I’m looking into motion sensors (mostly multifunction motion sensors, to be exact) and I was comparing the Fibaro eye with the Aeon 6 Multi Sensor. I’m trying a couple of the Aeon 6 because I need the humidity sensor but i began to wonder about the difference in actual use of what one can do with the vibration/seismic sensor in the Aeon 6 vs the accelerometer/vibration sensor in the Fibaro eye. Both are supposed to prevent tampering. But what might one be better for than the other? Are the basically the same or are they quite different in what they can do and what they actually are? I just can’t quite get my head around it yet. I’ll almost certainly add more motion sensors and I was thinking that if the accelerometer is better for some reason I could possible have a couple of each of the sensors. I’d love to hear your thoughts, experience’s, impressions, and ideas on the differences (or similarities!) of these two. Thanks so much!!
In home automation, Vibration detection is typically done by an accelerometer, so they’re the same thing technically. Two different devices might have different features through their UI, but that’s a separate issue.
In general there are three methods to measure vibration:
Displacement sensors, which are most often non contact proximity sensors – – if it gets knocked off place, it counts as vibration. These are used in machine tools a lot, where the exact alignment really matters, but not usually used in Home Automation.
Velocity sensors, which are used for big rotating equipment. Don’t really have any applications in typical home automation.
And everybody’s favorite, accelerometers.
As for what an accelerometer does in Home automation , it reports a bump, tilt, shake or repositioning of the device itself.
So people use it to tell when the laundry is done because they’re capturing when the device stops shaking.
They use it to try to capture a knock on the door because the knock vibrates the door slightly.
They use it to tell if a valuable object has been moved.
It’s used in fall detection as the device goes through a rapid shift in positioning.
So the reason it’s used as a tamper alert is it means someone is physically doing something with the device and that will either cause a shake, a bump, or an actual movement. This is also why earthquakes set off car alarms.
Some “old” shock detectors (such as from Monoprice) still literally use a magnet centered inside a coiled spring to induce a small electrical charge indicating to detect some vibration. This is not sensitive enough to detect a very slow movement (just a change in orientation… i.e., gravity).
“Newer” sensors use a 3-Axis accelerometer “on-a-chip”, which, literally, contains a microscopic pin or two between microscopic electronics that measure it’s strain or proximity to internal sensor. These are sensitive enough to record fractions of 1g … and some have ranges up to 6g.