I haven’t removed it yet because I want to make sure it’s feasible before breaking something. I imagine the knob connects to a standard potentiometer, but I’m not sure. Do I have to measure the contact point with a multimeter or similar tool? I’m totally new to this, so sorry for the naive question. Eventually I’d like to control this using an Arduino + temperature sensors + a machine learning Algorithm. This part seems easier.
If the heater is electric, then the control is often a bi-metal thermostat switch that controls the power to the heater. If this is the case, then it is not a simple potentiometer. If you were to replace this, you would need an electronic switch that could handle the voltage and current. Perhaps not trivial.
If you rotate the knob, can you at some point here a faint click? Does that position change based on the temperature of the room? If so, it is a bi-metal switch.
Thanks for your reply. The position doesn’t change when the knob is turned and there isn’t a click. I was able to find the exact model online. Here is a link:
In English this is a heater (convecting device) with electronic regulation. I would therefore assume that the dial is probably a simple potentiometer feeding an electronic circuit that monitors the temperature and turns on and off the power to the heater. That circuit could be a micro, or old fashioned analog circuitry.
If it is indeed a simple pot, then you have a few possibilities. First is to replace it with a digital pot and control that with your micro. Or you could learn what the voltage levels are for the output and generate them with a DAC. But before you could decide you would need to look at the voltages on the pot, the type of power (AC/DC) and the current flowing through the pot. I would assume the current was DC and fairly low levels that could be handled by a digital pot. But the voltage levels may be too high is the circuity is analog.
Some reverse engineering would be needed. Do you have a multimeter and or an oscilloscope?
Man. You’re awesome. Thanks for the great reply. I’m buying a multimeter when I get back to the U.S. this December to visit my parents. It’s cheaper there. Everything’s a bit expensive in France. These heaters are pretty cheap, so I’m not as worried as I was to break it by accident. A friend suggested building a relay controlled by an Arduino to avoid destroying the heater. It seems like a good idea. I’m going to try your solution first because it seems more elegant.
Thanks again for the great responses. I’ll post what I end up doing.
Don’t tell your fire insurance underwrite about this hack.
The old X10 system used to fake the thermostat by creating a very small/localized (like 2W or some such) heat source that affects the sensor in the thermostat (for the heater). Heat source on causes heater to shut off, and vice-versa. No wires to raise UL risks. Heat source can be a small resistive wire that radiates small amount of heat that rises up to enter the thermostat area where its sensor is. That resistive wire could be low voltage for safety reasons.
You might want to look on the web for the old X10 gizmo that did this - years ago. Probably still some around. Maybe ask on the Homeseer.com forum.
