I’ve 2 low power consumption type of PaPIRs which is EKMB1108111 and EKMB1110111. (1 uA type). These sensors are digital type of output
I test by
- connecting the sensor to arduino uno to test the output if it be able to detect something which simple code. ref. How to interface Panasonic PIR Motion Sensor with Arduino
- Use multimeter measure the output pin of the sensor.
The problem is
- After I’ve tested these 2 products, I found those sensors detect even non-living object such as empty bottle, pillow, chair, etc. (only when it was moving. - no moving 0, moving 1)
- panasonic pir sensor have low power consumption type (1,2,3,6 uA) and 170 uA type, are there any impact to its sensitivity
In response to your questions:
- It should be understood that these sensors do not not detect “living objects” per-se; they detect light in the infrared spectrum. It can be thought of like watching the pattern of light on a wall that comes through a window at night; streetlights or moonlight cast a dim but persistent glow, but a vehicle with bright headlights passing by produces a noticeably moving bright pattern. Similarly, an opaque body passing between the outside light source and the window casts a noticeably moving shadow in the pattern of background light. What sensors of this type do, in some sense, is watch for movement in the pattern of (infrared) light that comes through its window (lens).
All objects emit light in the infrared region, in relation to their temperature. Any object (not just warm-blooded animals) that are at a different temperature than their background can potentially trigger them. Because objects very in terms of their optical characteristics in the infrared region, moving objects that are at the same temperature as the background can still trigger them, particularly in they are presented very close to the sensor.
- The sensitivity and detection pattern of these sensors is mostly a matter of the lens/optical system, but there are likely some differences of an electrical nature that lead to the different current consumption numbers. Panasonic does not seem to do a good job of showing the differences between these different devices, so a person is sort of stuck choosing potential candidates based on other factors, and looking at individual device datasheets to determine if the sensitivity patterns are suitable for a given application.
I directly connect output pin from pir sensor to arduino board. When motion can be detected, the output is high but it seem the signal from sensor still high for a few second, and then go back to low, is it normal?, how can I turn the output signal low immediately when there is no motion.
From reading the data sheet linked on the product page, it appears you can not change the delays. They are built into the system to lower the power requirements and reduce the amount of external debouncing required.
I’m not sure if I understand correctly, is it normal behavior of panasonic pir, when I move my hand pass the sensor, the signal go high when my hand first move into the sensor area, and then the signal go to low in a split second and then go to high again after I put my hand still in sensor area or I move through
but some time, the signal is only [1 - 0 - 0 - 0 …] but not [1 - 0 - 1 - 0 - 0 - 0 …]
There are a lot of specs in the data sheet that could be confounding your tests. I recommend you study the whole data sheet very carefully. I’ve never worked with this particular part, and don’t have one to test, so all I can do is point out some of the data sheet specs that jump out at me as potential gotcha’s.
Power up time (Twu), 25 to 210 seconds. (you need a long wait after power up before readings are guaranteed to work)
Movement speed, 1.0m/s (hard to judge hand movement speed, try slower and faster movements)