A few question about this HC-SR501 pir

I bet some of you in here know lots about this PIR.

A.
The white plastic cap on the PIR is there to ensure a wide range detection, right? so If I take it off, will the detection area point straight ahead only? or will it even detect?

B.
I want the PIR to detect only in a restricted area of a few square meters 4 meters ahead, so I figured that I could restrict the detection area by positioning the PIR inside a tube which should work as "fences". Is that a good idea and should it be with or without the white plastic cap?

C.
Its a Pyroelectric infrared sensor right? (not to confuse with a Photoelectric right?), and this might be the dummest question, but where is the infra red light? do I need to provide that next to the HC-SR501?

D. I read instructions of how the PIR works, but I find the instruction I read hard to read/understand. Especially section 3.

Instructions for use:
1. the induction module powers on for about one minute after initialization, this module can output interval during 0-3 time, one minute after entering standby.
2. direct sunlight should be avoided as far as possible sources of interference, such as lighting close range module surface of the lens, so as not to introduce interference signals malfunction; using the environment as far as possible to avoid movement of the wind, the wind will cause interference to the sensor.
3. induction module used double Yuan probe, probe of window for rectangular, double Yuan (a, Yuan b Yuan) is located in more long direction of ends, dang human from left to right or from right to left walked Shi, infrared spectrum reaches double Yuan of time, and distance has poor value, poor value more large, induction more sensitive, dang human from positive to probe or from Shang to Xia or from Xia to above to walked Shi, double Yuan detection does not to infrared spectrum distance of changes, no poor value, therefore induction does not sensitive or does not work ; So when the sensor is installed should probe the dual directions and the directions of human activities up to parallel as far as possible, ensure human passes has dual induction by probes. In order to increase the sensing angle, this module uses the circle lenses, also make probes sensors on all sides, but in both directions up and down left and right side is still strong induction range, sensitivity, must still be installed as far as possible according to the above requirements.

D1) It says that it should have 1 minut to initialize, but what does the next text mean? (his module can output interval during 0-3 time, one minute after entering standby.) ?

D2) All I understand is that wind will make the bushes move and activate the sensor. And that sunlight also makes interference. But what does "such as lighting close range module surface of the lens," mean? close range modules? and "using the environment as far as possible" ? I know the translation of each word but I do not understand them in that sentence.

D3) okay, does anyone understand anything in this section? something about detection of side-movements is preferred rather than movements in depth. I understand that. But is that all?

Thank you for any input regarding this. Have a nice sunday.

 

hi C,
A.
The white plastic cap on the PIR is there to ensure a wide range detection, right? so If I take it off, will the detection area point straight ahead only? or will it even detect?

It is a type of Fresnel lens cover which means simply the pattern of the lens causes a slight change in the light [ IR body radiation] falling on the sensor, it need this effect in order to create a AC signal which can be amplified.

B.
I want the PIR to detect only in a restricted area of a few square meters 4 meters ahead, so I figured that I could restrict the detection area by positioning the PIR inside a tube which should work as "fences". Is that a good idea and should it be with or without the white plastic cap?

You can mask off the sides of the lens cover to give a narrower detection angle.

C.
Its a Pyroelectric infrared sensor right? (not to confuse with a Photoelectric right?), and this might be the dummest question, but where is the infra red light? do I need to provide that next to the HC-SR501?

PIR stands for Passive Infra Red radiation detector, body heat provides the signal.


E

 

Instructions for use:
1. the induction module powers on for about one minute after initialization, this module can output interval during 0-3 time, one minute after entering standby.
2. direct sunlight should be avoided as far as possible sources of interference, such as lighting close range module surface of the lens, so as not to introduce interference signals malfunction; using the environment as far as possible to avoid movement of the wind, the wind will cause interference to the sensor.
3. induction module used double Yuan probe, probe of window for rectangular, double Yuan (a, Yuan b Yuan) is located in more long direction of ends, dang human from left to right or from right to left walked Shi, infrared spectrum reaches double Yuan of time, and distance has poor value, poor value more large, induction more sensitive, dang human from positive to probe or from Shang to Xia or from Xia to above to walked Shi, double Yuan detection does not to infrared spectrum distance of changes, no poor value, therefore induction does not sensitive or does not work ; So when the sensor is installed should probe the dual directions and the directions of human activities up to parallel as far as possible, ensure human passes has dual induction by probes. In order to increase the sensing angle, this module uses the circle lenses, also make probes sensors on all sides, but in both directions up and down left and right side is still strong induction range, sensitivity, must still be installed as far as possible according to the above requirements.

It means the warmed body object must be moving across the central axis of the sensor, left to right, up or down.

D1) It says that it should have 1 minut to initialize, but what does the next text mean? (his module can output interval during 0-3 time, one minute after entering standby.) ?

It means it takes about 3 mins to stabilise after power ON

D2) All I understand is that wind will make the bushes move and activate the sensor. And that sunlight also makes interference. But what does "such as lighting close range module surface of the lens," mean? close range modules? and "using the environment as far as possible" ? I know the translation of each word but I do not understand them in that sentence.

It means any object that reflects sunlight or cause a shadow pattern on the light falling on the sensor will trigger it.


D3) okay, does anyone understand anything in this section? something about detection of side-movements is preferred rather than movements in depth. I understand that. But is that all?

Yes.