#sensor

NTC-thermistor sensor maths as an API, computed locally and deterministically. The steinhart-hart endpoint converts between resistance and temperature using the Steinhart-Hart equation, 1/T = A + B·ln R + C·(ln R)³ — the most accurate NTC model — in both directions, solving the resistance at a given temperature with Cardano's cubic formula. The beta endpoint uses the simpler two-point Beta model, 1/T = 1/T0 + (1/β)·ln(R/R0) and R = R0·exp(β·(1/T − 1/T0)), to convert resistance to temperature or back from a reference resistance R0 at T0 (default 25 °C) and the beta coefficient. The divider endpoint recovers the thermistor's resistance from a voltage-divider reading — low-side R = Rs·Vout/(Vsupply − Vout) or high-side — so an ADC voltage can be turned into a resistance and then a temperature. Resistance is in ohms, temperature in °C (kelvin also returned), voltages in volts and beta in kelvin. Everything is computed locally and deterministically, so it is instant and private. Ideal for embedded, IoT, HVAC-control, 3D-printer and battery-management app developers, temperature-sensing and calibration tools, and electronics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is NTC thermistor conversion; for a generic resistive divider use an LED-resistor or voltage-drop API and for thermal expansion a thermal-expansion API.

api.oanor.com/thermistor-api