Block Diagram

Final Block Diagram

Here is the updated and finalized block diagram for the Internet Communication Subsystem:

Design Explanation

This updated block diagram represents the finalized design of the Internet Communication Subsystem, incorporating all feedback and refinements made throughout the project development cycle.

Key updates include: - Updated GPIO connections: GPIO 35, 38, 43, and 44 are now designated for serial and digital communications between the ESP32 and other headers. - Simplified wiring structure with better separation of upstream and downstream communication. - Clearer labeling of power flow from the 9V barrel jack, through a 3.3V switching regulator, and into the ESP32 WiFi module.

Decision-Making Process

Our goal from the start was to establish a stable and efficient wireless communication pipeline between the environmental sensor subsystems and an external MQTT server/GitHub-hosted dashboard.

The ESP32-S3-WROOM-1-N4 was selected for its low-power wireless connectivity, integration ease, and support for MQTT protocol. GPIOs were chosen based on their digital I/O functionality and UART compatibility, and adjusted after prototype testing for best performance.

We used a 3.3V switching regulator to safely convert the 9V barrel jack input to a level suitable for the ESP32. The use of jumpers and headers ensures modularity and ease of debugging during subsystem integration.

Product Requirement Alignment

This design satisfies the Internet Communication Subsystem’s functional and electrical requirements: - Wi-Fi-enabled MQTT publishing of sensor data to a cloud server or GitHub-hosted website. - Reliable UART and GPIO-based communication with both upstream and downstream subsystems. - Regulated power delivery using a dedicated voltage regulator. - Scalable and modular system design using upstream/downstream headers to support other student-designed subsystems.

This final version is optimized for both functionality and maintainability in real-world classroom and demo environments.