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IoT: Internet-Optional Things

I both love and hate the idea of "smart" devices in my home. It's tough to balance the convenience of being able to turn lights on and off automatically, and adjust thermostats with my phone, with the risk that all of my devices are doing evil things to my fellow Internet citizens. But, I think I've landed on a compromise that works.

I've had Internet-connected devices for a long time now. I've even built devices that can go online. At some point a year or two ago, I realized that I could do better than what I had. Here's a loose list of requirements I made up for my own "IoT" setup at home:

  • works locally as a primary objective
  • works when my Internet connection is down or slow
  • avoids phoning home to the vendor's (or worse: a third party's) API or service
  • can be fully firewalled off from the actual Internet, ideally through a physical limitation
  • isn't locked up in a proprietary platform that will either become expensive, limited, or will cease to exist when it's no longer profitable

My setup isn't perfect; it doesn't fully meet all of these criteria, but it's close, and it's been working well for me.

At the core of my home IoT network is a device called Hubitat Elevation. It works as a bridge between the actual Internet, and my devices which are actually incapable (for the most part) of connecting to the Internet directly. My devices, which range from thermostats, to lights, to motion sensors, to switchable outlets, and more, use either Zigbee or Z-Wave to communicate with each other (they form repeating mesh networks automatically) and with the hub. Again, they don't have a connection to my WiFi or my LAN, except through the hub, because they're physically incapable of connecting to my local network (they don't have ethernet ports, nor do they have WiFi radios). The hub brokers all of these connections and helps me control and automate these devices.

The hub—the Hubitat Elevation—is fairly inexpensive, and is not fully "open" (as I'd like), but has good integration abilities, is well-maintained, is compatible with many devices (many of them are devices compatible with the more-proprietary but similar SmartThings hub), and has an active community of people answering questions, coming up with new ideas, and maintaining add-ons. These add-ons are written in Groovy, which I hadn't really used in earnest before working with the Hubitat, but you can write and modify them to suit your needs.

The hub itself is mostly controlled through a web UI, which I'll admit is clunky, or through a mobile app. The mobile app adds capabilities like geo-fencing, presence, and notifications. The hub can also be connected to other devices; I have mine connected to my Echo, for example, so I can say "Alexa turn off the kitchen lights."

The devices themselves are either mains-powered (such as my Hue lightbulbs, baseboard thermostats, and switching outlets), or are battery powered (such as motion sensors, door contact switches, and buttons). Many of these devices also passively measure things like local temperature, and relay this data, along with battery health to the hub.

I'm going to get into some examples of how I have things set up, here, though not a full getting-started tutorial, but first I wanted to mention a few things that were not immediately obvious to me, and will get you off on the right foot, if you choose to follow a similar path to mine.

  • Third-party hub apps are a bit weird in their structure (there are usually parent and child apps), and keeping them up to date can be a pain. Luckily, Hubitat Package Manager exists, and many add-ons can be maintained through this useful tool.
  • There's a built-in app called "Maker API" which provides a REST interface to your various devices, which technically goes against one of my loose requirements above, but I have it limited to the LAN, and authenticating, and this feels like a fair trade-off to me for when I want to use this kind of connection.
  • There's an app that will send measured data to InfluxDB, which is a timeseries database that I have running locally on my SAN (as a Docker container on my Synology DSM), and it works well as a data source for Grafana (the graphs in this post come from Grafana).

Programmable Thermostats

My house is heated primarily through a centralized heat pump (which also provides cooling in the summer), but many rooms have their own baseboard heaters + independent thermostats. Before automation, these thermostats were either completely manual, or had a hard-to-manage on-device scheduling function.

I replaced many of these thermostats with connected versions. My main heat pump's thermostat (low voltage) is the Honeywell T6 Pro Z-Wave, and my baseboard heaters (line voltage) are now controlled with Zigbee thermostats from Sinopé.

Managing these through the web app is much better than the very limited UI available on programmable thermostats, directly. The Hubitat has a built-in app called "Thermostat Scheduler." Here's my office, for example (I don't like cold mornings (-: ):


An often-touted benefit of IoT is lighting automation, and I have several lights I control with my setup. Much of this is through cooperation with the Hue bridge, which I do still have on my network, but I could remove at some point, since the bulbs speak Zigbee. The connected lights that are not Hue bulbs are mostly controlled by Leviton Decora dimmers, switches, and optional dimmer remotes for 3-way circuits. Most of this is boring/routine stuff such as "turn on the outdoor lighting switch at dusk and off at midnight," configured on the hub with the "Simple Automation Rules" app, but I have a couple more interesting applications.


My kitchen counter is long down one side—a "galley" style. There's under-cabinet countertop lighting the whole length of the counter, but it's split into two separate switched/dimmed circuits of LED fixtures—one to the left of the sink and one to the right. I have these set to turn on in the morning and off at night. It's kind of annoying that there are two dimmers that work independently, though, and I find it aesthetically displeasing when half of the kitchen is lit up bright and the other half is dim.

Automation to the rescue, though. I found an app called Switch Bindings that allows me to gang these two dimmers together. Now, when I adjust the one on the left, the dimmer on the right matches the new brightness, and vice versa. A mild convenience, but it sure is nice to be able to effectively rewire these circuits in software.


I have an extensive beer cellar that I keep cool and dark most of the time. I found myself sometimes forgetting to turn off the lights next to the bottles, and—as someone who is highly sensitive to mercaptans/thiols (products of lightstuck beers, a "skunky" smell/fault)—I don't want my beer to see any more light than is necessary.

With my setup, I can have the outlet that my shelf lighting is plugged into turn on and off when the door is opened or closed. There's also a useful temperature sensor and moisture sensor on the floor so I can know quickly if the floor drain backs up, or if a bottle somehow breaks/leaks enough for the sensor to notice, via the notification system, and keep track of cellar temperature over time.

these lights turn on and off when the door is opened and closed, respectively

I also receive an alert on my phone when the door is opened/closed, which is increasingly useful as the kids get older.


Our house has an addition built onto the front, and there's an entrance room that is kind of separated off from the rest of the living space. The lighting in here has different needs from elsewhere because of this. Wouldn't it be nice if the lights in here could automatically turn on when they need to?

Thanks to Simple Automation Rules (the built-in app), and a combination of the SmartThings motion sensor and the DarkSky Device Driver (which will need to be replaced at some point, but it still works for now), I can have the lights in there—in addition to being manually controllable from the switch panels—turn on when there's motion, but only if it's dark enough outside for this to be needed. The lights will turn themselves off when there's no more motion.

Ice Melting

We have a fence gate that we keep closed most of the time so Stanley can safely hang out in our backyard. We need to use it occasionally, and during the winter this poses a problem because that side of the house has a bit of water runoff that is not normally a big deal, but in the winter, it sometimes gets dammed up by the surrounding snow/ice and freezes, making the gate impossible to open.

In past winters, I've used ice melting chemicals to help free the gate, but it's a pain to keep these on hand, and they corrode the fence posts where the powder coating has chipped off. Plus, it takes time for the melting to work and bags of this stuff are sometimes hard to find (cost aside).

This year, I invested in a snow melting mat. Electricity is relatively cheap here in Quebec, thanks to our extensive Hydro-Electric investment, but it's still wasteful to run this thing when it's not needed (arguably still less wasteful than bag after bag of ice melter). I'm still tweaking the settings on this one, but I have the mat turn on when the temperature drops and off when the ambient temperature is warmer. It's working great so far:

Desk foot-warming mat

My office is in the back corner of our house. The old part. I suspect it's poorly insulated, and the floor gets especially cold. I bought a warming mat on which to rest my feet (similar to this one). It doesn't need to be on all of the time, but I do like to be able call for heat on demand, and have it turn itself off after a few minutes.

I have the mat plugged into a switchable outlet. In the hub, I have rules set up to turn this mat on when I press a button on my desk. The mat turns itself off after 15 minutes, thanks to a second rule in the built-in app "Rule Machine". Warm toes!

When I first set this up, I found myself wondering if the mat was already on. If I pressed the button and didn't hear a click from the outlet's relay, I guessed it was already on. But the hub allows me to get a bit more insight. I didn't want something as distracting (and redundant) as an alert on my phone. I wanted something more of an ambient signifier. I have a Hue bulbed lamp on my desk that I have set up to tint red when the mat is on, and when it turns off, to revert to the current colour and brightness of another similar lamp in my office. Now I have a passive reminder of the mat's state.


An additionally interesting aspect of all of this (to me as someone who uses this stuff in my actual work, anyway) is that I can get a visual representation of different sensors in my house, now that we have these non-intrusive devices.

For example, you can see here that I used my office much less over the past two weeks (both in presence and in the amount I used the foot mat), since we took a much-needed break (ignore the CO2 bits for now, that's maybe a separate post):

As I mentioned on Twitter a while back, a graph helped me notice that a heating/cooling vent was unintentionally left open when we switched from cooling to heating:

Or, want to see how well that outdoor mat on/off switching based on temperature is working?

An overview of the various temperatures in my house (and outside; the coldest line) over the past week:


What's really nice about having all of this stuff set up, aside from the aforementioned relief of it not being able to be compromised directly on the Internet is that I now have tools that I can use within this infrastructure. For example, when we plugged in the Christmas tree lights, this year, I had the outlet's schedule match the living room lighting, so it never gets accidentally left on overnight.