I’m a big fan of the Thermostat. They’re clever, and all they want is for us to be comfortable.
Even the simplest mechanical ones are really little robots, whos only goal in life is to keep you comfortable. You tell them what you want the temperature to be, and they dutifully turn the furnace (or A/C) on and off all day and night so that your house remains in your comfort-zone.
The programmable ones of course take this to the next level – with a programmable, you don’t even have to tell the thermostat what your desired temperature is. Or rather, you tell it once, what temperatures you prefer throughout the day and the week, and from that point on, it keeps you comfortable. It’s like magic.
What else in the home works so hard to keep us comfortable, yet asks for nothing in return? The only thing that I can think of that comes close, is a chair or a sofa.
Despite all this, however, I’ve been starting to want more, from my thermostat…
The first seeds were planted several years ago. I saw a programmable thermostat that came with two remote controls. It was outrageously expensive, but there is an undeniable appeal to the thought of being able to crank up the heat without getting out of bed, on a cold winter night. The cost, however, was beyond my means at the time. And by the time I could afford it, that unit was no longer available.
Then last year, the local utility company sent out offers to get a thermostat that you could program over the internet. It sounded like a good idea, but at the time, I did not persue it. They sent the offer again this year however, so I did investigate.
Their unit is a normal programmable thermostat, that has an RF receiver in it – basically a numeric pager unit. This allows one-way communication, so you can send commands to the unit but not retrieve any information. It’s free, but you have to give up some control: they’ll give it to you, if you agree to let them turn off your air conditioner if the demands on the power grid are too high.
Still, it looked hackable so I filled out the application. They never got back to me; I figure its because I use so little power that they’d never recoup their costs of giving it to me.
Finally, last week I spotted a thermostat at Canadian Tire that came with a remote control. It wasn’t too costly so I grabbed it, with the intent of hacking it. It was a Noma model, which I think is CT’s house brand? Whatever. Let’s look inside!
- Noma Thermostat
- Front of PCB
- Back of PCB
- RF Mount
- RF Module
Aside from the generally poor construction, here’s some things to note: The unit uses RF communications, at the 915MHz band. Comms are one way only, with data going from the remote to the base. This allows the base to display the temperature info from wherever the remote is, but the remote cannot display the temperature, mode, current function, or anything else, from the base. The remote allows you to override the base to a maximum of +/- 6 degF (3degC). Finally, both the remote and the base use a cheap thermistor to determine temperature.
So, it’s not perfect. The one-way comms is a real limitation I think. An additional pisser is that you can easily hack into the comms on the base (since the RF is on a daugher board) but on the remote, it would be much harder as none of the communication lines are accessable (damn those black blobs.) So anything you hack in, is easiest to add at the base, meaning you lose the remote aspect – or have to roll your own remote anyways.
Indeed, when I tried to use it as it was intended, it didn’t really work well anyways. It’s a novelty, but not really a very good thermostat. Verdict: Fail.
So what is it that I really want?
Putting together all the various ideas, I want a thermostat that is programmable and runs fine as a stand-alone unit. I also want it to be able to be accessable via remote control, but with two-way communications, so that a remote unit can at least display everything that the base unit can display, plus the remote should be able to alter the temp, maybe switch modes to hold / run, that sort of thing. Finally, it would be really nifty if it could be wired into my home network, so I could access the data and control through my computer, laptop, iPhone, etc.
The solution, then, is to build my own thermostat, from scratch!
Stay tuned, this story is not over.