Presence or Occupancy Detection

rychlicki

New Member
Hi All,
 
I'm new to this board and I hope I'm posting this in the right place. If not please let me know.
 
My question has probably been posted and replied to before but did not see anything during my search...
 
Does anyone have a reliable method of detecting a persons presence in a room other than a motion detector?
 
Motion detectors are great for entering a room and turning on a light, etc.... but they are terrible at turning lights off when you leave.
 
I need a reliable method of telling when a room is empty and then turning off lights instantly, not after some motion sensor timeout that waste electricity because the motion sensor was set off when you left the room and the light stays on until the timeout.
 
Are there any reliable methods of room occupancy or telling when a room is empty?
 
Thanks in advance,
 
Victor
 
Hi Victor:
 
Welcome.  What you are asking is an excellent question. Unfortunately it is still a question without a perfect answer.
 
What you are asking for is also something EVERYONE would love. As you realize, sensors are almost ALWAYS motion sensors and not presence sensors. One big reason is that motion is fine for security sensors, and that is most of the market.
 
Some sorta ideas are to use an IR bean to count the number of people entering, and then subtract the number of people leaving. Not an ideal solution. Then there types of wave sensors that I have seen that can sense people, but often require repeated calibration. There is one where you put wires up two sides of a door, and it can sense someone between the wires. Unfortunately nobody wants to calibrate these things constantly and this sensor required that. Last, because of the Microsoft Kinect, in a year or so we may see a rather inexpensive sensor that can recognize a face, and thus a person. Primesense, an Israeli company and maker of the original Kinect is working on such a sensor. Primesense was recently purchased by Apple, so you know this is interesting technology. This technology uses an IR laser and a camera to do its things. You possibly could use many IR beams hoping someone would block at least one of them, but that is also expensive and would require adjustment if you rearranged your room.
 
Some final ideas are to use a camera. There is technology where a system can detect when someone is in camera-sight. Unfortunately this is not an inexpensive sensor. And you could use something like the Bluetooth LE fobs that you can buy for about $30, but you would need to carry the fob to be detected, and the accuracy is not great. You might be detected when you are not even in the room.
 
Many years ago I needed to build a sensor to detect if someone was on a bed or not, to control the ceiling fan in our bedroom. Even that was a hard task.  I settled on a device on one of the legs of the bed to detect weight. It works most of the time. I tried other means, including an IR beam, but nothing was really reliable. 
 
 
This is a very hard problem to solve, with no great answers yet.
 
Why not use a pir occupancy sensor? Yes, it is a motion sensor but used very fast response times and cheap. It's main purpose is for lighting control. I use them throughout my home and they do a good job for me. My automation control is managed via a Vera 3. I choose not to burden my M1 with much automation, and Vera has way more options anyway.
 
My sensors turn lights on/off in my rooms and outdoor lights. It allows me to monitor where people are in my house. I also used them for double duty as a security motion sensor during certain house conditions as well. 
 
Thanks all for the responses. I really appreciate it...
 
I took a shot at home automation long ago when X10 first came out, and had the same issue. You are all basically telling me what I feared most. That there is still no good, inexpensive, and reliable tech for detecting people or occupancy (versus detecting motion).
 
I had hoped that the 15+ years that has passed since then, would have resulted in produced new technology in this specific area.
 
Back to square one. At least for now. Hopefully Primesense will solve all our problems in this area.
 
Thanks again!
 
Victor
 
Victor,
 
Well I don't know what you consider inexpensive but the units I linked to work very well.
 
Motion detectors are great for entering a room and turning on a light, etc.... but they are terrible at turning lights off when you leave.
 
I need a reliable method of telling when a room is empty and then turning off lights instantly, not after some motion sensor timeout that waste electricity because the motion sensor was set off when you left the room and the light stays on until the timeout.
 
Are there any reliable methods of room occupancy or telling when a room is empty?
 
I use ceiling mounted wired sensors (relatively inexpensive) and they were on a timed shut down.  It was fast enough for me and I doubt very much that it used that much electricity.
 
Here the follow the motion at night lighting was low on the WAF.  Wife wanted to be able to enter a dark room and keep the lights off.
 
Now I just shut off the switch when I leave the room; but it was fun to play with. 
 
Yup for a while when the little RFID devices came out with the Homeseer software plugin folks were tagging their wives, pets, cars and children. 
 
Only issue was that you couldn't get telemetry from the tags.
 
Today you can purchase "cloud" enabled tags and watch with your cell phone. 
 
I am not sure how much telemetry you would get inside of a home with the tags.
 
Motion detectors are certainly not the best "occupancy" detectors whether they are called motion detectors or occupancy detectors. If you sit on a couch and don't move, then they go off, but obviously the room is still occupied. And when you leave the room, they say the room is occupied until they time out, when the room obviously ISN'T occupied. Why people believe that these devices which are wrong half the time are "good" for this purpose, is beyond me.
 
I got into the RFID craze with HomeSeer many years ago like pete_c  I still have some of those RFID tags on my trash can. That was certainly an expense waste of time and money, and I still wonder where that guy who was selling those RFID devices was getting those things from?  He seemed to disappear of of a sudden.
 
The AngelBlock devices look interesting, but like all Kickstarter promises, I'll beleive it when I see it. And I'm not sure if having to carry an RFID fob around is a good solution, but its probably the best one. I hear that Bill Gates did that in his smarthouse, but he likely had the cash to also install LOTS of receivers as well.
 
You do not want motion detectors used for security purposes to be too senstive or you get false activation.
 
On the other hand you want occupancy\vacancy detectors to be very senstive - so small motions retrigger them.
 
I've used the ones listed and they work very well. Yes it's possible to stay still enough that they don't retrigger but in normal use you move enough to keep them active.
 
Try them before you judge them.
 
Yup still using the old Homeseer CheaperRFID stuff for three vehicles.  Works 99.9 % of the time just fine for me with one receiver in the garage, one in the attic attached to an inverted scanner antenna and another one in the middle of the house buried in a wall. 
 
There were a lot of stated issues on the Homeseer site with the use of the receivers, placement of antennas, signals always dropping et al. 
 
I played some with my devices / antennas tweaking some.  I would say though they are worth $40 and relatively inexpensive relating to what they can do. 
 
The devices are used for status triggers and would work just fine turning on the garage lights at night.
 
The RFID units in the cars are in the headliners next to the dome lights and work fine off of the 12VDC of the automobile and have not drained the batteries to date.
 
I started initially purchasing them from the seller on Homeseer; then went to the source in China and initially did bulk buys very reasonably priced.
 
http://www.ananiahelectronics.com/
 
The newer ones now do have telemetry and he is selling bluetooth modules that work the same way these days. 
 
I will probably migrate my RFID stuff to the receivers with the hard switches built in as I do not see any interest in writing a HS3 plugin for these devices at this time.
 
pete_c said:
Yup still using the old Homeseer CheaperRFID stuff for three vehicles.
The CheaperRFID were the ones that actually worked. I had the expensive one before that with the expensive receivers and the tags that had batteries that only lased a year and were non-replacable. If you had multiple receivers it could even use signal strength to approximate the location. When it worked it did work great but the plugin had bugs that were never fixed.
 
Many of the motion detectors in my house have both microwave and passive IR. They have a terminal that you can toggle from "motion" mode to "occupancy" mode where it is would be super-sensitive. I have all these terminals wired into my panel so it turns the detectors to motion mode in AWAY and occupancy mode otherwise. But still very sensitive motion detectors are still not true "occupancy" detectors.
 
So they motion detectors have an extra pair for a "occupancy" mode? 
 
Are you running 6 wires then to the combo occupancy / motion sensors?
 
I actually did it with 4 wires. 2 for power, 1 for this setting and 1 for not ready/secure.  I had to wire it a bit different in the sensor but it works.
 
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