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.

Child Automation and our Yale Deadbolt

When we get home, one of the kids asks for the house keys. The first one to ask gets the keys and gets to unlock the door. They love to unlock the door, so it’s frequently a race. I’ve been thinking it was time to give them their own keys, but its really hard when they can’t yet hold onto the same library card for more than a year. Stashing a key outdoors didn’t fit my sensibilities.

In exploring the options, I found a wide variety of locks. Push buttons. Numeric keypads. Bluetooth. WiFi. Smartphone Apps. Key fobs. So. Many. Options!

Some I was able to weed out straight away. Requiring a smarthphone is a non-starter. For that matter, requiring that we carry anything seems so last century. If someone gets locked out of the house naked, absent their sniggering sibling on the other side of the door, they should be able to get back in.

I found almost exactly what I was looking for in the Yale YRD240-ZW-605. I can easily program a unique key code for each family member. I can add a key-code for the neighbor to feed our pets when we’re on vacation. It has a Z-Wave radio built-in which pairs with my SmartThings hub. I can pull out my phone and lock/unlock the front door from anywhere. Instead of the far-less-secure key backup, this version has a 9-volt battery port which serves as the spare key.

[amazon template=image&asin=B00HS1O5NM]

The Wife Acceptance Factor of this lock is very high. When she walks out the door, she just waves her hand at it and it locks the door. When she gets home, keying in the code is faster and easier than fishing her keys out of her purse. If her phone is already out, she can unlock the door on her way towards it.

The kids adore it, but the entry routine is  a little different than I expected. Before someone unlocked the door and we all piled through. Now one child enters their very own Simerson Secret Door Society code, enters, and then deadbolts the door. Then the next child enters their code and enters. When I pull into the garage, they run out the garage door so they can enter via the front door. Shucks, they still lock themselves outside just to use their secret code and get back in. I’m amazed that the batteries have lasted three weeks. The lock says it’s battery life is still 100%. Amazing.

home automation

I recently gave a presentation on Home Automation to a room full of engineers/programmers. I was asked several times to share the presentation.

The state of home automation has improved greatly since a decade ago when I threw all my X-10 stuff into a box and left it to rot. H.A. still requires an engineer/geek to set up, but it’s far better than a decade ago. It’s not hard to see that in another year or two, setting up home automation will be attainable by non-geeks.

the ROI on LED

Did you do a break even analysis yet? How long will it take you to recoup the expense?

The way to calculate break even (or Return On Investment) is to know roughly how much each bulb costs to use. To determine that, I built a spreadsheet that listed all 49 light fixtures in my house, the number of bulbs in each fixture, watts per bulb, lumens, and the estimated hours of monthly use. From that list, I picked the 24 most expensive bulbs to operate and replaced them with LEDs, at the cost of $217.


  • Halogen track lights are horrifically inefficient. Replace immediately.
  • Old transformers are terribly inefficient. Replace immediately.
  • LED track light bulbs are hard to find locally and horrifically expensive. Instead, buy direct from China.
  • Considering their lumen output, 4′ fluorescent bulbs aren’t that bad
  • The ROI is usually less than a year for bulbs used more than an hour a day

For the bulbs in my “top 24” list, the ROI period was less than 12 months, and that was purchasing the bulbs at late 2012 prices. Today I can buy most of those bulbs for about 30% less, so the ROI is even faster. Today at Costco, I purchased 850 lumen dimmable LED bulbs for $8 each.

Also consider that many of the bulbs I replaced were CFL. The savings in going from CFL to LED are much lower than when switching from incandescent, lowering my ROI. But the instant on, dimming, and improved light quality of LED bulbs make the switch worth while.

What LED’s do you recommend?

I recommend whatever LED bulbs cost about $10 for 850 or more lumens. I would buy them only at a local store with a good return policy. Out of 40 bulbs, I’ve had two fail. At $10/ea, they cost just enough that it’s worth taking them back for an exchange.

It’s worth noting that both my bulb failures were on the same power circuit as the 12v track lights, and I suspect the 12v power transformer played a role in their failures.

Did you bypass CFL altogether?

We used many CFL bulbs from 2009-2012. The light quality of the earliest ones was quite awful, so we confined them to areas where that didn’t matter. Price was never an issue, as Seattle City Light subsidizes them: a 6-pack of CFL bulbs has cost $1 for years now. As CFL bulb quality improved, CFL bulbs found their way into more rooms. But unlike LED bulbs, they never became good enough that we liked them.

Green built houses

With house prices and interest rates low, we are considering homeownership again. We have looked at hundreds of houses in the past year and found a half dozen that we really liked. What we haven’t found is a house we like at a price we like.

In 2011 we learned about three standards in the green building industry:

  • Passive House: limits household energy consumption to 120 kWh per cubic meter. A Passive House is very efficient and there are tens of thousands of houses built to this standard in Germany, Scandanavia, and Canada.
  • Net Zero: consume zero energy and zero carbon emissions annually.
  • Energy Plus: produce more energy annually than is consumed.

In 2011 we attended several green energy festivals. We toured a couple Passive Houses and the only Net Zero homes in the Puget Sound area. The cost of getting to net-zero is 15% more than building a traditional home. Our goal is to get as far as we can towards net-zero. A net-zero home has a monthly gas and electric bill of $0. Getting to net-zero requires reducing energy consumption through:

  • an efficient building envelope (super insulated, tightly sealed, oriented for beneficial solar gain)
  • highly efficient fixtures and appliances (LED lights, induction cooktops, solar water heaters, heat pumps)
  • a heat recovery ventilator (recover heat from ventilation air before exhausting it)

The other ingredient required to achieve net-zero is energy production. Solar has long (at least since the Chinese & Greeks oriented their buildings to face the winter sun 2,500 years ago) been the first answer for harvesting energy. Until the 1970s, the best available technology was exposing internal masonry to the sun. The thermal mass of masonry would warm up in the day and then give off the stored heat at night.

Using solar exposed masonry is still an excellent and highly efficient way to collect heat. The obvious limitation is availability of sunshine, which is often meager in Seattle’s heating season.

Retrofitting an existing house to achieve green building standards is more complex than building the house well initially. This has made choosing a house more challenging. I desire the ability to retrofit a house up to at least the Passive House standards. Some house designs make this more challenging than others. For example, I can’t easily change the orientation of a house to capture beneficial solar gain. Generally, houses are sited for the convenience of the builder rather than the long term benefit of the occupants.

In the meantime, we aren’t waiting for a new house to be more environmentally aware. We have reduced our household waste to less than one kitchen bag per week. The majority of food waste is diverted to my compost pile and the rest is recycled. I have replaced all our household lights with LED bulbs. In areas where lights were typically left on, I installed motion sensors with timers. We have a hybrid Ford Fusion and a Nissan Leaf, greatly reducing our gasoline consumption.

beat the heat, on the cheap

Our house sits high on a ridge, facing West towards Puget Sound, and the setting sun. From mid-day through sunset, our kitchen, dining room, and living room are bathed in sunshine, rising as much as 20°. All the windows have wooden blinds, but they are dark colored. Instead of reflecting the heat, they absorb it and radiate it into the room. They are effective at controlling light, but not heat.

Because high temps are rare in Seattle, houses here don’t have A/C. After the first day of last week’s heat wave, I took action. I did some research on cooling methods, including whole house fans, rigging up a cool air intake to my furnace’s intact duct, window films, etc. Because we rent, I can’t just start cutting holes in the house and moving ducts. So I settled on a less invasive (and costly) solution: box fans and window film.

I purchased two box fans ($15 ea) to place in windows. (Why do box fans not come in sizes larger than 20″?) The fans draw air in the shaded East side of the house, creating a cool breeze that pushes warmer air out the West side. Turning them on at 7PM is sufficient to cool the house down to 70° by bedtime. What a relief!

Window films have come a long ways since I last used them. Good film is now reasonably priced, uses water to ‘set’ the adhesive, and doesn’t require a ‘pro’ to get good results. Lowes had Gila Platinum Heat Control Window Film in stock so I picked up 4 rolls, enough to tint most of my 15,000 sq/in of West facing glass. I stripped the blinds off the windows and went to work. It took me about an hour per pane to apply the film, with half that spent cleaning the glass, scraping the crusties off, and cleaning it again.

The results are outstanding. Amazing. Phenomenal.

4:02 PM Jen: Wow the kitchen is much cooler!  Great idea and thanks.

We should not be surprised at how effective the film is, yet we are. The product fulfills the claims made by the manufacturer, and exceeded our expectations. And just when we thought it couldn’t get any better, window film qualifies for a 2009 Tax Credit.

home in Washington

Friday began at 4AM. By mid-morning, not a single boat had caught a fish and we hadn’t gotten a nibble. The four of us headed back with empty coolers and dampened spirits. But as everyone knows, a bad day fishing is still better than the worst day ____ing. At the docks, the warden shared that nobody was catching Salmon. That made us feel better about getting skunked.

On my way home, I stopped by the Alderwood Mall Apple Store. A couple Geniuses and I agreed that a bug in the latest version of Apple’s iPhone SDK (beta 8) caused my iPhone some irreparable harm. I walked out with a brand new iPhone and a $0 invoice. It’s nice to have a single vendor that builds the hardware, OS, and SDK. It is even nicer when that vendor stands behind it.

As I resumed homeward on I-5, a great song started playing on the radio. I cranked up the volume and sang along. Loudly. As I popped up over a hill the loveliest of images appeared. The day was sunny and bright without even a hint of haze. Which means that despite being 50 miles away, Mr. Rainier appeared so large and imposing that I paused to gaze at her majesty. It warms a part of my soul to be near the mountains.

On Monday, we caught fish. See the photo at right.

We made it to Seattle

Our migration to Seattle is nearly complete. We left Dallas on Monday afternoon and arrived in Seattle on Thursday evening, as scheduled. Our truck arrived in Kent, WA on Friday morning and was delivered this (Friday) evening. If all goes according to plan, we’ll be moved in with every box emptied and broken down by Sunday evening.

Extra springy

Since we enjoy springtime and it is nearly over in Dallas, we packed up our house into a truck today and drove NW to Amarillo, TX. Tomorrow we’ll drive through Albuquerque, NM and Durango, CO. Then we’ll drive the Colorado Skyway ending in Grand Junction, Colorado for the night. We’ll get to Seattle just in time for spring to arrive.