Pressure mats work well in hospitals, beds and wheel chair applications. But they are bulky and i am sure nobody would want a pressure mat on their fancy dining chairs
I propose a sensor that is probably as big as a thumb and you can place it under the chair right at the edge. Implementation can be done in many different ways , but as long as the sensor detects proximity or change in capacitance ,Its state will be “occupied”… Otherwise it will be “empty”… Any other implementation ideas?
(ActionTiles.com co-founder Terry @ActionTiles; GitHub: @cosmicpuppy)
There’s work on detecting room occupancy, including accuracy to number of occupants in a room, using measurements of radio wave (RF) interference. Some of these techniques even work through walls.
I’m tempted to think that some sort of high-frequency or RF pulse would definitely respond back to the sensor with a distinctly different pattern when a chair is unoccupied vs. occupied. Certainly worth an experience … if you can decide on what type of emitter / receiver hardware is worth testing to start.
This might go outside the boundary of what you’re trying to do, but I thought about using an Arduino with ThingShield and a simple 5v motion sensor to create some sort of presence sensor just for a single room or a desk area. You could write the code so that it reports motion events based on just a few seconds of motion/no motion, but wait for up to 5 minutes or so without motion to mark the room as not present.
Room occupancy based on a single motion sensor tends not to work in practice. Zone detection (multiple sensors) is good for turning lights on, but can still be tricky for triggering lights off.
The most accurate for room occupancy is probably a double trip beam where you can figure out which one tripped first and so distinguish coming from going.
Discussion of all of these here:
For a chair sensor, it depends on the exact use case. I disagree that pressure mats have to be bulky–they can be very thin and small, just a strip under the cushion. Coaster size, even. Often used in amateur robotics. Easy to make as well.
But certainly there are many use cases where an accelerometer or vibration sensor might work as well or better.
Got it - thanks for providing such a quick & detailed response. I’m actually trying to figure out how to create a wireless enuresis sensor for the elderly. I’ve found a few sensors (which I assume are really just moisture detectors) but none seem to already be zwave or zigbee enabled (out of the box). Here’s a few I’ve found & am trying to determine if they’ll work with the contact sensors you’ve mentioned.
Yes, i think all 3 should work. Just run the 2 wire leads to the contact block. By default it will show open/close and not wet/dry but you can make some minor tweaks to the devicetype if you need it to show wet/dry or you can just use the apps that come SmartThings to be noticed when it closes… cause then its wet
I think our need is different but I use a SmartThings sensor on my recliner. I have it mounted to the foot rest. When I opened the foot rest it fires an event that turns off a light that glares in the TV then back on when lowered.
Just starting to drink my coffee, so the brain has not engaged yet.
HOWEVER, the first that that Female Brain did say was that there seems to be another path you want to explore.
As a woman with a cold nature, I deplore cold chairs…brrrrrr.
My purse can weigh as much as a newborn elephant.
With that being said, what about a temperature probe embedded seat. A wire running from a ST sensor might detect enough change in temp if it is taped down across the both cheeks/thighs. A downside would be chairs that receive sunlight.
Maybe a command that said "If temp rises at least X° within Y minutes of motion. ???
There are a TON of these types of sensors, but they are not easily integrateable into ZWave or SmartThings.
We have done some work with Creatability Inc that actually did take a wheelchair pad (used to alarm if someone tried to get up or fell put) and tied it into a ZWave sensor. We are using it to track how often a patient stands as part of his therapy.
@ashutosh1982 I been tossing around this idea of chair presence in regards to dining table lights and thought instead of putting the multi sensor on the chairs how about to monitor vibrations on the table when people put their elbows or arms on the dining table and it could turn on dining room lights. It would definitely save money, and could alleviate false positives if chairs are bumped accidentally. Thoughts on this guys?
My usual concern with occupancy detectors to turn on lights applies: me in a wheelchair.
I realize people can make their own decisions about this (literally) edge case for their own homes, but anyone considering these kinds of systems for hotels, restaurants, and other public accommodations does need to take this into account. So just thought I’d mention it before you start planning investor presentations.