Project :: ECE 445 - Senior Design Laboratory

#	Title	Team Members	TA	Documents	Sponsor
24	StepWise: A Smart Insole System for Real-Time Gait Analysis and Muscle Rehabilitation	Kerui Xie Nuo Pang Xiaorui Zhang Zhichao Chen		proposal1.pdf
	# Problem Despite walking being the most fundamental human movement, the majority of the population suffers from undiagnosed gait abnormalities such as Pes Planus (Flat Feet), over-pronation, and irregular strike patterns, which lead to a "kinetic chain" of health failures. When a person suffers from improper heel-to-toe transition, the misalignment doesn't stay in the foot. It forces the ankles to roll inward or outward, the knees to rotate unnaturally, and the pelvis to tilt. This creates a "Kinetic Chain" reaction that is a primary driver for chronic lower back pain, hip bursitis, and premature osteoarthritis in the knees. Because these issues develop slowly over years, most individuals do not realize their walking posture is the root cause until permanent joint damage has occurred. Currently, high-fidelity gait analysis is confined to specialized medical facilities. Systems like optical motion capture (Vicon) or pressure-sensitive walkways (GAITRite) cost tens of thousands of dollars and require trained clinicians to operate. Existing solutions are mostly passive. Traditional orthotic inserts act as a "crutch" for the foot, supporting the arch without actually strengthening the muscles responsible for maintaining that arch. # Solution Overview StepWise is a 3D-printed smart insole that replaces expensive clinical gait labs with a wearable diagnostic ecosystem. It features a 5-vital-point pressure sensor array to capture real-time foot mechanics and orientation during daily activities. Data is transmitted via Bluetooth to a mobile app, where algorithms identify pathologies like Flat Feet (Pes Planus) and muscle fatigue. To close the loop, the system provides haptic alerts for posture correction and recommends personalized exercises to actively strengthen the user's foot muscles and prevent chronic joint pain. # Solution Components ## Data Collection System - Pressure sensor array for capturing high-resolution pressure data at five anatomical foot points - Sensors for tracking foot orientation, swing velocity, and strike angles - Circuits to convert resistance change to voltage values ## Transmission System - Low-power data processing and wireless Bluetooth transmission - LiPo power management unit and protection circuit ## Diagnostic and Feedback System - Mobile Application for real-time visualization of foot pressure heat maps - Analysis Algorithm to identify pathologies - Provide physical alerts to correct poor walking posture # Criterion for Success - Successful capture of distinct pressure signatures from all five sensor points with high resolution - The 3D-printed insole must withstand 500 compression cycles - Collection system lasts for 1 hour - The algorithm accurately distinguishes between "Heel Strike," "Mid-Stance," and "Toe-Off" - Successful detection of pathologies - Generate personalized exercise routine based on the user's specific muscle fatigue data

Featured Project

# Wireless Charging Table Supporting Multiple Devices with Arbitrary Placement

# Problem

While more and more device manufacturers adopt wireless charging into their smartphones and headphones, most currently available wireless charging pads only support a single device and require strict alignment between the device and the coil. Misalignment can negatively influence both user experience and charging efficiency. In certain scenarios such as cafeterias, a table that can simultaneously charge multiple devices with arbitrary placement can be useful and COOL, allowing the users to sit wherever they like and to arbitrarily place their devices.

# Solution Overview

We intend to design and manufacture a table with multiple mobile coils placed in an intermediate layer below. Driven by step motors, a tool grabber attaches the coils using electromagnets and drop them in the right place. Computer vision will be used to recognize devices (phones, AirPods, etc.) and guide the chargers to corresponding locations. Once the coil is in place, it will first communicate with the device (Qi protocol) to verify whether the device can be charged wirelessly. If yes, the charging process will start. Otherwise, the coil will be moved back to its original location. The scheduling algorithm ensures the wires get separated and neat.

# Solution Components

* Mechanical subsystem. The main moving component of the system is a large-scale X-Y moving mechanism under the table. The coils will be placed between two panels above the moving mechanism and will be caught and dropped to the right place by the moving tool head. The tool head will be developed with electromagnets or magnets with Z-axis moving capability.

![sketch](https://courses.grainger.illinois.edu/ece445zjui/pace/getfile/18618)

* Vision detection subsystem. This includes a camera and a processing unit. It detects the locations of phones and other chargeable devices and send their positions to the control unit. In real-world settings, pre-installed surveillance cameras may be used as the video source so that no additional camera is required. Embedded GPU (NVIDIA Jetson Nano as a candidate) or cloud service can be used for image processing.

* Power supply control. It is used to control wireless chargers and supply power to devices if and only if the handshake between charger and device is successful. Status will be reported to the central control unit.

* Central control unit and embedded software. According to the output given by the vision detection system or the feedback from the power supply system, the central control unit should move the chargers with proper scheduling algorithm to pair chargers with devices and keep wires of coil separated and neat.

# Criterion for Success

* The vision detection system can localize chargeable device at an accuracy of over 80% and response within 2s.

* The power system can supply powers when a chargeable device is present, and not supply power when the misdetection happens. Correct feedback can be sent to the central control system.

* The mechanical system moves correctly according to the commands given by the central control system.

* The central control system can send correct commands to the mechanical system given the position information from the vision system and the feedback from the power supply system. It should be able to keep wires of charging coil separated.

# Evaluations on Alternative Solutions

The technology of wireless charging emerged some time ago, but its inclusion in commercial devices doesn’t take off until recent years. Intuitively, wireless charging doesn’t bring much additional convenience compared to the wired charging, but its adoption by major manufacturers has proven its value. Similarly, in certain settings such as the cafeteria, charging without alignment may significantly increase user experience, comparing to having only a few fixed charging locations.

An alternative solution to enable table-scale wireless charging is to deploy multiple coils covering the whole table. But it doesn’t solve the alignment problem unless the coils are heavily overlapped, which has been proven to be difficult by already canceled Apple AirPower.