Maintaining proper environmental conditions is critical in cold chain systems used for storing and transporting temperature-sensitive products such as vaccines, medicines, and perishable foods. This project presents an IoT-based Cold Chain Monitoring System that continuously monitors temperature, humidity, and door status using an ESP32 microcontroller integrated with multiple sensors and cloud connectivity. The system uses two DS18B20 temperature sensors to measure temperatures at two different levels inside the refrigerator to ensure uniform cooling conditions. A DHT22 sensor is employed to monitor the humidity level within the storage environment. Additionally, a reed switch is used to detect the opening and closing of the refrigerator door, which helps identify potential temperature fluctuations caused by frequent access. All sensor data are processed by the ESP32 and displayed locally on an LCD display using the I2C interface for real-time monitoring. The collected data are also stored in an MMC memory card for offline record keeping and historical analysis. Simultaneously, the ESP32 transmits the data to the ThingSpeak cloud platform via Wi-Fi, enabling remote monitoring and visualization of environmental parameters over the internet. To enhance system reliability, a buzzer alert mechanism is implemented. When the temperature or humidity exceeds predefined safe limits, or when abnormal conditions occur, the buzzer is activated to provide an immediate warning. This allows quick corrective action to prevent damage to stored products. The proposed system offers a low-cost, real-time, and reliable monitoring solution for cold chain applications. By combining local display, cloud monitoring, and data logging, the system improves traceability, safety, and management of temperature-sensitive goods.      

Objectives of the Project:  

1. To design and develop an IoT-based cold chain monitoring system using an ESP32 microcontroller for real-time environmental monitoring.
2. To measure temperature at two different levels inside the refrigerator using two DS18B20 temperature sensors to ensure uniform cooling conditions.
3. To monitor the humidity level inside the storage environment using a DHT22 sensor.
4. To detect the open and close status of the refrigerator door using a reed switch in order to identify possible temperature fluctuations.
5. To display the real-time sensor data (temperature, humidity, and door status) on an LCD display using an I2C interface for local monitoring.
6. To store the collected sensor data in an MMC (memory) card for offline record keeping and future analysis.
7. To transmit the environmental data to the ThingSpeak cloud platform through Wi-Fi for remote monitoring and visualization.
8. To provide abnormal condition alerts using a buzzer when temperature or humidity exceeds predefined threshold limits.
9. To ensure continuous monitoring, data logging, and improved safety for temperature-sensitive products such as vaccines, medicines, and perishable foods in cold chain systems.

        Components Used:

• Regulated Power Supply.
• ESP32 Microcontroller.
• DHT22 sensor
• TWO DS18B20 Temperature sensors.
• Read switch.
• MMC card.
• Buzzer.
• LCD display.

        Software’s used:  

1. Embedded C programming.
2. Arduino IDE for dumping code into Micro controller.
3. Express SCH for Circuit design.
4. Thingspeak API.

      Regulated Power supply:

           

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