Thursday, December 29, 2011

Competition: Nest Learning Thermostat: Teardown

Sparkfun published a nice article about Nest teardown.

I wonder if the battery is replaceable other than by "contacting technical support" (update: from the link below - no, it is not replaceable).

As usual, comments are as useful as the article if not more.

C Wire-less Setup

In particular, here's a link to an article describing a subtle problem: Undocumented Nest incompatibility with single-stage wiring. Incidentally, all three of three HVAC units I have do *not* have the C wire. Here's what Nest has to say:
Would it be a regular dumb thermostat with nothing but dry contacts, I'd fiddle with wires. With this device, I guess I'd go for their installation service if there is anything out of ordinary. Or spend more time digging the actual wire layout. By the way, DIY installation video doesn't even hint at this problem, which makes me think there'll be lots of pissed off overconfident DIY dudes with attitude killing their Nest and blaming the manufacturer for that. Their Returns & Cancellations page is mum about what is gonna happen if the thermostat comes back dead because of customer's fault, it'll be interesting to see how this gets handled.

Afterthought: Multi-zone Setup

I missed the How does Nest work if I have multiple Nest Learning Thermostats in the same home? article when I was writing the original review. Stark contrast with DZ approach: one relatively expensive control panel per user (optional) and lots of dirt cheap sensors vs. many expensive control panels. The other side of the equation, though, is Apple aesthetics, learning capability and ability for everyone to control the temperature vs. powerful, though not quite below-average-IQ-friendly scheduler and unlimited tinkerability (at high price of your involvement, of course). These products are for totally different markets, that's for sure.

Thursday, December 15, 2011

Early Access: DZ on Android

Home Climate Control on Android

Effective immediately, Android remote control application is available.

Visit the forum to find out more.

Monday, October 31, 2011

Competition: Nest Learning Thermostat

Nest Learning Thermostat

Brent brought the news about Nest Learning Thermostat. Mandatory review follows.


  • Supposedly good design and excellent workmanship.
  • Equipment check that is eventually done right. I wonder why nobody thought of that before, usually this information is buried deeply inside technical manuals (and good luck if you lose one).
  • Subtle interface cues to what is going on (I did this first almost two years ago, though).
  • Remote control. Guess this is the new fad.
  • Outside weather awareness.
  • Supposedly helps you saving energy. Gives you energy usage statistics.
  • Multiple thermostats working together.
  • Massive amount of documentation (go to support site and click on the arrow next to the "search" box without entering any search terms).
And to finish the panegyrics, here is a welcome thought:
I wonder if the largest effect might be getting people to voluntarily interact with the thermostat at all, thereby thinking about their HVAC more. The fact is that most of us only think about our heating and cooling systems when they’re not working. If we start thinking about them when they are, we could save more energy. The nest is so appealing to interact with that it might shade that in the energy-saving direction.
If for nothing else, creators of Nest deserve high praise for this effect alone.


First and foremost, this is just a banal thermostat. With it, you inherit all problems inherent to banal thermostats (a comprehensive explanation is at our FAQ). The main issue, again, is:
Thermostat makes itself happy. It doesn't care about you. It is not where you are.
In other words, it didn't cross the fundamental border between where the sensor is and where the control unit is.

Other than that...
  • Apple lovers will be, no doubt, excited by this device and the promise of "Apple quality". Everyone else might have a doubt (for example, when they say "stainless steel", I ask "how thick?". Need to touch it to actually confirm this statement).
  • Needs to be installed where it has a constant (or at least frequent) view of you. And where are thermostats normally located? Correct, in the corridor, next to the air return. Good luck making the thermostat aware of you in a big house, or if it is located in a place you normally don't walk through often.
  • Remote control with no fuss means external server the thermostat is talking to. Keeping it secure requires you having the account at it, and sending *your* data to it. Oh, by the way, prepare to deal with it. This is the only way one can do it without the fuss. We're doing the same. So will everyone else.
  • Outside weather awareness means external sensor. Or always-on internet access and temperature resolution down to city or so. Which is pretty much useless to you.
  • Speaking of which, support site search... Let's just say it could be better.
  • Even though zoning support is advertised, it will be limited for one simple reason: zoning systems need much more granular signal than just on/off.
  • iPhone and iPad only? Again? Where's my Android app?


  • I want to buy this product on Newegg or Amazon. I don't want to engage in a process as complex as house refinancing, and be subjected to individual pricing based on how much I am apparently willing to cash out.
  • Did I forget to mention? I want to know the price up front.
  • A blog without an RSS or Atom feed? Is a clog.
  • Customer reviews for a product that is not being publicly sold? That's not a good smell in my book.
  • "Invitation only" procurement model suggests that not everything is as shiny as the outside ring of Nest thermostat, and it may not be as production ready as they want us to believe.
  • The knee-jerk reaction of my son to seeing the demo was: "One button? Again? I'm sick of one button!". Couldn't agree more. Two quotations come to mind immediately:


Their documentation is very good, and lots of unknowns have already been resolved. However, there are fundamental questions that are left unanswered:
  • The price for the device $249 plus shipping;
  • The price for Nest account;
  • What they do with your data;
  • Do they allow you to take it away (like others do);
  • Does the device and infrastructure support open protocols, or it is as closed as everything Apple ever did?
And if the account turns out to be free, but you can't take your data out? Then you are the product being sold.

UPDATE (2011/11/02): Price was published.
UPDATE (2011/12/06): BGR published a short review. Comments deliver.

Tuesday, September 13, 2011

Early Access: SwitchDamper

For years, DZ was able to control modulating dampers.

It seems, however, that bang-bang dampers still have their place, hence, SwitchDamper was added to Subversion and will become a part of the next release.

Now you can use DZ to control any HVAC actuator that is controlled by a switch. This includes, in particular, but not limited to:
  • existing open/close dampers normally controlled by 24VAC;
  • electric heaters that are configured as auxiliary heaters in a complex zoned system;
  • hydronic, geothermal and steam system valves.

Friday, March 11, 2011

DZ 3.6.4 Release Is Out

Changes since 3.6.3

  • Fixed the Yesterday bug;
  • Significantly improved JMX instrumentation and system configurability without restarts.

Friday, January 7, 2011

Open Letter to SeedStudio

A while ago I purhcased a couple of relay shields from your site and was recommending them to my project's users . Unfortunately, you discontinued the original product and no documentation, nor any forwarding or upgrade information, is available.

Even though a new version of the product now exists, it is not immediately obvious to my users whether the new product is compatible with the old, and whether it can be used as a drop-in replacement.

Other open hardware manufacturers retain documentation for even discontinued products available indefinitely (example here), because even though the product is discontinued, there are many instances of it in possession, and sometimes open source project maintainers need to support products that they don't have in their hands (such is my case).

It would be much appreciated if you could consider making the documentation for the old version available, and providing version compatibility notes on both old and new devices so people without deep technical knowledge could be sure that the new version of the product can be used instead of old. Including a link to a new device on old device's page won't hurt either.

Thank you for consideration,


PS: The text above was sent to you a few months ago, but there was no response. Since then, it came to my attention that not only relay shield was upgraded, but also the UartSB V2.2, and possibly others. The pattern is obvious - you're upgrading devices as soon as you run out of stock of components you could get for the cheapest price. That's OK, everyone has to make a living. However, if you respect people that make your bread and butter just a tiny little bit more, you might get more respect, which will definitely make your sales better. On the other hand, if you are an uncertainty, you are a risk. If you are a risk, you are a threat. Threating your customers is a bad business strategy.

For now, I will only recommend your products only if there is no other alternative, and a clear link to this post will be included next to recommendation. Your competitors' products will be recommended instead, even if the price is higher. Good luck.