Project

# Title Team Members TA Documents Sponsor
68 Insole Pressure Sensing System for Running
 Aarush Sivanesan
Joseph Casino
Matthew Weng
 Xiaodong Ye design_document1.pdf
final_paper1.pdf
presentation1.pdf
proposal1.pdf
video
Members:
Joseph Casino (jcasino2)
Aarush Sivanesan (aarush2)
Matthew Weng (mw87)

# Problem
Runners often develop injuries or inefficient running form due to high impact forces, poor foot-strike mechanics (heel vs midfoot), asymmetrical loading, or inconsistent cadence. Most runners do not have an easy way to measure how their foot actually loads the ground over time, since gait labs and force-sensing soles are expensive and geared towards physical therapy, research, or professional athletics. Existing consumer wearables estimate cadence using wrist/hip motion, but do not directly measure foot-ground pressure/impact. There is a need for a low-profile, shoe-integrated system that can quantify foot impact and pressure distribution during real runs while remaining comfortable, lightweight, and accessible to everyday runners.

# Solution
We propose a thin-film pressure sensor insole system for running shoes that measures the force applied by the foot to the ground throughout each stride. A flexible sensor array embedded on top of the shoe foam (or placed under the insole) will capture pressure through the foot’s main contact points (forefoot, heel, and midfoot). A small electronics module will attach to the shoe heel or tongue and contain MCU, battery, and Bluetooth modules. The MCU will sample the pressure sensors, detect foot-strike events, and compute basic metrics such as step count, cadence, contact time, and estimated distance (using cadence/stride-length calibration and optional IMU/GPS data). Data will be streamed over Bluetooth Low Energy (BLE) to a phone for visualization, logging, and further analysis.

# Solution Components

**Subsystem 1: Thin-Film Pressure Sensor Insole Array**

This subsystem senses foot pressure at key regions of the shoe to capture impact patterns and pressure distribution during stance. The sensor insole would fit either on top or bottom of the foam insole of the shoe.

Components:
- Thin-film force sensors (multiple locations): Interlink Electronics FSR 402
- Flexible interconnect/cabling: FFC/FPC cable (0.5 mm pitch) (generic)
- Connector (board-side): Molex 503480-0490 (4-pos FFC/FPC connector) (size can be adjusted based on channel count)

**Subsystem 2: Analog Front-End + ADC Data Acquisition**

This subsystem converts each sensor data to data that can be read to the MCU. To sample all the sensors on the foot, we sample between all the sensors with a MUX. We then properly filter and amplify the data from the sensor through the op-amp. This data then gets digitized through an ADC.

Components:
- 16-bit ADC: MCP3425A0T-E/CH
- Analog multiplexer: CD74HC4067SM96
- Op-amp: TLV9062IDR

**Subsystem 3: Microcontroller + BLE Wireless Telemetry**

This subsystem houses our MCU which will control sampling,collect data, timestamp data, and transmit results via BLE.

Components:
- MCU module: ESP32-C3-WROOM-02
- Programming/debug interface: Tag-Connect TC2030-IDC

**Subsystem 4: Optional Motion Sensing (IMU)**

This extra subsystem provides accelerometer/gyro data to gather speed data, estimate and improve stride data and length, and improve cadence robustness when the pressure signals are noisy.

Components:
- 6-axis IMU: ST LSM6DSOXTR or equivalent

**Subsystem 5: Power Management + Charging**

This subsystem powers the in-shoe electronics safely and supports rechargeable operation if applicable. The design regulates battery voltage to stable rails for the MCU and sensors. We have a wide range of batteries that we would like to work with initially to weigh out the pros and cons of each.

Components:

Battery options:
- 3.7V Li-Po (300–500 mAh)
- 3V Coin Battery
- AAA Alkaline Battery
- BMS IC for Li-Po : MCP73831T-2ACI/OT
- 3.3V regulator : MCP1700T-3302E/TT

**Subsystem 6: Phone Interface / Data Visualization**

This subsystem provides the wireless interface between the device and a smartphone or website which displays metrics to the runner and logs sessions. Initial versions can use a simple BLE GATT service viewed in a standard BLE app; a custom website or phone UI can be added if time permits.

Components:
- BLE GATT profile (firmware-defined)
- Prototype viewer: nRF Connect app or alternative

# Criterion For Success

Efficiency: The system shall sample plantar pressure sensor data at a minimum rate of 100 Hz and transmit the data over Bluetooth Low Energy with no more than 5% packet loss during continuous operation.

Accuracy: The system shall detect foot-strike events and report running cadence with an accuracy of ±3 BPM compared to a stopwatch or smartwatch reference over a controlled running trial.

Continuity/Longevity: The device shall operate continuously for at least 1 hour on battery power while performing active sensing and BLE data streaming.

Four Point Probe

Simon Danthinne, Ming-Yan Hsiao, Dorian Tricaud

Four Point Probe

Featured Project

# Four Point Probe

Team Members:

Simon Danthinne(simoned2)

Ming-Yan Hsiao(myhsiao2)

Dorian Tricaud (tricaud2)

# Problem:

In the manufacturing process of semiconductor wafers, numerous pieces of test equipment are essential to verify that each manufacturing step has been correctly executed. This requirement significantly raises the cost barrier for entering semiconductor manufacturing, making it challenging for students and hobbyists to gain practical experience. To address this issue, we propose developing an all-in-one four-point probe setup. This device will enable users to measure the surface resistivity of a wafer, a critical parameter that can provide insights into various properties of the wafer, such as its doping level. By offering a more accessible and cost-effective solution, we aim to lower the entry barriers and facilitate hands-on learning and experimentation in semiconductor manufacturing.

# Solution:

Our design will use an off-the-shelf four point probe head for the precision manufacturing tolerances which will be used for contact with the wafer. This wafer contact solution will then be connected to a current source precisely controlled by an IC as well as an ADC to measure the voltage. For user interface, we will have an array of buttons for user input as well as an LCD screen to provide measurement readout and parameter setup regarding wafer information. This will allow us to make better approximations for the wafer based on size and doping type.

# Solution Components:

## Subsystem 1: Measurement system

We will utilize a four-point probe head (HPS2523) with 2mm diameter gold tips to measure the sheet resistance of the silicon wafer. A DC voltage regulator (DIO6905CSH3) will be employed to force current through the two outer tips, while a 24-bit ADC (MCP3561RT-E/ST) will measure the voltage across the two inner tips, with expected measurements in the millivolt range and current operation lasting several milliseconds. Additionally, we plan to use an AC voltage regulator (TPS79633QDCQRQ1) to transiently sweep the outer tips to measure capacitances between them, which will help determine the dopants present. To accurately measure the low voltages, we will amplify the signal using an JFET op-amp (OPA140AIDGKR) to ensure it falls within the ADC’s specifications. Using these measurements, we can apply formulas with corrections for real-world factors to calculate the sheet resistance and other parameters of the wafer.

## Subsystem 2: User Input

To enable users to interact effectively with the measurement system, we will implement an array of buttons that offer various functions such as calibration, measurement setup, and measurement polling. This interface will let users configure the measurement system to ensure that the approximations are suitable for the specific properties of the wafer. The button interface will provide users with the ability to initiate calibration routines to ensure accuracy and reliability, and set up measurements by defining parameters like type, range, and size tailored to the wafer’s characteristics. Additionally, users can poll measurements to start, stop, and monitor ongoing measurements, allowing for real-time adjustments and data collection. The interface also allows users to make approximations regarding other wafer properties so the user can quickly find out more information on their wafer. This comprehensive button interface will make the measurement system user-friendly and adaptable, ensuring precise and efficient measurements tailored to the specific needs of each wafer.

## Subsystem 3: Display

To provide output to users, we will utilize a monochrome 2.4 inch 128x64 OLED LCD display driven over SPI from the MCU. This display will not only present data clearly but also serve as an interface for users to interact with the device. The monochrome LCD will be instrumental in displaying measurement results, system status, and other relevant information in a straightforward and easy-to-read format. Additionally, it will facilitate user interaction by providing visual feedback during calibration, measurement setup, and polling processes. This ensures that users can efficiently navigate and operate the device, making the overall experience intuitive and user-friendly.

# Criterion for Success:

A precise constant current can be run through the wafer for various samples

Measurement system can identify voltage (10mV range minimum) across wafer

Measurement data and calculations can be viewed on LCD

Button inputs allow us to navigate and setup measurement parameters

Total part cost per unit must be less than cheapest readily available four point probes (≤ 650 USD)

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