Week 12 - Alejandro Reyes - Fab Academy documentation

Final Project

Anxiety-monitoring wearable bracelet

Main Hardware

ESP32-C6, MAX30102, vibration motor, LED and battery

Main Goal

Integrate all subsystems into a functional prototype

Assignment

Design and document the system integration for your final project.

System Integration

During this week I focused on defining how all the systems developed throughout Fab Academy will be integrated into my final project.

My final project is an anxiety-monitoring wearable bracelet capable of measuring heart rate using a MAX30102 sensor connected to an ESP32-C6. To transform the previous prototypes into a complete wearable device, I needed to integrate electronics, programming, textile fabrication and mechanical design into a single system.

System integration overview — Overview of all the subsystems that will be integrated into the final project.

Integration Workflow

Battery Integration

Make the bracelet fully portable.

Flexible PCB

Adapt the electronics to the wrist.

Firmware

Improve heart rate analysis and filtering.

Textile Cover

Protect and hide the electronics.

Embroidery

Add the anchor logo to the bracelet.

Fastening System

Create an adjustable wearable mechanism.

Electronics Integration

The first subsystem I integrated was the electronics. Based on the work completed during Week 10: Output Devices, I added a battery so the bracelet can operate independently without requiring the ESP32-C6 to remain connected to a computer.

This is an important step because it transforms the prototype into a truly portable wearable device.

The battery system will allow future testing to be performed under real-world conditions instead of relying on a USB connection.

Battery integration for portable operation.

Flexible PCB Development

After defining the power system, I focused on developing the flexible PCB.

For this stage I used the PCB developed during Week 10 as a starting point and applied the vinyl cutting techniques learned during Week 2 .

The objective is to replace the rigid PCB with a flexible circuit that can adapt to the shape of the wrist while maintaining all the required electrical connections.

Firmware Integration

Once the flexible PCB is assembled and functional, I will continue improving the firmware developed during Week 10 and Week 11 .

The goal is to calculate the user's average resting heart rate, detect significant increases that may indicate anxiety, and filter noise caused by movement, ambient light or sensor artifacts.

Another important feature is allowing the user to indicate when they start exercising. Since physical activity naturally increases heart rate, those measurements should not be interpreted as anxiety events by the system.

Firmware integration — Heart rate processing and filtering workflow.

Textile Integration

After completing the electronics and firmware, I focused on the external appearance of the bracelet.

Using the laser cutting workflow learned during Week 3 , I will cut the fabric pieces that will cover the electronics while leaving an opening for the MAX30102 sensor.

This approach allows the electronics to remain hidden while maintaining proper sensor contact with the user's skin.

Laser cut fabric — Laser-cut textile components for the wearable enclosure.

Embroidery Integration

To improve the aesthetic appearance of the wearable, I will use the embroidery workflow developed during Week 16 and stitch the anchor logo onto the fabric.

Once the embroidery is completed, the textile layers will be sewn together around the electronics, creating a protective enclosure for the flexible PCB.

Mechanical Integration

The final mechanical subsystem will be developed using the skills acquired during Week 5 .

I will design and 3D print an adjustable fastening mechanism that allows the bracelet to fit different wrist sizes comfortably.

This fastening system will complete the wearable structure and improve usability for future testing.

Final Validation

Finally, I will test the complete integrated system to verify that all subsystems work together correctly.

This includes validating the electronics, flexible PCB, firmware, textile enclosure and fastening mechanism to ensure the bracelet functions as intended.

Successfully completing this stage will result in the first fully integrated version of my anxiety-monitoring wearable bracelet and will provide the foundation for the final project presentation.

Final prototype — Expected fully integrated wearable prototype.

Week 15: System Integration