I am searching for an occupation sensor to control lighting that can sense occupation even if the person is remaining still (watching TV in bed, sitting behind a computer). Are there any solutions for this application?
Much like the Holy Grail, people have been seeking for this for ages. There's no one good way to detect occupancy.
Most sensor systems are setup so they only detect changes over a short period of time. Otherwise you'd have to reset the things any time you moved furniture. Even something simple like moving an ottoman from one place to another would require resetting the baseline profile. So you can imagine that being less than ideal.
What's necessary is a combination of signals. There's nothing currently on the market that bundles it all up into a single "solution".
Our new TV has an idle sensor. If it hasn't seen an IR commands over an extended period it pops up a message indicating automatic shut off. If we've fallen asleep and don't see the message it automatically turns itself off. I worked in an office that at 10pm would blink the lights twice. If you were still in the office and wanted the lights to remain on you had to manually toggle the wall switch. Otherwise it'd automatically shut them off.
Passively detecting occupancy is a very hard problem. Tying it to detected activity is a lot easier, but certainly not 'simple'.
-Bill Kearney
A sensor placed in the doorway to the room could 'count' the number of occupants in the room. It would have to detect the direction of travel so that entering the room would add 1, exiting the room would subtract
I think the solution is going to be very much like our own multiple senses guide us to make decisions. A combination of PIRs, threshold detectors in doorways, sound detectors, vibration sensors and others, wired into a fairly sophisticated decision-making computer could do a reasonable job of assessing "occupancy."
The problem really is that any one sensor can get tricked pretty easily. No motion? A PIR will report an empty room. Two people walking out of a room through a large doorway side-by-side? That could fool an infrared beam detector at the threshold that counts exits and entries. The remarkable software that's finding its way into consumer cameras to detect faces and correct red-eye means it's not unreasonable to think tomorrow's occupancy sensor would be smart enough to know when people's eyes are trained on a TV.
I've wanted a simple sensor to fit under chair legs that detects and reports weight changes. Someone sits down? Send a signal that indicates a high level of probability that the user is still in the room, even if he doesn't move. If the occupant doesn't move for three days, call the coroner! I'll bet I could make something out of a old Hawkeye, some casters and some sort of piezo-electric strain gauge. Plenty of space under or behind most chairs and couches to velcro a Hawkeye and lead some wires down to the chair leg.
Precisely. There was a very interesting occupancy sensor described here a while back that used radio waves. It set up a "known pattern" with two antennas at opposite sides of the room (IIRC) and when that RF field was disturbed by humans beings interposed between them. Nearly 100 years ago Naval Research Laboratory engineers in DC saw that a ship passing between a transmitter and receiver on the Potomac river reflected a portion of the waves back to the transmitter.
Since radar's proved so useful in "sky and sea" occupancy detection it may have similar promise (albeit with much *lower* power transmitters) for home occupancy sensors. I know that my wireless 2.4GHz camera is very adept at sensing when I am between transmitter and receiver. The image breaks up something fierce!
I've got a similar set and any number of conditions are evaluated in the decision to turn it off. There's progress being made, it's just very slow and uncoordinated.
That's a good plan. In the two places I use X-10 Hawkeyes it would be nice if they could start just ramping the controlled lamp off slowly instead of plunging the room into sudden darkness. Hey, I could even do that via programming. Good idea, dude!
It's why we have ears, eyes, noses, nerve endings, etc. One sensor is too easy to fool. I remember back in sensory psych class learning about microsaccades. There are tiny movements the eye constantly makes because an image falling on the retina fades quickly. If you can truly immobilize the eye and stop the any saccadic motion, the image you see turns very quickly to gray. Without microsaccades, staring intently at an object would cause the image to vanish after a few seconds. Rods and cones respond only to net changes in brightness. PIRs behave in a similar fashion. As long as there is motion, there's detection. Maybe oscillating the PIR sensor is the solution! (-:
I'm not too worried yet. As Dan pointed out, I am recapturing a lot of that energy as heat and with subfreezing temps, that's a deal I can live with. The summer time might present a different picture and I've been seriously considering shutting it down during the months where electric prices rise sharply. That will solve the freeze up problem, too, since it's a lot easier to flush and clean the unit when empty. The final decision will rest on how much dehumidification it provides as compared to the floor unit I have. I guess I can determine that by pints of water removed at X relative humidity for each unit when the other's powered down.
-- Bobby G.
I agree.
And of course the paranoid among us would worry about the 'gubmint' using that to invade our privacy. What's next, your DVR with facial recognition being used by the feds to track down warrants? Heh, talk about "Minority Report".
My new Jeep does that to control the airbag in the passenger seating. But then it complains if you put a briefcase on the seat.
Help, I've sat and can't get up! But yeah, since the population's aging it would certainly be handy to have sensors dealing with health/safety.
And drive the wife batshit with the all the crap attached to the furniture... I know mine would throw me outta the house if I proposed such a thing.
What's really bad about all this is batteries. All this junk would end up requiring an endless loop of replacing batteries all the time.
Yeah, that was my point about having to recalibrate. It's sort of like the old joke about teasing the blind by moving the furniture. The RF pattern setups would require the ability to be retrained in an unobtrusive way.
If you came into the room, moved the ottoman and plopped down on the couch, what should the pattern be? How would it be smart enough to know the difference between than and, say, you and another person came into the room, you sat on the couch and the other on the floor.
This is also where occupancy sensors fail because of pets moving about. And while you might be able to get Fluffy to wear an RFID tag it's not likely you'd get people to do it.
The tracking necessary depends on so many factors as to be too expensive to actually implement. Day/night/electric lighting variations, heat/cooling fluctuations, auditory, visual, infrared, etc. By the time you factored it all in, the expense of it would be well beyond what the market would bear price-wise.
There's the rub. What's most tragic about all of this is most developer geeks are too young/workaholic to actually have a home, or one they visit on a regular basis. They don't "GO HOME" or live the same sort of like "normal" people do. Thus it's a bit hard to get them thinking about automating things in a real world sort of way. No insult intended, that's just the way things have been. The people that write the code don't actually have normal lives.
Yeah, when you let the automation interact in a "stupid way" you avoid having the people get pissed off when it fails to be "telepathic" to their needs. When people grasp the systems are 'dumb' they don't get their hopes up, or beyond reasonable expectations about how it works. Methodical, simple and predictable automatic systems are viewed for what they are, not what the users 'wish' they'd do.
I've been muddling around with it for a while. It boils down to steps like:
is someone there? is a 'person-related activity' in progress? is it during a given time or type of day? can I ask for guidance without bugging the person?
As in, did it detect your entry into the room, is the TV on, is it playing a two hour movie, is it past your predictable bedtime, is it a friday night or is tomorrow a holiday? Then the trick is in finding an unobtrusive way to let the occupant respond to override pending changes. My office lights blinking required getting up to flip the switch; not an unreasonable requirement. But that probably wouldn't fly for the couch potato watching a movie. The Tivo pops-up a message about it needing to change the tuner if it senses you've been using the remote. If you're not there or don't respond to the prompt it automatically proceeds. Using the overlay with the remote is reasonably unobtrusive as you're already likely to have the remote handy. But then there's no decent API to let other systems interact with it and doing overlay onto stuff like HDTV is not inexpensive.
Excellent point. Of course then there's also the problem of killing a fly with a nuclear bomb. Is that sensor too smart or too expensive to justify it's cost? Using RF in the home is going to be a real problem. If not just from the uncontrolled interference perspective but the human health impact. Too many folks whinge about the risks of "cancer" from their cell phones, the same complaints would undoubtedly get raised about occupancy sensors. But then again, folks would whine about anything new...
Damn that inescapble logic! Yes, it's not a bargain if it costs you extra to keep it frozen. When you've got a big family of growing children there's some justification to it. But otherwise it's sometimes cheaper to NOT get it in bulk. Go figure, literally.
Heh, that reminded me of when my furnace died. I was up in the office working close to a Sun server (an ancient 4/3xx series chassis). The box radiated such a tremendous amount of heat I didn't even notice the HVAC had died until I stepped away from the machine. Literally about four steps.
-Bill Kearney
What if there's more than one exit to the room? What if the person stood in the door, changed their mind an went back into the room? Entry/exit is too imprecise and error prone to be used alone.
I don't know if anything ever came of the project, but remember reading during the Vietnam war that the US Army was looking at a sensor for detecting the presence of human activity along jungle trails using bedbugs.
Bedbugs are apparently highly attuned to the smell of humans versus other animals and display a measurable degree of increased agitation when humans are nearby.
Of course you'd have to provide them with a real meal once in a while to keep them alive and maintain their interest. :-)
Regards, Charles Sullivan
I think the original post was for use in a bedroom -- most bedrooms only have one entrance. Even if there were 2, the "in-counts" could be "or'd" and the "out-counts" could be "or'd". To make it robust, the direction of travel would need 2 sensors and they could be set apart by maybe 3 feet or so. This might not be practical unless the doorway led to a hallway. Use modulated IR light beams for the sensors and TV remote control IR receiver modules to avoid problems with extraneous lights. I've seen sensors in museums and restrooms that probably work like that to shut off the lights when nobody is present. My guess is that someone could do all this with a basic stamp and a handful of other parts.
I don't know if it's anywhere near ready yet but I have hopes that eventually RFID technology may be able to provide a solution to this problem. Something small that could either be integrated into a watch or perhaps stuck onto the back of a watch. Hopefully this would allow tracking of yourself within the house similar to the way they are talking about asset tracking for industry.
Dave
I don't wear a watch, ring, or any other jewelry. And, when I walk into my house I empty my pockets within a few minutes on a side table or the bed headboard or the kitchen counter or ....
Gerald
Think cranial implant or some other appendage to your liking. :-)
1) DIY RF sensor : The People Detector at
"The People Detector (also known as the "Electric Field Proximity Sensor") is an micro-electronic based device that can detect the presence of both moving and stationary objects through solid materials. Its ability to operate through any non-conductive material permits complete invisibility. The sensor functions by detecting small changes in an ultra-low-power electromagnetic field generated between two remotely located antenna electrodes. Its range is adjustable from inches to over 12 feet."
I have a built board that may eventually end up in my porch sale although parts of my setup were left in the walls of a previous house.
And a schematic, bill of Material including component sourcing information, instruction manual, answers to Frequently Asked Questions and printed circuit board artwork are available for download.
Note the following description and caveat:
"The People Detector was developed in cooperation with the MIT Media Lab and in many respects can be described as a development tool for home automation enthusiasts. The multiplicity of calibration adjustments, which must be manually performed, can be confusing even to technical personnel"
If you can imagine trying to use the output of a theremin to establish the position of your hand(s), you can get a sense of what "multiplicity of calibration adjustments ... can be confusing even to technical personnel" might mean in practice.
2) RFID: There is a turn-key long-range HA RFID system for Crestron and Homeseer based on Wavetrend... Marc Marc_F_Hult
Three different commercial approaches that have been applied to HA come to mind:
1) DIY Electric Field Proximity Sensor aka "The People Detector", 2) long-range RFID, and 3) Bluetooth.See below:
1) DIY RF sensor : The People Detector at"The People Detector (also known as the "Electric Field Proximity Sensor") is an micro-electronic based device that can detect the presence of both moving and stationary objects through solid materials. Its ability to operate through any non-conductive material permits complete invisibility. The sensor functions by detecting small changes in an ultra-low-power electromagnetic field generated between two remotely located antenna electrodes. Its range is adjustable from inches to over 12 feet."
I have a built board that may eventually end up in my porch sale although parts of my setup were left in the walls of a previous house.
And a schematic, bill of Material including component sourcing information, instruction manual, answers to Frequently Asked Questions and printed circuit board artwork are available for download. But the device and pcb are no longer available commercially.
Note the following description and caveat:
"The People Detector was developed in cooperation with the MIT Media Lab and in many respects can be described as a development tool for home automation enthusiasts. The multiplicity of calibration adjustments, which must be manually performed, can be confusing even to technical personnel"
If you can imagine trying to use the output of a theremin to establish the position of your hand(s), you can get a sense of what "multiplicity of calibration adjustments ... can be confusing even to technical personnel" might mean in practice.
2) RFID: There is a turn-key long-range HA RFID system for Crestron and Homeseer based on Wavetrend3) Bluetooth: There is a 3rd party Bluetooth plug-in for HomeSeer.
... Marc Marc_F_Hult
This has been an interesting thread.
I have a x10 hawkeye in my family room, and granted there are times I'm watching TV and not really moving - usually snoozin! - and there is no motion detected for a period of time. But if I've awake, there's enough motion to keep retriggering it. Using a delay of say 16 minutes, I've had little problem.
While I don't have a motion sensor in with the computers, I'd really expect that there would be enough motion to keep retriggering there too.
The key with the hawkeye is to sense motion at all times - not just when dark.
As far as other triggers, however, it might be a bit too sensitive. There's been times that I've noticed the lights in the family room get turned on by a 10 lb cat that like to sleep on the back of the couch!
The interesting thing in the original post is "watching TV in bed". I guess something that's needed is a "person there and awake" mode, so occupancy isn't the only condition.
You've probably read that WalMart and other large chains are, or will be, requiring RFID chips attached to all their goods for automated inventory control. It won't be too long before all your clothing has an RFID chip sewn into it somewhere, and all you'd need do is register each item of your clothing with your RFID host processor as you buy it. Or maybe the processor could pick up on any RFID chip within range. (You'd have to have it reject RFID codes from furnishings in an unoccupied room.)
This would solve the problem in your household. (Unless of course you're a family of nudists.) :-)
And a small matter of programming. (-: The devil is in the details. Someone carrying a laundry basket in front of them through a narrow doorway is likely to register twice with only a beam interruption sensor. It's not a bad idea, but it's clearly got to be just a piece of the "is this room occupied" puzzle.
Automatic door failures have generated a lot of litigation, mainly because so many early models knocked over the frail and elderly, who often moved too slowly to be detected by single sensors. Look at any large grocery store's automatic doors (they're the primary defendants in such suits) and you'll see they'll have at least two (and often four) different types of occupancy sensors controlling their doors. One type of sensor simply isn't good enough (or failure-proof enough) to do the job reliably.
Pressure mats, light beams, PIRs and ultrasonic or microwave transducers are the ones I've seen most often in commercial establishments. They are designed to operate in an interlocking fashion and prevent the door from opening *into* a person for any reason. Stores that have vestibules (two sets of doors and a open area between them) are particular problems because people often pile up there inclement weather waiting for rides and so don't fit the designers expectations of orderly exit and entry by people walking at a normal pace.
It took knocking a lot of little old ladies over, but today's automatic door systems are quite highly evolved compared to the first generation of doors. There are probably an equal number of crushed children and dented dogs that have contributed to advances in garage door safety in much the same way as all those grannies. )-:
-- Bobby G.
I saw that one several years ago.
That was exactly my point about the problems of detecting what is or isn't an object whose placement should be considered when detecting "occupancy". Having to constantly tell this sensor what's a valid interruption of it's field just won't work in a residential setup. It might work well for a number of business settings but not in the home, at least not by itself.
None of this starts to be worthwhile until there's an 'omniscient' interface that can interact with the occupant without being intrustive. Trouble is that level of unobtrusive interaction does not come cheap or simple. Vision, voice, temperature, pressure, behavior patterns, schedules, sensors for these would have to all layer on top of each other before you're even close to being acceptable on a mass market scale. And that's not going to come cheap or without all sorts of nonsensical controversy about surveillance.
-Bill Kearney
I don't see that ever being viable in the home. I have no desire to have to keep a sensor on me. What if I'm walking bare-assed naked back from the shower? I'm supposed to have some widget on me? No thanks. Same deal goes because of style. If I am wearing a watch, which one? I've got a dozen different ones.
So no, I don't see on-person modules ever being an effective solution. Certainly not as a sole indicator.
While this may not be a solution for everyone, it may work for some. After I made the previous post I did some further digging. In addition to the interesting links posted by Marc Hult above, I also came across a similar package from
Dave
Future HA PC to Failsafe processor: "Naked man detected by image recognition software moving through house. Cannot confirm as occupant."
Failsafe processor: "Immobilize subject with Roomba/Taserbot and call police!"
Big thud!
If you had my dog in the shower with you naked, you'd have some serious questions to answer. How did you know her name? (-:
Most of us have assumed that when it comes time to for all of us to be chipped like dogs, you won't go stand in that line willingly! (-: Unfortunately, I believe that so many people *will* submit to having an implant that those who don't will lose out on some nifty technologies. Or government health and welfare benefits. Or security clearances. Or whatever. Got no implants? You can't enter the HOV-8 lane or whatever it will be by then. No implant? Get in the longest line at the airport.
If it's coming for pets, parts and packaged goods, it's coming for us, too.
And shouldn't this whole thread be renamed "occupancy" instead of "occupation" - there's a significant difference in meaning between those two words, at least to me.
-- Bobby G.
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