The problem
Food businesses and pharmacies are required by HACCP regulation to continuously log temperature and humidity in refrigeration and storage units. Manual paper logs are error-prone, difficult to audit, and offer no early warning when conditions drift out of range.
What we built
We designed a compact wireless sensor node around the ESP32-C6, chosen for its native Wi-Fi 6 and low power consumption. The device uses a one-button provisioning flow to join the facility's network, then reports readings every two minutes over HTTPS with API-key authentication.
Deep sleep between measurements keeps average current draw under 18 µA, giving the 1200 mAh cell a battery life exceeding 18 months under normal operating conditions.
The backend is a .NET 8 service backed by PostgreSQL. Incoming readings are stored with timestamp, device ID, and location. Threshold violations trigger push notifications and email alerts within 30 seconds of detection. An audit log meets the retention requirements of Serbian and EU food safety legislation.
The Angular web application gives managers a real-time dashboard with per-sensor graphs, alert history, device status and a PDF export for regulatory inspections.
Outcome
Deployed across multiple food businesses and pharmacies. The platform monitors devices across several locations and has generated zero false-negative alerts in field operation.