3-Wire Thermal Resistor Sensor Module – Temperature Detection Switch with High Sensitivity

Description

The 3-Wire NTC Thermal Resistor Sensor Module is a compact, low-cost temperature detection board designed for environment temperature monitoring and threshold-based control applications. It uses an NTC (Negative Temperature Coefficient) thermistor as the sensing element: as ambient temperature rises, the thermistor’s resistance decreases, changing the voltage at the comparator input. An onboard LM393 comparator compares this voltage against a reference set by a potentiometer, producing a clean digital output (HIGH/LOW) when the temperature crosses the user-defined threshold.

The module operates from 3.3V to 5V, making it directly compatible with Arduino, ESP32, and most microcontroller platforms. The digital output (DO) can connect directly to a GPIO pin, and the onboard potentiometer allows adjustable temperature threshold setting across a typical detection range of 20°C to 80°C. Power and output indicator LEDs simplify calibration and troubleshooting. This module is well-suited for individual makers building temperature alarms, fan controllers, or thermostat prototypes, and for business purchasers seeking a cost-effective threshold detection solution for light commercial applications.

Important limitation: This module is designed for relative temperature threshold detection, not precision absolute temperature measurement. For calibrated temperature readings, a digital sensor (such as DS18B20 or LM35) is more appropriate.

Features

• NTC Thermistor Sensing Element: Resistance decreases with rising temperature, providing good sensitivity to ambient temperature changes.

• LM393 Comparator Output: Clean, stable digital signal with strong driving capability (>15mA), suitable for direct microcontroller connection or relay module driving.

• Adjustable Temperature Threshold: Onboard potentiometer allows the detection trigger point to be set within the 20–80°C range.

• Wide Operating Voltage (3.3V–5V): Compatible with both 3.3V and 5V logic systems.

• Digital Switch Output (DO): Provides simple HIGH/LOW signal when temperature crosses the set threshold.

• Power and Output Indicator LEDs: Visual feedback for power status and digital trigger state.

• Compact PCB with Mounting Holes: Approx. 32×14mm board with fixed bolt holes for easy installation.

• Low Cost and Simple: Ideal for beginners, educational projects, and proof-of-concept temperature control systems.

Technical Specifications