RTD temperature probe: Is there an alternative to MAX31865?

Projects General Guidance
1

Hello

I'm looking to create a system for monitoring up to 5 (two wire) RTD temperature probe for my charcoal using an ESP32 board. My concerne , the cost of the RTD interface modules, MAX31865. It add up rapidly, 10$ to 30$ CAD per module. Is there an alternative to these interface?

For sure I could pay less, but will have to wait nearly three month to receive them from China.

Any suggestion?

Martin

2

Why RTDs? What temperature range?

3

An RTD probe is just a temperature sensitive resistor.

You can use a simple voltage divider or a Wheatstone bridge to determine the resistance, and hence measure the temperature.

You need to take into account that the current through the RTD may cause it to heat up, distorting the reading, but that would not be a concern with a cooker.

4

groundFungus:
Why RTDs? What temperature range?

Hello GrounfFungus,
Planed temperature range from 75f to 500f
Why RTD, because these probe

  • are frequently used for food grade insertion thermometer.
  • Easely found with a metalic wire protection
  • Affordable
  • Wide range of temperature measurment
    I'm using a type k thermocouple for another charcoal temperature controler. I wanted to try working with another type of probe for the previous characteristic.

Excuse my English.
Martin

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