Door Sensor for Height and direction detected

The idea is to have a door sensor mounted above every door or entrance to every room…measuring the height of whatever passes underneath. Since the people in a common household are not all the same height, this works to identify individuals and whether they are coming or going out of a room/space. The attached pdf suggests an expensive sensor, but I think it could be done with a cheap wireless chip like ESP8266 and a simple ultrasonic distance sensor like HC-SR04.

It would need to be able to identify a person by height and a room by what sensor was triggered and store this information for retrieval. This would allow crazy triggers based on individual persons preferences. I could see asking my smart speaker… “Where is Curtis?” and being told “He went out the back door” or “He is in the downstairs playroom”

Such a system could work as a security system if non-recognized people came through the door, you could get a SMS from WebCoRE asking if this was an approved entry.

Autistic kids or Elderly persons could be monitored without “tagging” them with a presence device or using cameras to watch them (kinda creepy)

Such a device would change the home automation world if it was made reliable.

Unlike fingerprints, iris patterns, facial characteristics… isn’t "height’ a rather weak identifier? While I suppose, statistically, within a household of a few people, the chance of a mismatch is relatively low; I can’t help but wonder how this accounts for the non-trivial height variance based on stride, let alone bending over or standing on toes, wearing high-heels, …

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no doubt. Reliability requires 7cm difference in height to be reliable and might not be entirely successful. Although the paper quoted suggests that accuracy goes up as you keep historical records and watch them taking a path through the house… going to a basement bedroom at my house would require passing 5 thresholds at each point if the subject is 42 inches tall, it is probably my son… while taking that same path but going to the laundry is probably my wife, even if they were the same height.

This seems like a lot of trouble for very little accuracy. Facial recognition would be better.

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Facial recognition requires cameras, which introduces a privacy issue.

At our house the problem is the number of people coming through. We are three housemates, We each have friends and family, plus health aides. As @tgauchat said, it just wouldn’t be a unique characteristic for our household. But it might work for some people, choice is good. :sunglasses:

At the present time, most analysts believe that within five years we will have devices that can identify people by listening for their heartbeat. That does tend to be quite distinct, but without the same privacy issues as a Camera based system.

So I think we’re going to get to something eventually which doesn’t require wearing an identifying device, it’s just not clear which technology will get there first.


Yes, please share. I’ve listened to a lot of heartbeats but it never would have occurred to me there is something unique enough about an individual’s heart sounds that a computer could use that to identify someone.

The tech exists for a wearable, and it’s being used in some enterprise applications. It didn’t catch on for consumers the way they had hoped because the device is a little too fragile.

The following is a more generic scientific study on how it might be used to:

There’s a lot of work yet to be done, but it’s an interesting idea.

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I could see the ECG waveform as a biometric identifier, though still tough to pull off I’m sure.

To get a device to listen for an individual heartbeat that enters a room seems like an additional huge challenge.