Replacement Thermo Probe?

[walking dude]

yeah...........wish they would of gaven ME the wireless.........but can't complain...........

 

[sgtgeo]

I work in a lab and we have lots of instruments that have to have very accurately regulated temperatures.

We use type J and K thermocouples of various lengths and diameters. These are quite robust and last for a long time even in 1000*F high moisture highly acidic enviorments.

I am curious why no kitchen type thermometers use these readily available probes.

You can get a lab grade thermocouple reader but they are usually expensive.

I am considering this route for my PID smoker control system I'm working on

 

[geek with fire]

I've spent the last year and a half playing with temperature control processes and temperature probes for cookers. The reason why companies don't use thermocouples is that they are too darned expensive. Thermistors can be bought with pennies. Thermocouples normally have platnum in them so even the cheapest made thermocouples are still expensive.

The next reason is the controllers. The cheap oven probes that use thermistors don't require much on the electronics side; they're basically just ohmeters that convert resistance to temperature. Just like the probes, thermocouple controllers are more complex and therefore are more expensive.

If you are bent on useing thermocouples though, thermoworks has a pretty decent thermocouple controller for less than $45.
http://www.thermoworks.com/products/handheld/mtc.html
I use their plug type thermapen and am very happy.

I also use Phidgets USB thermocouple controllers to connect to my control system on my laptop.

Keep us updated on you PID controller project.

 

[sgtgeo]

I'm collecting the parts now to use a PID controller to regulate the heater output based on a thermocouple reading. Planning on building it into a small control box that will contain the PID controller, relay, relay heatsink and all the wiring.

If i can find a dual zone PID I could also have it turn off power at a given meat temp. So far I have not been able to find an inexpensive 2 zone controller

Should be an interesting exercise in control theory

 

[geek with fire]

There was a thread sometime back about a cheap China import PID controller. You might do a search for that.