Project description
My project consist on the development of a Wearable device that monitors movement quality, to focus on the detection of early changes in motor control that are associated with mucular disftrophy with a system that analyzes motion pattern to identify the variability, smoothness and range, that serve as indicaions of functional deterioration
Project Concept & Design Sketch
The design of the wearable device focuses on ergonomics and portability, as it is intended for long-term monitoring of patients with neuromuscular conditions. The system is conceived as a modular bracelet located on the wrist or forearm, a strategic position to capture the most significant data regarding arm tremors, range of motion, and movement smoothness.
As illustrated in the conceptual sketch, the device integrates an Inertial Measurement Unit (IMU) containing an accelerometer and a gyroscope. This sensor captures raw data of acceleration, angular velocity, and time, which are then processed through the onboard firmware. The signal processing layer focuses on three main pillars: calculating the Range of Motion, analyzing Movement Variability, and measuring Movement Smoothness through jerk analysis.
The system is designed to be highly functional and user-centric. The output is simplified into two primary feedback methods: a numerical score ranging from 0 to 100, representing the progressive functional deterioration, and a visual "Traffic Light" system. This color-coded feedback, combined with haptic vibration and LED indicators, provides the user with early warnings and preventive alerts regarding their motor control status.
This "closed-loop" design ensures that the device is not just a data logger, but an active monitoring tool. By housing the power management, the processing unit, and the feedback interface within a compact wearable form factor, the bracelet becomes an autonomous unit ready for real-world clinical assessment.
Project Concept & Design Evolution
The system is conceived as a modular bracelet strategic to capturing significant data regarding arm tremors, range of motion, and movement smoothness. The initial functional logic, as defined in my very first rough sketch, centered on using the IMU to process Range of Motion, Movement Variability, and Smoothness, leading to a simple numerical score (0-100) and traffic light feedback system.
Building upon that initial logic, during Week 2, I advanced the concept by creating more detailed design representations. This iteration involved developing a specific visual form factor that transitions the theoretical device into a wearable product. These designs refine the aesthetics of the bracelet, defining the integration of the display and the overall look of the protective shell. You can explore the full computer-aided design process in the Week 2 documentation.
Simultaneously, I leveraged SolidWorks to develop a precise 3D model of the bracelet housing. This CAD iteration was crucial for defining the physical dimensions and component fit, establishing a foundation for future manufacturing. The resulting design features a robust yet streamlined casing that encapsulates the electronics and presents a clear visual interface for user feedback.
The transition from the very simple logical sketch to these detailed 3D representations highlights the early stages of product development, ensuring that the theoretical functional segments are grounded in a manufacturable and ergonomic hardware design.
Hardware Strategy & Motion Analysis
Following the electronics production path established in Week 4, the final device is powered by the Seeed Studio XIAO nRF52840 Sense. This microcontroller was selected for its integrated 6-axis IMU and its ability to handle complex data fusion. To achieve full 9-axis orientation tracking, I have integrated an external TLE493D 3D Magnetic Sensor via I2C. This combination allows for precise movement reconstruction, providing a stable reference to calculate movement quality.
Beyond motion, the bracelet incorporates a clinical dimension by using the MAX30102 Pulse Oximeter. This sensor enables the real-time acquisition of Heart Rate (BPM) and Blood Oxygenation (SpO2). To provide immediate feedback to the user, the system features an SH1106 OLED Display. This visual interface is programmed to show both the biometric data and the results of the motion analysis, creating a comprehensive health monitoring gateway on a flexible copper tape bus.
The primary metric for assessing "smoothness" is Jerk (the rate of change of acceleration). While acceleration measures speed changes, Jerk quantifies how abruptly those changes occur. In a medical context, smooth movement is characterized by low jerk values. Erratic or uncontrolled movements—often seen in motor control disorders—produce high jerk spikes. By visualizing these spikes alongside heart rate on the OLED, the device quantifies functional deterioration that might otherwise remain invisible.
Interactive Kinematics: Understanding Jerk
Use the dropdown below to simulate the difference between a healthy, smooth movement and an uncontrolled, jerky movement. Notice how sudden steps in Acceleration translate into massive spikes in the Jerk graph.
Using the 9-axis fusion (Accelerometer + Gyroscope + Magnetometer), the firmware will be able to filter out gravitational noise and focus strictly on the Dynamic Jerk produced by the user. This data will be the foundation for the 0-100 quality score and the traffic light feedback system described in the initial conceptual sketches.
Bill of Materials
Movement Quality Bracelet - Full Sensor Suite
| Component | Specification | Qty | Function |
|---|---|---|---|
| XIAO nRF52840 | Sense Version (Integrated IMU) | 01 | Controller |
| TLE493D | 3D Magnetic Sensor (I2C) | 01 | Magnetometer |
| MAX30102 | Pulse Oximeter & Heart-Rate | 01 | Biometric |
| SH1106 OLED | 1.3" Display (I2C) | 01 | Visualization |
| Vibration Motor | 3V Coreless Haptic Actuator | 01 | Feedback |
| Copper Tape | Adhesive Conductive Strip | -- | Flexible Bus |
| LiPo Battery | 3.7V 100mAh Rechargeable | 01 | Power |
| Housing | Flexible TPU / 3D Printed | 01 | Structure |