Development of A Smart Food Warmer with Real-Time Temperature and Humidity Monitoring

Abstract

Conventional food warmers often offer limited environmental control, leading to food overheating, severe dehydration, quality degradation, and excessive energy consumption. Objective: To address these limitations, this study developed and evaluated a portable smart food warmer that automatically regulates internal temperature and relative humidity using an ESP32 microcontroller and a DHT22 sensor. Method: The closed-loop prototype was developed using the Engineering Design Process and integrated a 20×4 liquid crystal display, an incandescent bulb, a circulation fan, a humidifier module, and a manual humidity bypass switch. Results: Experimental evaluations demonstrated that the hysteresis control loop successfully maintained temperature stability within the target 55–60°C range, limiting thermal fluctuations to ±1.0-±1.5°C. The selected 300 W incandescent bulb achieved the target holding temperature of 60°C in 1 minute 15 seconds. At the same time, the humidity subsystem successfully regulated the chamber's relative humidity between 50% and 75%, with a moisture recovery time of 4 minutes 10 seconds. Energy consumption across ten tested heating-element wattages was highly comparable, ranging from 0.00567 to 0.00700 kWh per heating cycle, with the 300 W configuration consuming 0.00625 kWh. Conclusion: The findings confirm that integrating embedded systems and automated control can significantly improve food warming performance, offering a practical, reliable, and cost-effective solution that preserves food quality, protects public health, and enhances energy efficiency in real-world applications.