SensWear: An Open Modular Wearable Platform

What is this project about?

SensWear is an open, modular wearable hardware platform designed for researchers, developers, and makers who want direct access to raw sensor data and full control over the stack.

Most commercial wearables are closed systems. You get processed metrics, limited APIs, and almost no hardware-level flexibility. We take the opposite approach:

• Fully open-source under MIT license
• Mainboard with BLE connectivity, IMU, and daughter board interface
• Interchangeable and customizable daughter boards
• Flexible PCB options for different body placements
• Full access to raw data (PPG, IMU, touch, etc.)

Why did I decide to build it?

As an AI/ML researcher working on wireless sensing and embedded intelligence, I repeatedly faced the same problem during my PhD studies and after:

I needed high-quality multimodal physiological data, but existing wearables were either closed, fixed form-factors, not designed for experimentation, or do not have the sensor modality I have in mind.

Instead of hacking around commercial devices, I decided to design a platform from scratch that:

• Is open by design
• Is small enough to be wearable
• Can support different sensor modalities
• Can evolve into different form factors (ring, wrist, patch)

System Walkthrough (Video)

Below is a short hands-on walkthrough of SensWear in action. In this video, I demonstrate:

• Swapping and chaining daughter boards
• Real-time BLE streaming of raw sensor data
• PPG and IMU signals reacting live
• Triggering feedback via LED
• How the modular interface behaves during reconfiguration

The goal is to show that this isn’t just a concept or CAD render, it’s a working, reconfigurable platform designed for experimentation.

How does it work?

SensWear is designed around a simple principle: decouple embodiment, sensing, and learning so you can experiment freely without redesigning everything each time.

At the core is a compact main board that integrates:

• nRF54L15 MCU + BLE for processing and wireless streaming
• BHI360 6D IMU for motion sensing and embedded sensor fusion
• Power management (buck converter, charger, fuel gauge)
• EEPROM for logging

Sensing and actuation are not hardwired into the board. Instead, they are implemented as interchangeable daughter boards connected via standardized board-to-board connectors (D2M interface).

Key technical details:

• Shared I2C bus for scalable multi-sensor integration
• Programmable daughter-board voltage (1.2V–5.5V) via TPSM83102
• Interrupt-capable GPIO lines for event-driven operation
• Optional daughter-to-daughter (D2D) chaining

Currently supported modules include:

• MAX30101 PPG
• MAX30208 temperature
• MTCH6102 touch
• DRV2605 haptic
• LP5562 LED driver

Because of this structure, adding a new sensor does not require redesigning the whole platform.

What I’m looking for

This is why I’m sharing it here. I’m looking for:

• Feedback on the hardware architecture
• Feedback on the overall idea. If it is useful and what kind of directions we can take SensWear to.
• Suggestions for additional sensor modules

SensWear is still evolving. The goal is not perfection, but iteration in the open.