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Topic: DIY High temp thermistor probe (Read 3 times) previous topic - next topic


I've been toying around with the idea of creating a temperature control unit for a bullet style barbecue smoker using an Arduino, a thermistor and some 5v fans. The idea is to make something similar to what they sell at pitmasteriq.com and other places, only cheaper. Due to the cost constraints I'd like to use a thermistor instead of a thermocouple. I can't find any reasonably priced thermistor probes that will get me into the 2-300 degrees C range. My question is this: is it possible to buy a glass bead thermistor and enclose it in copper tubing and still get an accurate reading? The thermistor I have in mind is Digi-Key Part Number 495-2135-ND and I'm thinking of encasing it in either a plumbing stub out, or some kind of copper pipe with one end braised or pinched shut and then filled with a high temperature silicone sealant. The environment that the probe will be in is likely to never be much above 200* C, but it will be quite humid. Is this possible?


You have the problem of how to attach the wires to the thermister - solder won't work at 300C.
[ I won't respond to messages, use the forum please ]


My thought on the joint was to use a lineman's splice or something similar, and let the filler in the probe body help keep the joint from moving too much. Sounds great in theory but how it would hold up in practice is another story. If the question of solder can be solved, is the rest of the idea plausible?


Thermocouple too expensive ? Come again...

// Per.


Thermocouples themselves aren't the cost issue. Finding them cheap isn't difficult. It's the roughly $18USD amplifier setup that's the cost issue.

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