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Topic: Is this possible? (Read 1 time) previous topic - next topic

jpwfku

Hi all,

Ok so I've been looking around for quite some time and frankly I'm overwhelmed with the methods and components to make this work. What I'm trying to do is make a motion detector that will count the number of people in my house (i.e. my roommates and friends). I want this motion detector to be able to count up and down, such as when someone enters or leaves, and give me an exact count transmitted to my computer wherever I may be. I have been looking at the UNO board and ethernet shield for this. Would this configuration work, or should I look at other components?

johnwasser

The hard part will be maintaining a good count.  It is not easy for a sensor to detect the difference between one person entering and two people entering close together.  Perhaps a multi-touch pressure-sensitive mat near the door(s) could count feet entering and leaving.  That could get confused by rolling luggage or bicycles.

Perhaps you should build a turnstile.  :)
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zoomkat

Quote
What I'm trying to do is make a motion detector that will count the number of people in my house (i.e. my roommates and friends).


If you figure this out you will be very popular. The home automtion world has been looking for the same type of occupancy monitoring for years, and so far there doesn't seem to be anything that is simple, easy, or inexpensive.
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)

Grumpy_Mike

Back in the 60s I worked on a project for counting people upstairs in a bus. It used pressure pads on the stairs. The counting bit is no problem, getting the correct sensor information is.

This is one of those projects that sounds easy until you come to do it.

tigerbomb8

#4
Jan 12, 2012, 09:08 am Last Edit: Jan 12, 2012, 11:22 am by tigerbomb8 Reason: 1
i wanted to make something that would recognise if someone was walking in or out of a room. it was just two lasers on ether side of the door way, pointing at two photocells. when someone would walk in one beam would be blocked then the other. depending on which one was blocked first you could tell if they were going in or out

GoForSmoke

Get them to wear RFID tags?
I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

tigerbomb8


Get them to wear RFID tags?


no because they would need to walk with in an inch of the reader

Grumpy_Mike

It depends on what sort of RFID tag you use.

liudr


Back in the 60s I worked on a project for counting people upstairs in a bus. It used pressure pads on the stairs. The counting bit is no problem, getting the correct sensor information is.

This is one of those projects that sounds easy until you come to do it.


Was that for safety purposes? Avoid moving the bus when it's top-heavy?

By the way, I think of Tom Cruise as a good example of occupancy detector/avoider in his movie series. So maybe weigh the people as they enter. You can detect weight with strain gauge and IR sensor together. Still, it sounds just hard. The weight variation is too large among people.

GoForSmoke



Get them to wear RFID tags?


no because they would need to walk with in an inch of the reader


A store down the street has RFID tagged products and metal tube type detectors at the doors. They pick up the un-wiped (aka 5 finger discount) tags going through with no problem.

But I was thinking of active tags that could be read in any room. A tag count would be easy enough and if the same people always had the same tags you would know who as well as how many. You could easily enough detect if anyone was going around without a tag too.

I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

wizdum


i wanted to make something that would recognise if someone was walking in or out of a room. it was just two lasers on ether side of the door way, pointing at two photocells. when someone would walk in one beam would be blocked then the other. depending on which one was blocked first you could tell if they were going in or out


This is how the DOT road sensors work (although they dont use lasers). I'd go with this plan, its simple and effective.
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Grumpy_Mike

Quote
Was that for safety purposes?

No it was so the driver and passengers could see if there were any seats available upstairs and so prevent a lot of up / down stair movement. In those days smoking was permitted upstairs in a bus but not downstairs so there was a lot of demand for seats upstairs. People would to go up stand at the top and look about in the mean time a queue of people developed on the stairs preventing anyone from descending.
This was in the days before TTL logic even and we made a 76 stage ring counter on a PCB that was about 2 ft square and had a form of dot matrix display made from side illuminated acrylic with holes drilled in.

jpwfku

Thanks everyone for your inputs. I like the laser option, but I wander if a two garage door sensors would do the trick?

liudr


Thanks everyone for your inputs. I like the laser option, but I wander if a two garage door sensors would do the trick?


Yes. You put them in a narrow corridor one after another. People entering will trigger sensor 1 then sensor 2. People exiting will trigger sensor 2 then sensor 1. The logic is the same as rotary encoder so you can get some code that is for rotary encoders.

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