Simple (10/20/2010)

(Originally posted on October 20, 2010)

“Simplicity is the ultimate sophistication. “ – Leonardo da Vinci (maybe?)

I couldn’t pass up the opportunity to use a quote from L. DaVinci as an introduction to this blog post. But it’s really does set the right tone for a topic that’s been creeping up behind me on pad-feet, creaking the floor boards and occasionally breathing a little loudly. It’s always been there, but now it’s time to write about it.

A main theme for home automation should be, I think, to add value – in terms of convenience, security, energy efficiency, etc – while simplifying. Put another way, if you bring a new scenario to bear, don’t do it in such a way as to add complexity. Just add value, not complexity. Hold the complexity! Or make something simpler than it was.

It’s hard to make something simple, or simpler, while adding cool new functionality. Another quote is due:

To paraphrase Einstein (“simply” because I can):

“Make things as simple as possible, but not simpler” - Einstein (here)

Some questions to ponder when considering adding a new scenario:

  • How “natural” does the new scenario seem to the average user?
  • How much “training”, if any, is required?
  • How much of what the user already knows can be used to leverage the new scenario?
  • How robust is the scenario in the face of unexpected user actions or input, perhaps using existing controls or devices? Or other failures (such as power failures, loss of internet connectivity, etc)?
  • How are existing scenarios changed?
  • What additional “workloads” does the new scenario introduced for the user?

For example, some considerations when installing light switches that can be controlled via Home Automation software:

  • Do the switches operate like ordinary switches? Will users just “know” how to use them, because they operate just like other switches around the house?
  • What “value” are you introducing with these fancy new switches… is it for energy conservation? Security? What plan will you put in place to avoid confusing or frustrating users, or, worst-case, leave them tripping in the dark, feeling the walls for the switch for the light that just turned off for some reason?
  • If the HA software is programmed to turn the lights off under certain conditions, how will users react? Can this automation be over-ridden?
  • If the HA software is programmed to turn the lights on under certain conditions, will it also have a plan to turn them off (to conserve power or reduce user workload)?

Consider a (newer) Z-Wave light switch. One of the things I like about Z-Wave is that my controller software (Homeseer) can quickly detect when the user turns the switch on or off (see note 1). This means that I can fire events based on a change in the state of the switch. So I can implement a timer for the switch: if the user turns on the light, I want it to be turned off in, say, 20 minutes, because people in my house don’t know how to turn off lights (or so it seems). So far, so good. But, if someone turns the light on and then off 5 minutes later (that would be me) and THEN turns it back on a minute later, that 20 minute timer needs to be reset. It takes some scripting to make this happen (to clear out any pending “off” events for that switch).

This is an example of using some extra cycles (in the form of additional scripting) to hide the complexity from the user and build in some robustness. It’s also an example of the importance of 2-way communication between devices. It’s hard to create a smart scenario where unpredictable humans are involved if the controls involved aren’t able to communicate bi-directionally. Early Z-Wave devices, and earlier technologies, such as X-10, could not do a good job of keeping the HA software in the loop when the state of the device changed. If the user could turned on a light, the HA software might not know it, or might not know it for several minutes. If you were interested in adding value with these switches, it had to be done carefully to avoid frustrating the user.

Another example: what happens when you “automate” the A/V stack in your living room employing the usual approach of programming a fancy universal remote control (see note 2)? If my household was any indication, you’re introducing a new world of hurt. It seems that the usual approach leaves out the possibility that the user might have the audacity to actually touch the equipment, or perform a step in some order other than what’s been prescribed. This is usually because the typical remote control communicates in 1 direction only: it talks, but does not listen. It has no clue as to whether those commands have been correctly received, or whether it’s own model for the state of the components it thinks it’s controlling is accurate (see note 3). If the hapless user happens to, say, turn on the DVD player by pushing the power button on the player, in order to, say, insert a DVD and then picks up the universal remote to “Play DVD”, confusion results. The hapless universal remote, not knowing that the DVD player is already on will likely send a “power toggle” remote control signal to the DVD player, which will promptly turn if off. The remote is none the wiser. The user, though, is sure that something is screwed up. In an ideal world, the remote and the controlled components would talk to each other. In a slightly-less but still workable world, all component manufacturers would implement discrete remote codes for “power” commands and the like – not toggle commands.

In our house, we’ve moved beyond universal remote controls. At some point, it struck me as to how much of a compromise they represented, in terms of the user experience. Instead of using the remote that came with the component – DVD player, game console, tuner, etc – we were trying to shoe-horn all of the specific functions into a single, large, oddly-shapped remote that also tried to control the components using a 1-way protocol.

It slowly dawned on me that I could take a contrarian approach: if you want to watch a DVD, why not pick up the DVD remote and just use that remote for everything? That remote obviously already has a power button. And, the kicker is, it also has volume up/down buttons – presumably because it can control receivers from the same manufacturer or be pressed into service as a universal remote. So everything one needs to watch a DVD – power, volume, transport, and other DVD-specific functions – are represented as buttons on that one remote. So why not design a DVD scenario around that DVD remote? Similarly, the game console remote had all the buttons one needs to use it as well as a set of volume and mute buttons. Well, this is odd. Let’s go with it.

The approach I took was to reliably and in real-time mirror as software variables in the HA software (virtual devices in Homeseer) the power state of each component. If the DVD player was turned on, I needed the corresponding “DVD Power” virtual device in Homeseer to change instantly to “On”. Ditto the Xbox and any other source components. This was important to get right in order to handle the situation where a pesky human touches something in the A/V stack to, say, switch out a DVD. It took a while to figure out how to do this. For now, I’ll summarize it as follows:

  • DVD player: my particular player, a Sony BluRay player, sports a USB port on the front. When the player is powered on, that port is powered up. I built a simple circuit to sense when +5 volt signal is present at that port and change the state of the “DVD Power” virtual device in Homeseer to “On”. When the +5 volt signal is removed, the virtual device state is set to “Off”.
  • XBox: took a bit of work (and voided the warranty!). The Xbox also has USB ports, but these remain powered on even when the Xbox is “off”. Foiled! So the trick I used for the DVD player wouldn’t work here. I did, however, find a way to tap into the wires leading to the fans, which are fed a varying level of voltage when the console is on (presumably depending on how hot the console is). I built a simple circuit to detect when any positive voltage is present on the fans, and update a “Xbox Power” virtual device in Homeseer accordingly.

Once I had power state variables I could rely on, I was on the way to implementing this “pick up just the remote for the source you want” scenario. If you want to watch a DVD, pick up that remote and hit the power button. The DVD player will turn on, and Homeseer will take note of it: it will run some additional scripts to turn on the Receiver and the Monitor (which entailed making use of the RS-232-based command sets offered by those two components). Enabling the use of the DVD remote’s volume up/down buttons took more work, involving an PC-based IR receiver/transmitter (the USB UIRT).

I’ll post a more detailed explanation of all this in a follow-up post. But the bottom line is that it’s all working now. The existing controls – the remotes, the buttons on the components themselves – still work as expected, and in fact complement the new scenario. The universal remote control is packed away in the closet, beeping now and then as its battery fades.

A final example involves a scenario inspired by a contractor who was working in our bathroom. He kept saying, “Get it out! Get it all out!!”, when we talked about sizing the exhaust fan. He really (really) believed in the importance of clearly the bathroom quickly of steam from the shower. It not, you run the risk of mildew or rot and the resulting structural problems. Always run the fan while showering, and then for 10-15 minutes afterwards.

In my house, however, few other occupants really took this message to heart. If they remembered to turn the fan on, it was typically after the shower was over and the walls were already dripping with condensation. And no one remembered to turn it off after the required 15 minutes, thus triggering complaints from me about noise and wasted electricity.

I moved the fan to a Z-Wave controlled circuit, and scripted it so that it would turn off automatically after 15 minutes. That’s a good start, but doesn’t solve the problem of getting people to turn the fan on during the shower, not after it’s over and the place is already fogged up.

What would the average user expect when asked to describe a “automatic shower fan”? I’d say this: the fan should turn on automatically when someone starts the shower, and not turn off until 15 minutes after the shower ends. That’s a great goal statement. But, as you can imagine, from an implementation perspective, it seemed like a downright gnarly problem to solve. But it was solved, albeit with some extra hardware (Ha7NET hub), 1-Wire devices, and more complex-than-usual scripting). The “simplest solution” has been working well for a couple of years now. More on that later.

In closing: I like ThingM‘s motto: “Smart devices make things simple”. I think that’s a good criteria to evaluate when deciding whether your ‘bots and automation plans are actually adding value.


  1. If I’ve set it up correctly. Due to various issues with various versions of Homeseer, it’s not a given that this is always the case. More on this later.
  2. I’ve owned two Logitech Harmony Universal Remotes, but, alas, I can’t recommend them. Both have ended up being disappointed for various reasons… the programming experience is awful, but it pales to the issues caused by the poor product build quality, hardware flakiness, and support. The most recent model I owned is the Harmony 890, which can send signals via IR or RF. If you’re considering one of these, please take a look at the reviews on Amazon first. On paper, it showed promise…
  3. Too often, component manufacturers take the lazy approach to the power button on the remote, by implementing it was a toggle. Pushing the “power” button on the average remote often sends a single command which the component interprets as this: “if you’re on, turn off; if you’re off, turn on”. This means that the average universal remote must remember if a component is on or off in order to implement a scenario like this: “the user is currently watching a DVD but would now like to play a game on the game console… so, turn off the DVD player and turn on the game console”. If the remote thinks that the game console is already on, it will skip sending a “toggle power” remote code. If, on the other hand, the game console has discrete “power on” and “power off” codes, the remote can confidently send “power on”, which do nothing if the game console is already on. I think that “discrete codes” are one of the marks of a component/device that’s designed to be system-integrated.

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