Accuracy of NTC Thermistor Measurements Using the Sensor to Microcontroller Direct Interface
Marco Grossi, M. Omaña · 2024
Portable and wearable sensor systems are usually based on microcontrollers or field programmable gate arrays (FPGAs), where the sensors are measured using an analog-to-digital converter (ADC).An alternative solution, with benefits in terms of cost reduction and lower power consumption, is the sensor-to-microcontroller direct interface (SMDI), a technique where the sensor is measured using the general purpose input output (GPIO) interface present on any microcontroller or FPGA.In this paper, the measurement accuracy of a non-linear temperature sensor (NTC 3950) using SMDI was evaluated by means of LTSpice simulations in the temperature range from -10 • C to 80 • C. The temperature was estimated using two different models and the results have shown that the most accurate model (Steinhart-Hart model) achieves an average temperature error of 0.078 • C.