Andrew Morris was frustrated by the inadequate thermostats on most space heaters. The thermostat is typically built inside the heater and has little contact with the outside world. It switches on and off according to the temperature inside the heater, not the ambient air temperature. This makes it little more than a duty-cycle controller, similar to the nonthermostatic control on an electric stove or the temperature control on an electric blanket.
Morris decided to design an electronic thermostat that senses the actual room temperature. He tested and tweaked it to get the proper control range and hysteresis. The new thermostat has an internal adjustment to set the center temperature. It has a range of 20F, centered at 70F. In creating the new thermostat, he did not alter any of the safety functions in the heater.
Wall mounting is more convenient to use and gets a better sense of the room temperature.
Andrew Morris' gadget saves electricity by using the actual room temperature to control the heater.
Good point, Gafisher. Everybody in product development seems to be suing and getting sued these days -- Sony, Apple, MS, Amazon, Samsung. They all have one thing in common -- $$$. I don't believe the small inventor is going to get sued simply because there is no possibility of a big payday.
Getting sued? Magizines (hobby and professional) have been publishing plans for projects for well over a century. Can anyone name a single case where an author has suffered any civil or criminal judgment because someone attempted to replicate the published design and got into trouble?
Line voltage safety: We have been using electricity for well over 100 years. If anyone is doing electrical and electronic work and still doesn't know you can get a shock from line voltages, then he pretty much deserves to get zapped.
I am not an attorney but I am almost certain you won't get sued for giving this kind of information away. Otherwise hobby electronics magazines, who actually sell the information, would have long ago ceased to exist as they depend on people like you for their projects. They print stuff like this with a simple warning that high voltages are accessible so use your own "good judgement".
Take a look at the July 2012 projects issue of Elektor USA and you will find four or five line operated projects that are not transformer isolated, usually powered by a resistor/capacitor direct to the power line. And since these have to operate in Europe as well as the US, they expose as much as 230V.
IANAL either, but I'd say no liability for what someone does by their own choice.
The whole liability issue is fodder for another day, but I have to wonder how many inventions have been suppressed by their inventors over the simple fear that some idiot is going to barbeque himself while misusing the product. Would Edison, Ford, Bell have brought their ideas to market in today's litigious toxic atmosphere?
I like it, I could use something like this for my gazebo in the winter. Also, if anyone has not already said so, you can probably use a power switch tail from sparkfun. I used one to automatically switch off my soldering iron if it falls off of my workbench.
is available at Amazon for less than it would cost to make mine. It also has a digital readout. You can solve the temperature issue by setting its temperature a couple degrees cooler that you want the eye-level temperature to be. Just keep it well away from the heater. I don't want the liability of someone building a faulty version of my gadget.
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