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Wearable Haptic Feedback System

I am conducting research under Professor Doug Weber on developing a wearable haptic feedback system for motor learning and rehabilitation. The project centers on an ergonomic, 3D-CAD-designed wrist device with Linear Resonant Actuators (LRAs) to deliver precise vibro-tactile cues.

 

I led fabrication of the custom haptic module and am now implementing a Bluetooth-enabled PCB controller for real-time feedback. Working with a cross-functional team, we are integrating the device with a Unity-based iPad app that guides users through drawing and tracing tasks. The synchronized haptic cues and motion tracking support data-driven analysis of motor performance, with broad applications in assistive technology and human-computer interaction.

 

I am also co-authoring a research paper detailing the system architecture and initial results.

Aim: To investigate how spatially encoded haptic feedback delivered through a wearable system influences task performance and motion guidance during a drawing-based experiment.

System Architecture Design: Hardware

  • A wearable band with 4 Linear Resonant Actuators (LRA) to deliver vibrotactile cues around the forearm​

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  • Each LRA is controlled by an Adafruit DRV2605L haptic driver, routed through an I²C multiplexer (TCA9548A)​

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  • The system is powered by a Seeed Studio XIAO nRF52840 Sense microcontroller

Custom PCB & Embedded Control

Linear Resonant Actuator - Selection & Analysis

  • Critical Component Selection – The most critical part is selecting the right LRA for vibrotactile feedback, since performance relies on its resonant frequency

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  • Frequency Matching – Ensuring all LRAs share the same resonant frequency is essential for consistent and reliable haptic intensity.

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  • Validation – Power Spectral Density (PSD) analysis confirmed the resonance peak across multiple trials and signal types.

System Architecture Design: Software

Unity IPad App - Drawing Task 

Python Control Software: Multi-Mode GUI

Operational Modes:

 

  • Normal Mode – Manually adjust LRA vibration frequency and intensity

  • KeyStroke Mode – Map keyboard keys (0–9) to vibration levels for rapid testing

  • Pattern Mode – Create and replay complex vibration sequences with customizable intensity, timing, and distribution

  • Trigger Mode – Deliver haptic feedback in response to external triggers (e.g., sensors or scripts)

IMU Data

  • Real-time visualization of 6-axis IMU data on the GUI, displaying accelerometer and gyroscope outputs from the microcontroller

  • Allows the haptic band to react to motion or work with other movement-based systems

Ergonomic Iteration & Prototyping

Experimental Design

  • Users trace shapes on an iPad

  • 4 LRAs give directional feedback

  • Vibrations alert the user when they move off the guide line in any direction - up, down, left, or right

  • Diagonal drift triggers two LRAs at once

4 Test Condition:​

  • No Feedback – No cues

  • Haptic Only – Vibrates on deviation

  • Visual Only – Shows drawn line

  • Haptic + Visual – Shows line + vibrates on deviation

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