Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 43 | Secure Stride Walker Assistant |
Harrison Wong Janine Zhu Nick Schroeder |
Aniket Chatterjee | design_document1.pdf proposal1.pdf |
|
| # Secure Stride Walker Assistant Team Members: - Nick Schroeder (ns58) - Harrison Wong (hjwong3) - Janine Zhu (janinez2) # Problem Older adults discharged after lower-extremity surgery or hip fracture frequently transition from supervised rehabilitation to independent home recovery with limited reinforcement of safe walker use. Customer discovery interviews with physical and occupational therapists identified multiple contributors to falls during this period, including poor walker positioning, walker abandonment, unsafe turning, excessive gait speed, low-light ambulation, and unsafe sit-to-stand transfers. # Solution Stride Secure is a lightweight, reusable clip-on device that transforms a standard walker into an intelligent rehabilitation support system. Using motion sensing and proximity sensing, the device provides configurable visual and auditory cues to encourage proper walker positioning, remind patients to use their walker, promote safer walking speed, improve nighttime visibility, and reinforce safe mobility behaviors during the first 2–6 weeks following discharge. This device consists of 6 subsystems. The first subsystem is the sensing subsystem that is designed to monitor the motions of the user and the surrounding environment. The second subsystem is a feedback subsystem that alerts the user to walk at a slower pace, to use their walker, etc. The third subsystem is the mechanical mounting mechanism that mounts to a variety of walkers, but also serves as the housing for the sensors, feedback devices, and microcontroller. The fourth subsystem is the processing/control subsystem that intakes sensor data and processes it to send instructions to the feedback subsystem. The fifth subsystem is the power subsystem that powers all the electronics and maximizes battery life for a full day of operation. The sixth subsystem is the interface for users to input volume and brightness settings as well as initialize/define basic mobility states for safe and unsafe use patterns. # Solution Components ## Subsystem 1: Sensing Subsystem This system must be able to detect the walker’s motion and orientation and the user’s proximity to the walker. An IMU (MPU6050) would be used to detect falls or excessive leaning of the walker. Integrating the collected acceleration data from the IMU can be used to determine walker speed. This system will have an ultrasonic sensor (HC-SR04) to determine the user’s location relative to the walker, allowing it to detect if the user drifts too far in or out of the walker. We’re also considering a lidar camera either to replace the sensor or in tandem with it to provide a broader set of data. The determination of whether to or not to use lidar is in consideration pending further analysis by the team. ## Subsystem 2: Feedback Subsystem This subsystem provides the user with reminders based on information and data processed from the sensor subsystem and instructions determined by the processing/control subsystem. The instructions and cues are sent audio cues through a microphone. Visual cues, such as reminders to use the walker at night, would be small flashing LEDs for users who are hard of hearing or Deaf. The LEDs would also be different colors for different warnings, which colors such as Red, Yellow, and Blue for users who may be red-green colorblind. Brighter LEDs will be used to improve nighttime visibility. ## Subsystem 3: Mounting Mechanism This subsystem is the mounting mechanism for the device as well as the housing for all electronics parts such as sensors, microphones, and the microcontroller. The mounting mechanism should be adjustable for a variety of walker models. The housing can be made out of wood or 3d printed for this project and will need to account for sensor placement and feedback system optimization. ## Subsystem 4: Processing/Control Subsystem This subsystem processes sensor data to make real-time cues for the user. The subsystem will have a microcontroller (STM32U0) to intake data collected by the sensors and provide real-time instructions to the feedback system. It can use its flash memory to store data as needed, and as the most power efficient current model in STM’s lineup, it will support the need for efficient power consumption. The cues and instructions will be issued depending on predetermined/inputted mobility states to delineate what are safe and unsafe use patterns. The inputs from the interface subsystems, such as volume and brightness controls, will be processed to be reflected in the feedback subsystem as well. ## Subsystem 5: Power Subsystem This subsystem powers the device and all the electronic components. This subsystem will consist of a rechargeable battery and battery status display at its core. We will design it to be charged by USB, thus allowing us to use standard AC-DC wall power blocks and avoiding the need for an onboard rectifier. The system as whole will be designed to minimize power consumption in order to prolong battery life throughout the day. This will be achieved by selecting components specifically for power efficiency, regulating voltage to convert to the most efficient operating voltage of those devices, and allowing the system to entirely cut off conduction to elements which aren’t in use. The cutoffs will be determined by software and achieved by switching power MOSFETs (IRFI1310N) on or off. The voltage regulation can be achieved using either a switching regulator (TPS62A01DRLR) or an LDO (MIC5156YM) depending on how noise sensitive the device being powered is. ## Subsystem 6: Interface Subsystem This subsystem is for users to input volume and brightness settings as well as initialize/define basic mobility states for safe and unsafe use patterns. User inputs can be displayed on a LCD screen with a large font for users who are near sighted. Any user inputs for instruction volume or alert intensity can be adjusted with larger buttons for mobility accessibility. # Criterion For Success The device is successful if it can detect misuse of walkers by a user and provide instructions to prevent falls. The device also needs to be adaptable for a variety of walker models and configurable for different user needs. The one caveat we’re putting on it is that, with the nature of the project, we’re planning to produce a comparatively basic proof of concept prototype with functional sensing, power, and processing systems. The rest will either be an extension in the event of progress moving more quickly or considered for updates after we finish ECE 445. |
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