Feature/thermistor

[finger563]

Description

• Added thermistor component with example for NTC
• Updated and rebuilt docs
• Updated CI

Motivation and Context

Thermistors (temperature sensitive resistors) are cheap, common, and useful tools for measuring the temperature of the circuit or its surroundings. Conversion from the measured voltage across the resistor to the actual temperature requires the implementation of the Steinhart-Hart equation to compute the temperature as a function of the log of the measured resistance proportional to the nominal resistance. This requires the use of a ln() function (for which we already have a fast_ln() implementation in the math component) as well as storing some information about the thermistor and the circuit it is in (such as the voltage divider configuration, supply voltage, nominal resistance, fixed resistance, and beta value). This component / class stores those information in a way that makes it much easier / cleaner to measure the temperature using a thermistor.

How has this been tested?

Running the new example on an TinyPico (ESP32) board. I don't have an NTC on hand, so the main part of the example that tests is the comparison to the manually entered table from the datasheet. To check our calculated temperature vs. the datasheet.

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Note: I didn't have an NTC to connect to the ADC, so it's not able to read actual temperature in the screenshot below.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Hardware (schematic, board, system design) change
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• I have updated the .github/workflows/build.yml file to add my new test to the automated cloud build github action.
• All new and existing tests passed.
• My code follows the code style of this project.