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Hardware hacking an electric fan heater without burning the house down

BigG

I recently purchased a 2kW electric fan heater for $12 (it was on sale). This was an offer too good to refuse, especially as the latest Project14 competition is hardware hacking.

 

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These fan heaters, like any other personal heater, are great for the winter months.

 

However, as I have on the very odd occasion left an oil heater on over night (it is very easily done), I certainly wouldn't want to do the same with an electric fan heater.

 

So I want to add in some "smarts" or electronics to ensure that it can automatically turn off if I leave the room etc. and it would also be handy to remotely adjust heat and fan speed.

 

The nice thing about this particular fan heater is that it has a safety cut off switch, should it tip over. I thought that this would be my starting point for my project, as this part can be readily enhanced.

 

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The part I am struggling with is how to or what electronic options could I use to hack the heater settings switch, which is mechanical. How could I do this electronically, bearing in mind we are dealing with mains voltage.

 

{gallery:autoplay=false} Heater Settings Switch

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And the other question is what options are out there on how to hack the fan speed controller... this also is mains voltage, so I'm out of my depth in terms of using a digital potentiometer, for example.

 

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Any suggestions / ideas would be greatly appreciated.

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  • The awesome thing about element14 is the wealth of expertise and the documented lessons learnt... Automatic Dough Shaper - Blog #10 More Magic Smoke

     

    Yes, I'm exploring triacs! Thankfully, I've ticked that off the list - i.e. know your power ratings etc. So I basically just want to use one triac for now to remotely turn the device on and off. I decided to place the triac above the microswitch as shown (will be snipping that red wire).

     

    image

     

    That's the plan anyway. I'm working through element14 as there are plenty links on triacs.

     

    Now when looking at my design process, I've zoomed straight onto snubber capacitors (I have a habit of doing that... zoning in on something that's probably not necessary but just want to understand).

     

    And, while searching online I came across these guys. They are reasonable price wise but are they appropriate... and if so, how do you choose.

    http://www.capacitorguide.com/mica-capacitor/

     

    Not sure what other bells and whistles are needed to look after the triac and the circuit for switching high loads. I'm basing my max load off 24A RMS (to cover the 6A + 16A).

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  • The awesome thing about element14 is the wealth of expertise and the documented lessons learnt... Automatic Dough Shaper - Blog #10 More Magic Smoke

     

    Yes, I'm exploring triacs! Thankfully, I've ticked that off the list - i.e. know your power ratings etc. So I basically just want to use one triac for now to remotely turn the device on and off. I decided to place the triac above the microswitch as shown (will be snipping that red wire).

     

    image

     

    That's the plan anyway. I'm working through element14 as there are plenty links on triacs.

     

    Now when looking at my design process, I've zoomed straight onto snubber capacitors (I have a habit of doing that... zoning in on something that's probably not necessary but just want to understand).

     

    And, while searching online I came across these guys. They are reasonable price wise but are they appropriate... and if so, how do you choose.

    http://www.capacitorguide.com/mica-capacitor/

     

    Not sure what other bells and whistles are needed to look after the triac and the circuit for switching high loads. I'm basing my max load off 24A RMS (to cover the 6A + 16A).

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