HEAT is a mains-powered, microcontroller-based smart hot-plate designed for electronics work such as SMD soldering, thermal experiments, and controlled heating tasks. It integrates a fully assembled PCB, a high-power resistive heater, a temperature sensor, a fan, and an OLED UI into a compact, safe, and reliable system.

Why I Made It:

I wanted a precise, repeatable, and safe heating solution for small electronics projects. Conventional PID hot-plates often overshoot or are difficult to tune for small, fast-heating plates. By designing my own PCB and firmware, I could control heating and optimize the assembly for durability and ease of use.

How It Works:

Control Core: STM32F103C8T6 microcontroller running a Smart Pulse & Coast algorithm for temperature regulation.

Power Stage: Mains AC heater controlled through a zero-cross SSR (MOC3063M + BTA16 triac) to minimize electrical stress and EMI.

Temperature Feedback: 100 kΩ NTC thermistor measures plate temperature, with firmware averaging and filtering for smooth control.

Fan Cooling: 5 V DC fan driven via MOSFET and software PWM for active cooling during or after heating.

User Interface: SSD1306 OLED and three buttons allow monitoring and setting target temperature, heating cycles, and safety limits.

Assembly: The PCB integrates all components, including heater connections, AC protection (fuse, MOV), and grounding, making it fully ready for safe operation.

Key Features:

Fully assembled PCB optimized for reliable high-voltage and thermal operation.

Zero-cross SSR control ensures smooth, safe heater switching.(no emi)

Physics-aware Pulse & Coast algorithm provides precise temperature control without overshoot.

Compact and user-friendly design with OLED UI and tactile buttons.

Durable 3D-printed enclosure(from ASA) with optional embedded nuts for reinforced assembly.

Try the simulation of the SSR control in Falstad:

➡️ Interactive Circuit Simulation

➡️GitHub LINK for the repo