ESP32 Coffee Roaster - MQTT-Only Version

A streamlined ESP32-based hardware controller for a modified popcorn popper coffee roaster. This version focuses on core roasting functionality with MQTT communication for external system integration.

Hardware Components

• ESP32 Development Board (NodeMCU-32S)
• 2x MAX6675 modules with K-type thermocouples for bean and environment temperature monitoring
• Solid State Relay (SSR) with PWM for heater control
• L298N motor driver with PWM for DC fan control
• Modified popcorn popper as roasting chamber base

Key Features

• MQTT-only communication - streamlined for integration with external systems
• PID temperature control with automatic and manual modes
• Real-time telemetry publishing at 1Hz
• Safety systems including fan failsafe and emergency stop
• OTA firmware updates for remote maintenance
• Persistent configuration stored in EEPROM

Communication Protocol

Uses MQTT for all external communication, eliminating Modbus TCP and web server dependencies. Designed for integration with:

• Bridge applications for Artisan compatibility
• Node-RED for visual programming
• Custom dashboard applications
• IoT monitoring systems

Recent Changes (MQTT Integration Branch)

• ✅ Removed: Modbus TCP server and AsyncTCP dependencies
• ✅ Removed: Built-in web server for simplified architecture
• ✅ Enhanced: MQTT communication with comprehensive telemetry
• ✅ Streamlined: Core control functions only
• ✅ Optimized: Reduced memory footprint and improved reliability