Drying Monitoring System for Coffee Beans Based on IoT

The Drying Monitoring System for Coffee Beans Based on IoT operates by continuously tracking environmental and thermal conditions to optimize the post-harvest drying process. At the core of the system is the Arduino Uno R4 WiFi, which serves as the central processing unit. The DHT22 sensor measures ambient temperature and humidity surrounding the coffee beans, while the MLX90614 infrared thermometer provides non-contact surface temperature readings of the beans themselves. Powering the system requires a robust setup: an Omron 24V 5A power supply provides the primary high-voltage rail, which is stepped down via a DC-DC step-down converter to supply appropriate logic and lower-voltage requirements, while safely accommodating the heavy-duty demands of the 12V fan and Peltier module used for temperature and moisture regulation. The Arduino interfaces with a Monster Motor Shield (utilizing the VNH2SP30 driver chip) to control the high-current actuators like the 12V fan and Peltier module using Pulse Width Modulation (PWM). As the sensor data is gathered, the Arduino Uno R4 WiFi utilizes its onboard wireless capabilities and the PubSubClient/WiFiS3 libraries to package the telemetry into JSON format using ArduinoJson. This data is then transmitted via MQTT to the ThingsBoard Cloud platform, allowing operators to monitor drying metrics remotely and adjust environmental parameters in real time to prevent mold growth and preserve the flavor profiles of the coffee beans.