectric sensor is not sensitive to the radial movement reaction, and for the transverse direction (i.e., perpendicular direction) movement were the most sensitive; therefore the infrared induction LED, when installing to try and lane parallel, lamp mounting angle adjustments, as far as possible need to probe direction oriented induction area, so the induction distance. Note: the parameters in the 8 meters to do the tangential
Thirdly: The working principle of microwave radar sensor:Using the Doppler principle to make the electromagnetic wave。any wave with reflection properties, when a certain frequency of the wave barrier encountered, there will be a part of the wave is reflected back, if the barrier is stationary, the reflected wave the wavelength is constant, if the barrier is an active object to the direction of movement away from the source, the wavelength of the reflected wave is more shorter than the wavelength of the wave source, if
the barrier is to the direction of movement away from the
wave source, the wavelength of the reflected wave than the wavelength of the long wave source, wavelength change, it means that the frequency change. Microwave induced by changes in the reflected wave is precisely aware of moving objects approaching or away, and output an electrical signal base this change of Microwave。 direction in forward direction of movement.Infrared lamp hanging height or less than 2.5 meters, the induction zone is 8 meters in diameter (radius as 4meters) around the ellipse.
*The lens or induction window is not covered with ash, dust can affect the sensitivity and sensing range, careful lens removal and installation, can static cloth to wipe The lens;
*when the environment temperature close to the temperature of the human body, the detection sensitivity will decreased significantly, in sometimes has resulting in short-term failure, commonly known as the temperature drift, the induction lamp adapted temperature drift suppression design, can overcome this problem
Fourthly: Characteristics of microwave radar sensor:
* The probe to detect the activity of a person or object as the goal,
as long as there have move people or object in the control range of microwave inside, can sensitively induction trigger.
* sensor through transmitting and received by the antenna signal board is the self to complete the exploration activities, microwave signal radiated from the antenna can penetrate nonmetallic materials, such as curtains, thin wall.
* sensor based on different performance requirements, can adjustable to different sensing range and sensing range.