Refrigerator Temperature Monitoring

Motivation

Keeping food fresh isn’t just about taste—it’s about safety. In Japan, food sanitation law even requires strict temperature control.

So, I built an IoT-based automated monitoring system using M5Stack to make refrigerator management smarter and stress-free.

Features

To keep the system simple, I avoided complex operations and focused on ease of use.

Multiple M5Stack devices can be operated simultaneously, and all recorded temperature data is collected into a single database.

This design is especially useful for restaurants, where multiple refrigerators are often in use.

The system automatically logs temperature data into a database at regular intervals—even when the restaurant is closed and unattended.

The M5Stack display shows the following information:

• WiFi connection status
• NTP connection status
• Database connection status
• Current date and time
• Timestamp of the last recorded data in the database
• Current temperature

From a web page, you can view records, generate graphs, or export CSV files.

Note: The data shown in the images was recorded at room temperature during testing.

If the temperature goes above the safe range, or if the system detects an error, instant alerts are sent via email and SMS.

Implementation

A working prototype has already been tested at home, proving the idea is both practical and reliable.