I often forget to turn my central heating down when I leave the house, so I thought it would be cool to make a device that could do it for me and to have a website where I can check and change the heating. I was thinking about using the Arduino with an Ethernet shield for this. Programming won't really be a problem. I am however totally new to motors, and I have no clue as to which kind of motor would be suitable for this. This is the knob:
The idea is to have a motor sit next to it and attach four arms to it that fit in the corners of the knob. I'll also add a potentiometer to be able to control it when I'm home.
So, is this possible? Thanks!
Edit:
So I understand this is not the best solution and that it would be better to hack a thermostat or use an electric valve, but unfortunately both of those things are not an option for me. I have just one radiator (this one) and that's it. So I'd still like to know what kind of motor would be suitable for this. I was thinking a servo would be good but that limits me to 180 degrees of rotation, and I need a little bit less than 360. There are ways to get more than 180 degrees, but that would remove the position feedback thingy. Do I even need that?
Best Answer
I once visited a hackerspace that was trying to make a light bulb throb between bright and dim for a replica TARDIS. Their solution was to get an ordinary dimmer, such as you'd mount in your wall, then mechanically link this to an RC hobby servo controlled by an Arduino.
It worked, for a few hours. Then something would break, every time.
Then, I showed them how to put a triac on an ATtiny. Not only was this solution about three orders of magnitude cheaper, it never broke.
Here's the lesson: just because you do something with your hands doesn't mean a machine should. This is why industrial automation robots look like this:
and not like this:
There are machines designed to control the flow of heated water to your radiator, and they don't look like hands to grab the knob that's already there. By searching for "electric radiator valve", I found this, available from decorisland.com:
It looks like the interface is two wires, and you apply a voltage to open the valve. This should be pretty easy to interface with an Arduino. But, it's also probably compatible with a standard wall-mount thermostat. You could even get one of the many internet enabled thermostats on the market (such as by Honeywell or Nest) and skip the Arduino, avoiding this problem: