Microwave Detectors / Sensors

The Microwave Motion Detectors / Sensors emit microwave signals and measure the time taken for the signal to be reflected back to the Sensor, this is known as the echo time. The echo time is used to calculate the distances from all the stationary objects in the detection zone, to establish a baseline to work from. A person moving into the detection zone causes a disruption in the microwave beam, changing the echo time and triggering the lights.

PIR Motion Sensors

The PIR Motion Sensors detect heat. They do this by measuring the ambient temperature of the room using several detection beams. When a difference in temperature is detected by one of the beams, the sensor is activated, switching on the lights. When all the beams sense the same temperature again, the lights will switch off.

PIR MOTION SENSOR MICROWAVE MOTION SENSOR Sensitivity Under sensitive in higher background temperatures.Over sensitive in lower temperatures. Consistent detection over all temperatures. Coverage 90°-180°-360° 360° Detection Can be insensitive when walking directly towards the sensor. Can sense movement through thin walls. What is PIR Motion Sensor?

A passive infrared PIR Sensor is an electronic sensor that measures infrared light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications.

Technically, PIR Sensor is made of a pyroelectric sensor, which is able to detect different levels of infrared radiation. For example, Everything emits varied level radiation and the level of radiation will increase with the increase of the object’s temperature. Actually, the PIR Motion Detector / Sensor is separated by two parts since motion change is what we want, rather than IR level. The output will swing high or low if one half see different IR radiation than the other.

What does a PIR Sensor detect?

As we all know that PIR Sensors / Detectors can be also refer to PID, which is short for passive infrared detectors. As you have learned about the technical term in the first part, PIR Sensor / Detector can detect infrared radiation which is emitted by particles.

Generally, PIR Sensor / Detector can detect animal/human movement in a requirement range, which is determined by the spec of the specific sensor. The detector itself does not emit any energy but passively receives it, detects infrared radiation from the environment. Once there is infrared radiation from the human body/ particle with temperature, focusing on the optical system causes the pyroelectric device to generate a sudden electrical signal and an alarm is issued.

How does PIR Sensor work?

The passive infrared alarm does not radiate energy to space but relies on receiving infrared radiation from the human body to make an alarm. Any object with temperature is constantly radiating infrared rays to the outside world. The surface temperature of the human body is 36-27° C, and most of its radiant energy is concentrated in the wavelength range of 8-12 um.

Passive infrared alarms can be classified into infrared detectors (infrared probes) and alarm control sections. The most widely used infrared detector is a pyroelectric detector, which is used as a sensor for converting human infrared radiation into electricity. If the human infrared radiation is directly irradiated on the detector, it will, of course, cause a temperature change to output a signal, but in doing so, the detection distance will not be far. In order to lengthen the detection distance of the detector, an optical system must be added to collect the infrared radiation, usually using a plastic optical reflection system or a Fresnel lens made of plastic as a focusing system for infrared radiation.

In the detection area, the infrared radiation energy of the human body through the clothing is received by the lens of the detector and focused on the pyroelectric sensor. When the human body (intruder) moves in this surveillance mode, it enters a certain field of view in sequence and then walks out of the field of view. The pyroelectric sensor sees the moving human body for a while and then does not see it, so the human body The infrared radiation constantly changes the temperature of the pyroelectric material so that it outputs a corresponding signal, which is the alarm signal.

What is the difference between PIR Sensor and Motion sensor?

The Motion Sensor is a device that can detect the movement of people or objects. In most applications, these sensors are mainly used to detect human activities in a specific area.

As it is capable of converting the motion it senses into electrical signals, the sensor either emits stimuli and monitors any changes reflected back, or acquires signals from the moving object itself. Some Motion Sensors will alarm when people or other objects invade and break the normal state, while others will alarm when they return to normal state after the invasion. Security systems all over the world rely on Motion Sensors to trigger alarms and/or automatic lighting switches, which are usually placed in relatively easy access to buildings, such as windows and gates.

PIR is only one of the technical methods to detect motion, so we will say PIR Sensor is a subset of Motion Sensor. Because of PIR Sensor are small in size, cheap in price, low-power and very easy to understand, which makes in quite popular. A lot of merchant will add "motion" between PIR Sensor for the convenience of beginners.

Does PIR sensor work in daylight and night?

If you can understand the above introduction, I think you will know the answer to this question. Of course yes, they work fine in daylight as well as in night.