In STEM II, taught by Dr. Kevin Crowthers, students work in groups of four to five to design and build
an assistive technology device for a real client. My group, Team MassAssist, consists of
Mohammad Golji, Salman Azzimani (me), Abhiraam Venigalla, and Suhrit Ghosh.
DigiGuard: Modular Wearable for Adaptive Finger Tremor Stabilization
Problem Statement
Patients with neurodegenerative diseases such as ALS, Parkinson's Disease, and Multiple Sclerosis
frequently develop involuntary finger tremors. These tremors reduce grip control and make routine
daily tasks difficult, including typing, eating, buttoning a shirt, and pressing small buttons.
Existing tremor-suppression devices target the wrist or hand as a whole and rely on
neurostimulation, which does not work for ALS patients. They are also expensive, often costing
over $1,500. No affordable, finger-specific solution currently exists on the market.
Design Approach
Three designs were evaluated using a Pugh Chart weighted against 18 requirements across functional,
physical, cost, and user categories.
The device is designed to cost under $125, be worn on one or more fingers with a cuff around the
wrist and forearm, and preserve the user's ability to make voluntary hand movements.
Prototype
The final prototype consists of a 3D-printed finger enclosure, a servo motor mounted to a wrist
cuff, a spring attached from the servo to the finger mount, and a BNO085 accelerometer for
tremor detection. The Arduino monitors acceleration data and triggers the servo to wind the
spring when tremor-like oscillations are detected. Testing across 1,464 measurements over five
wound/unwound cycles showed a mean tremor reduction of 84%, with statistically significant
differences between wound and unwound states (Welch's T-test, p approximately 0). Over 66% of
volunteer participants rated the device a 7 or higher out of 10 for tremor suppression during
simulated testing.
