PIR Motion Sensor PaPIRs Cautions for Use

a) small animals entering the detection area

b) When a heat source, for example sun light, incandescent lamp, car headlights etc, or strong light beam hit the sensor regardless whether the detection area is inside or outside.

c) Sudden temperature change inside or around the detection area caused by hot or cold wind from HVAC, or vapor from a humidifier, etc.

a) Glass, acrylic or similar materials standing between the target and the sensor may not allow a correct transmission of infrared rays.

b) Non-movement or quick movements of the heat source inside the detection area.

In case of a considerable difference in the ambient temperature and the human body temperature, the detection area may be larger than the configured detection area.

On rare occasions, an erroneous detection signal may be output due to the nature of pyroelectric element. When the application cannot tolerate erroneous detection signals, take countermeasures by introducing a pulse-count circuit, etc.

Panasonic's PIR Motion sensors state the detection distance in the specifications because they are usually provided with the lens (please refer to item 6) for lensless types. The PIR Motion sensor could detect variations in infrared rays however such variations are decided by following three factors.

• The temperature difference between the target and the surroundings: The larger the temperature difference, the easier it is to detect targets.
• Movement speed: If the target is moving at a slower or faster speed than specified in the tables, the detection ability may be lower.
• Target size: The human body is the standard. If the target is smaller or larger than specified in the table, the detection ability may be lower.

The detection distance explained in our data sheet is defined by the three factors mentioned above. Panasonic's standard for the temperature difference between the target and the surrounding is defined as 4°C. The larger the temperature difference, the longer the detection distance. If the temperature difference is 8°C, which is twice as much as standard, the detection distance will be approx. 1.4 times longer than the distance at 4 °C. For example, if targets at a distance of 5m can be detected at 4 °C, then the sensor can detect targets at a distance of 7m at 8°C. (This is based on the theory that the detection sensitivity will vary inversely with the square of the distance.)

The lensless type cannot detect any targets because it is not possible to focus infrared variations into the sensor chip. It is not possible to determine the detection distance and the field of view without a lens. Please provide your own lens based on your lens design concept.

Typically, the only material that can be passed by infrared rays is Polyethylene. (The lens material of Panasonic's PIR Motion sensors is "High density polyethylene, HDPE".) When you need to set a plate in front of the lens, please choose one made from the Polyethylene. Please note the thickness or color of the plate will affect the detection ability, e.g. it may make the detection distance shorter. Therefore, please confirm by testing the sensor with the plate under realistic conditions.