Stochastic Resonance Insole for Diabetic Balance Project

ISEF Category: Biomedical Engineering

Subcategory: Biomedical Devices  ·  Difficulty: Intermediate  ·  Setup: Home Setup  ·  Time: 1 to 2 Months

The Hook

Diabetic neuropathy makes the soles of the feet feel like they are wrapped in cotton. People fall more because the brain receives less information from the ground. Adding tiny random vibrations under the foot is called stochastic resonance, and studies show it can restore balance. A few coin motors and an Arduino make a research-grade prototype.

What Is It?

Stochastic resonance is a phenomenon where adding a precise amount of random noise to a weak signal makes it easier for a system to detect that signal. Sensory neurons in the foot benefit from sub-threshold vibration.

Coin motors driven by random PWM produce that vibration. Embedded in a foam insole, they deliver background noise the wearer cannot consciously feel.

A Wii Balance Board records center-of-pressure (CoP). Comparing CoP sway with and without stochastic vibration measures whether balance improves. The study runs as a within-subject crossover with healthy and family-friend recruits.

Why This Is a Good Topic

Sensory-augmentation wearables are an active rehab research area and the engineering is approachable. You will learn random-signal design, balance measurement, and within-subject experimentation.

Research Questions

• How does vibration amplitude change CoP sway area?
• What is the effect of random vs. deterministic vibration on sway?
• Does the resonance peak shift with subject age?
• To what extent does foam-insole stiffness affect outcomes?
• Which frequency band of noise gives the largest sway reduction?
• How does shoe type affect transmitted vibration?
• What is the effect of trial duration on detected improvement?

Basic Materials

• Coin vibration motors.
• Arduino or ESP32.
• LiPo battery.
• Foam insoles.
• Used Wii Balance Board.
• Informed-consent template.
• Tape and markers for foot placement.

Advanced Materials

• Force plate-grade balance system.
• Clinical mentor for diabetic-cohort recruitment.
• High-fidelity vibration actuators.
• Calibrated tactile threshold tester.

Software & Tools

• Arduino IDE: Programs the motor controller.
• Python (xwiimote): Reads the balance board.
• Python (NumPy and SciPy): Computes CoP sway metrics.
• Matplotlib: Plots effect sizes.

Experiment Steps

1. Document vibration limits and consent in writing.
2. Calibrate motor amplitude using an accelerometer.
3. Lock foot placement and stance width per subject.
4. Randomize condition order across vibration on, off, and sham.
5. Compute CoP sway metrics per trial.
6. Compare effect sizes to published stochastic-resonance results.

Common Pitfalls

• Picking subjects who can hear the motors and breaking the sham.
• Letting batteries droop between trials, changing vibration.
• Recording only one trial per condition.
• Skipping a sham control.
• Reporting only mean CoP without distribution statistics.

What Makes This Competitive

Document informed consent and a written safety review. A competitive project runs randomized condition orders, multiple trials per subject, and reports effect sizes with confidence intervals. Comparing your vibration thresholds to published stochastic-resonance studies adds rigor.

Project Variations

• Add vestibular noise via headphones to test multi-sensory resonance.
• Replace coin motors with piezo benders.
• Test the insole during stair descent.

Learn More

• PubMed: Search stochastic resonance balance insole reviews.
• NIH PubMed Central: Open-access diabetic neuropathy papers.
• Wii Balance Board open-source driver documentation.
• MIT OpenCourseWare: Course 9.07 Statistics for Brain and Cognitive Science.
• American Diabetes Association: Open educational materials.