​Abstract: Temperature sensing is fundamental in various engineering applications, including industrial automation, HVAC systems, and biomedical instrumentation. Accurate temperature measurement requires signal-conditioning circuits to process the low-level, often nonlinear outputs of different types of temperature sensors. Traditional designs typically require manual wiring and predefined circuits for each sensor type, limiting flexibility and increasing complexity. This article presents the design and implementation of an integrated smart signal conditioning circuit based on a microcontroller. The system autonomously identifies the type of connected temperature sensor whether it is an NTC, PTC, RTD, or thermocouple by analyzing its resistance value and surrounding temperature. Once identified, the system automatically routes the sensor to the appropriate analog signal-conditioning path. Thermocouple signals are amplified using an AD620 instrumentation amplifier (gain ≈ 207.5) before analog-to-digital conversion, while RTD measurements are acquired through a precision voltage-divider interface and processed using a linear temperature-resistance model. This hybrid analog–digital architecture enables flexible multi-sensor integration without relying on dedicated digital converter modules. The proposed system significantly reduces the need for manual sensor configuration and wiring, allowing for adaptive interfacing and real-time measurement. Experimental validation and simulation (Proteus) demonstrate the reliability and accuracy of the system under various conditions. This work paves the way for intelligent, reconfigurable temperature sensing interfaces suited for future Internet of Things (IoT) and industrial applications.

Keywords: Microcontroller, Temperature sensor, Signal conditioning.

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