HC-SR501 PIR without the dome

Hi. I'm going to start a project with an ESP32-CAM and a motion sensor. The thing is that there is someone in the neighbourhood that allows his/her dog piss on my door almost every single day, and I want to know who that is (we don't have surveilance cameras here), so I thought of installing one small, inadverted device in the border of the door so when the dog does his things, I snap a picture and I can then know who that is.
The thing is that I believe that the dome in the PIR sensors widens the sensor area of effect, and I only want it to trigger when there's something/someone actually close to the door. Yes, for sure it will snap a few pictures of ourselves when we get in and out, that's ok, but I don't want it to do it every single time someone passes by.
My question is: can I remove the white dome of the sensor? will that make it more focused so it only triggers the picture when something is in front of it?

Hi @Assamita
You can remove the dome, I don't know if it will be more targeted.
But how about making a humidity sensor to trigger the camera.
Urine contains a lot of salt and makes it easy to get large variations in values between when it is dry and when it is "urinated"? :grin: :grin: :grin:

RV minieirin

Thank you @ruilviana , but it's a small dog and doesn't always pee in the same spot. It would need to be a door wide sensor (happy to accept suggestions if that's actually feasible)

The "dome" is a special Fresnel lens. Without it the sensor cannot respond as both sides always see the same IR.

Just like a camera without a lens. :grin:

If you wish to narrow the view, you mask it.

The "dome" contains lenses that focus a small image on the actual sensor. When the target is moving, the lenses create a varying signal on the sensor and that varying signal indicates motion. Without the lenses, there is NO motion sensing!!!!

Understood, thank you.
And the sensitivity pot is to adjust the distance, correct? or the size of the "object"?

The sensor is sensitive to the heat, IR, from the object, so distance, size and heat radiation are all involved in "sensitive". The movement is what is being detected and reported.

Not really a suggestion, just a fun thought.

If you have a metal door, get a cheap TENs unit and connect one lead to the door and another lead on the porch with maybe a piece of aluminum screen.

Peeing will stop after one night.

To see what they are referring to, take off the dome and look through the lens. You will see as you pan the area stationary lights kinda blink on and off.
You can also use this method to "see" the results of masking.

I would try a paper towel core cut short and over the whole sensor to limit the response field.

I caught the neighbor I was annoyed by, can’t blame the dog…

setting up my action camera on time lapse

if I see new damages scrub through until poop magically pops into the scene

single step for beautiful still shots

It didn’t take long. Also caught a buncha other interesting things going on I never knew about!

Guy still claimed it wernt him. :frowning:


He's correct, it was his dog.

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No jokes, that was actually one of my next steps. I was going to expose him and if it kept happening, I thought of doing that, because the door is indeed metal.

Too bad you couldn't get him and not the poor dog.

No, its essential to function, its a series of fragmented prisms that mean movement is more likely to trigger the device. It translates movement of a point source of heat into fluctuations in brightness at the sensor die.

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