The combination of low power consumption, high sensitivity and signal stability makes NTC thermistors the most popular temperature sensor choice in automotive battery management, motor and climate control as well as factory automation and field instruments. In this application note the basic circuit design considerations will be explained to convert the NTC’s resistance change into a digital temperature readout. The circuit example uses an ADS1115 from TI to convert the voltage drop of a K560 surface sensor to a 16 bit I2C output for skin temperature sensing. Alternative resistance to temperature calculations will be compared: Exponential curves, lookup tables and Steinhart Hart equation. For all cases Python 3 code is available for download that can be adapted for other applications and other NTC curves in own projects using Python 3 or CircuitPython.