PIR sensor test

Now I have completed the basic tests of the PIR sensor.

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*** Old blog notes ***

Now I am doing more testing on the PIR sensor.  After a couple of trials and errors, I discovered that the 120 degrees effective angle seems not meaning the horizontal plane angle as look at the top, but rather a cone like angle with origin at the centre of the plane where the spherical thing stands.

I also found that using a small or big bowl, or even the metallic rice cooker pot (which says that it transmits infra red rays when heated up) is not a handy way to shield human infra ray.  The most effective way is not to shield the IR, but say motionless for a couple of seconds.

...

So I went read the manual to see how to adjust sensitivity etc.  Then I found that I made a careless mistake.  Actually the no IR signal output is 0V, and IR signal output is 3V.  I also googled the sensor IC BIS0001 datasheet to see if the output can drive a LED.  The datasheet does not specify the output current rating but the application suggestion uses a NPN transistor to drive a relay.  So I think it is not a good idea to use the BIS0001 to drive an indicator LED.

The datasheet also suggests to cover the sensor with something to block the IR signal to check if the thing is working.  So I used my rice bowl to do the trick.  I covered the sensor but did not see any thing happening.  But then after a couple of seconds, the digital meter reads 0.1V.  So my RMB10 cheap toy is working!


So that is the end of my PIR (Passive Infra Red) sensor experiment and lesson.  The BIS0001 datasheet explains the very complicated theory of how it works.  But I am too lazy to read the details.


And I call it a day.

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So I started testing the PIR sensor.  I applied 5V to the cheap PIR (RMB10) and used my cheap meter (RMB30) to check the output.  I found the output around 3V3, but disappointedly I could not change it to about 0V.  I thought if I move my body, arms and so on, the output would drop to 0V.  But that did not happen.

I guess I need to read the manual to see if I could adjust the sensitivity or something.

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