PIR sensor (or some other method) that can detect a person/movement within close proximity?

Hardware Hub
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I have a Raspberry Pi connected to a small panel in the living room that I use to display my security camera streams.

It is sort of unsightly, so I’m curious if there is a PIR sensor that can detect a person within somewhat close proximity to the panel.

I’d like to display a slider of images (or possibly just a static image) like a digital picture frame until a person walks within a certain proximity of the panel (several feet), at which point it will open the browser (with the camera streams).

I have a couple PIR sensors , but I wasn’t able to get any of them to only detect “motion” when the person walked close to the sensor. The sensors I tried would always get triggered when people moved anywhere in the room.

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PIR sensors are basically a bunch of Fresnel lenses and they detect motion when infrared light “moves” across the detector inside. You can try positioning it above (or even in front of) your target area and blocking portions of the lens so it can’t “see” outside that specific area. Play with positioning and lens blocking.

Check out how different type lenses work and go from there:

Alternatively, and depending on your light source in the room, it may be as simple as using two (or more) photo resistors. Position one to measure ambient light, another that is blocked when a person is in front and there you go - when light drops on the one that gets blocked but not the other someone is standing in front. Probably.

Or combine PIR and photo resistor for better results - PIR detects motion, photo resistor measures drop in light level…

Another option would be mmWave presence detection sensors, but I never played with those.

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PIR sensors have no way to differenciate between distance, they’re only motion sensors. You’ll need to use a proximity sensor instead or a camera with some basic recognition built in (even at 10fps you’ll be fine for this use case). One more alternative is using a mmWave sensor, which is a presence device and will give you the best results.

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There are proximity sensors that act like a switch:

You might want more than one so you can fine-tune the detection area.

(Note: I haven’t looked at the specs of these to see if this specific model is appropriate for your RPi, you’ll want to check that :slight_smile: )

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As others have already mentioned, the PIR either sees or does not see. More likely a radar sensor… but even here it can be quite problematic to make it work perfectly.

Another solution is to put the mat in a preferred place and when someone steps on it… You can probably buy various solutions or make your own, even based on some simple door opening sensor.

Or try to do it with a laser beam, when the beam is interrupted…

Another option is a camera with object recognition in the detection field.

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