Motion Sensors

Thanks – very helpful!  I’m curious – what model of motion sensors are you using?  Have you had good luck with them?  What’s the battery life like? Is it practical to put them in pretty much every room of a house?

Every room? That depends on your budget. 🙂

Outside I have Aeon Labs Aeotec Z-Wave MultiSensor: (Motion, Temp, Light level, Humidity) which turns on the lights when motion is detected and it’s dark. I’m not doing anything with the Temp or Humidity yet, but they’re neat to have.

Inside the house, I have Ecolink Z-Wave PIR Motion Detectors. I currently have one in the kitchen, dining room, living room, and front stairwell (split-level). When it’s dark outside (see above) and motion is detected, GE Link bulbs turn on and light that area. I’m going to buy more because my son wants the lights in his bedroom to be smart too.

The motion detectors work fairly well, with limits. They are Passive IR, which is GREAT for battery life, but after tripping they don’t begin watching again for 4 minutes. To prevent going off when someone is sitting idle in the room, I find I can’t “trust” a lack of motion until about 20 minutes after motion stopped. I’ve read that some folks run these detectors in “test” mode, which reduces the 4 minute timeout to 10 seconds, at the cost of shorter battery life. I haven’t tried that yet, but likely will in the dining room. Believe it or not, sometimes my kids actually sit still while doing homework!

I also have a SmartThings SmartSense Motion Sensor that came in the kit with my hub. It usually senses motion and temperature, and after a month’s use six feet from the hub, it’s down to 66% battery. All the Aeon motion detectors are at 100% after a months use. I’m substantially less impressed by this ones reliability (which impacts the WAF) so it got relegated to the garage. I haven’t done any validation of battery life reporting, but there’s a good chance I won’t recharge this guys batteries.

One thing about motion detectors is they don’t detect us until after we come into their field of view. Duh, right? For the motion sensor inside the front door, this means the sensor generally doesn’t “see” us until the door has mostly opened and we’re walking in. During that delay, someone is invariably reaching for the switch at the same time the lights come on. That’s confusing, especially if they flip a 2-way switch and nothing happens. I could put another motion sensor on the other side of the door, but what I like better is…

the Ecolink Z-Wave Door/Window Sensor. I now have one on every exterior door. The second the door starts to open, the lights come on both inside and outside the door (if they weren’t already). The motion sensors are then used as occupancy sensors that turn off the lights after the area hasn’t been occupied for N minutes. A planned automation feature for the door sensors is to automatically yell at my kids if they’re more than N feet from the front door and didn’t close it.

The less “smart” but very useful motion sensors that I’m using are these Mr Beams MB726 Battery Powered Motion Sensing LED Nightlights. They aren’t smart in the Home Automation sense but they are much cheaper. They’re ideal for lighting up dark hallways and stairs where “light it up when I come, and turn if off 30 seconds later” is just perfect. I bought those because I have kids and a couple of our hallways didn’t have power outlets to plug in a motion-activated AC powered nightlight.

One last tangent related to motion sensing, but more on the “smart switch -vs- bulb” topic: With the smart bulbs, one limit is that if someone turns off the switch, the bulbs forget their dim level. A switch never loses power so it remembers. An advantage of smart bulbs is that at homework time, motion turns on all 4 bulbs at 70% brightness. At dinner time, motion turn on 3 bulbs at 50% brightness. After 9PM when the kids are in bed, motion turns on one bulb at 10% brightness. Switches act on all the bulbs or none.

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