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underwhelmd
Posts: 94
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Location: East Coast, Canada

PIR motion sensor alternatives?

Sat Jul 29, 2017 7:07 pm

I am looking for an alternative to a PIR motion sensor to mount in a box with the pi and it's camera. The box is outside and will see snow on it during the winter but is sheltered from rain. I liked the PIR sensor because I could make a round hole in the box cover and seal it but it ~probably~ won't work because the area is bathed in IR light from an illuminator. From what I'm reading, the two don't work together very well...

Can you recommend another type of motion sensor that is weatherproof-ish, plays nice with a Pi and won't be bothered by an IR illuminator? The project is: sensor sees movement, if at night then Pi does something.

Thanks in advance.

pcmanbob
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Location: Mansfield UK

Re: PIR motion sensor alternatives?

Sat Jul 29, 2017 8:32 pm

Hi.

I think you will find your PIR will work just fine even with IR illumination directed at it.

I have a PIR on one of my pi projects, I also have a IR LED lamp ring from a cctv camera, have the IR light source pointing at the PIR and it does not detect it even if the IR lamp is just inches away from the PIR.
Unless the IR source is moving which fixed IR illumination should not do.

If you have the kit before you go any further I would run some tests just to see if your PIR will work ok

Edit.

Not sure the PIR was seeing the IR source moving moving the PIR with out the IR source still sees movement.
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underwhelmd
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Location: East Coast, Canada

Re: PIR motion sensor alternatives?

Sat Jul 29, 2017 10:16 pm

pcmanbob wrote:
Sat Jul 29, 2017 8:32 pm

I think you will find your PIR will work just fine even with IR illumination directed at it.


Thank you for your reply.

The area the PIR sensor would be pointed toward is lit with IR, but the light isn't pointed right at the PIR. I will give it a test to see if it works even so. I don't need to drill holes in the box to wire it up and see...

I appreciate your advice.

pcmanbob
Posts: 7264
Joined: Fri May 31, 2013 9:28 pm
Location: Mansfield UK

Re: PIR motion sensor alternatives?

Sat Jul 29, 2017 10:28 pm

underwhelmd wrote:
Sat Jul 29, 2017 10:16 pm
pcmanbob wrote:
Sat Jul 29, 2017 8:32 pm

I think you will find your PIR will work just fine even with IR illumination directed at it.


Thank you for your reply.

The area the PIR sensor would be pointed toward is lit with IR, but the light isn't pointed right at the PIR. I will give it a test to see if it works even so. I don't need to drill holes in the box to wire it up and see...

I appreciate your advice.
I think you should be ok , while sat here realised I have the same setup but not with a PI, have outside lights which are PIR controlled and CCTV cameras each with its own IR LED array and my lights don't switch on even when the IR LEDs switch on just after dusk and only trigger when movement is detected.
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OutoftheBOTS
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Re: PIR motion sensor alternatives?

Tue Aug 01, 2017 10:32 am

most of these PIR movement sensors work by taking images and compare the differences between each image and any difference is motion. The good thing about these typoe of sensors is they see infrared light not visible light meaning they are seeing body heat, so if trees blow in the wind it won't set of the motion sensor but if somthing warm like a body of a person or animal moves then it is seen :)

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Ferdinand
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Location: Leiderdorp, NL

Re: PIR motion sensor alternatives?

Tue Aug 01, 2017 1:43 pm

Perhaps a radar sensor like rcwl 0516 could replace a pir sensor. You don't have to drill a hole for these type of sensors. See aliexpress.com or youtube for more information. If I'm right the output is 3.3 V.
Success with your project!
Ferdinand

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underwhelmd
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Location: East Coast, Canada

Re: PIR motion sensor alternatives?

Wed Aug 02, 2017 4:22 pm

Thanks guys. I have found the PIR sensor does work with the area lit with IR light.

There is a however: however, it will detect sooner if no IR light. I'm ok with how it works for me in this situation but it's something to consider.

wwwenrico
Posts: 1
Joined: Thu Jun 13, 2019 1:40 pm

Re: PIR motion sensor alternatives?

Thu Jun 13, 2019 1:49 pm

pcmanbob wrote:
Sat Jul 29, 2017 8:32 pm
Hi.

I think you will find your PIR will work just fine even with IR illumination directed at it.

I have a PIR on one of my pi projects, I also have a IR LED lamp ring from a cctv camera, have the IR light source pointing at the PIR and it does not detect it even if the IR lamp is just inches away from the PIR.
Unless the IR source is moving which fixed IR illumination should not do.
Hi,

IIR leds emit radiation at 850 nano meters.

PIR sensors are sensitive to radiation at 12000 nano meters.

It's more than obvious that PIR sensors are not affected by IR led sources.

Yet, all PIR sensors have a small Silicon optical filter that filters out all the radiation outside the 1000-14000 nano meters range.



Ciao,
Enrico Migliore

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