ThermiGuard — NTC Thermistor Over-Temperature Alarm

About this project

ThermiGuard is a standalone over-temperature alarm system that uses an NTC (Negative Temperature Coefficient) thermistor and Arduino's ADC to measure ambient temperature without any digital sensor IC. The thermistor forms a voltage divider with a fixed 10kΩ resistor; the Arduino samples this voltage and applies the simplified Steinhart-Hart Beta equation to convert resistance into Celsius. When temperature exceeds a configurable alarm threshold, a 5V relay activates (to drive an external fan or alarm), a piezo buzzer pulses, and the red LED lights. A 16×2 I2C LCD displays live temperature and system status. This project teaches analog resistive sensing, voltage dividers, thermistor mathematics, relay switching, and hysteresis control — all core Electronics Engineering fundamentals.

What you get

• Complete, commented source code
• Full components list with quantities
• Pin-by-pin wiring guide and connection table
• Step-by-step upload and testing guide
• Project report (.docx, IEEE style)
• Presentation slides (.pptx)