Hi this seems to be an often done project but im struggling to identify exactly what I need. I want to build a near-instant temperature probe for food - not really a barbecue/grill one, one i can use to check that food is at a safe temperature. A home made thermapen.
Esphome home supports this max6675 sensor which seems to be what i’m after, but they always have a threaded end, or a thick pencil shaped probe on the end.
is there a probe type i need to google for that works with a max6675 that has a pointed end?
or
Does that one in the picture, that has a 3.5mm connector on it, have any support in esphome? If I was to wire in a 3.5mm jack, is there any chance it would work with the max6675 board?
The backbone of most simple thermometers is resistance.
It gives a resistance depending on the temperature.
This can be easily read by ESP´s, the issue is the calibration.
The resistance is generally not linear and therefor the coding will be hard.
Some probes/thermometers has a (if I recall correctly) K-value which can be used in libraries to calibrate it easier.
You probably could import the library in ESP-Home, I don’t have the skills, but as far as I remember it’s possible.
Or you calibrate the thermometer to a temperature range you are likely to use it in and just don’t care that it’s slightly off in the other temperatures.
That looks like it is likely a “thermister” which won’t work with the MAX6675 converter board. That board expects a thermocouple which is usually what you find that have the rounded ends.
for that you will just use an ESP8266 NodeMCU and set up a voltage divider circuit to accurately measure the probe reading on the analog input pin (A0)
Here is a bunch of info from a smoker sensor that I put together.
Be ware that you will need to to know the base resistance value of the thermister. They are classified as something like 10K NTC, 100K NTC, 1M NTC. That value is based on resistance at room temp (70F).
the ones from the link are 10K probes (as far as I can remember)
Also since they don’t have any calibration values provided for them it’s a bit of a job to get good values so you can convert the usual curve into a linear temperature value.
if you need (want…) more detailed info I can try to help you out.
