Project

# Title Team Members TA Documents Sponsor
65 Active Postural Correction Vest
Aparna Srinivasan
Jordyn Andrews
Sophia Sulkar
Frey Zhao design_document1.pdf
final_paper1.pdf
proposal1.pdf
video
# Active Postural Correction Vest


**Team Members:**
- Aparna Srinivasan (aparnas3)
- Jordyn Andrews (jandr25)
- Sophia Sulkar (ssulkar2)


# Problem


Poor posture is an extremely common issue in modern society, especially in the workplace, where employees sit and slouch for hours on end. Long-term slouching can lead to musculoskeletal imbalances, chronic back pain, and reduced respiratory efficiency. Existing solutions are either braces (which do not require any muscular effort from the person) or simple notification (devices that buzz but do not actually enforce correction). There is a lack of active solutions that physically assist the user in regaining proper posture without requiring constant conscious effort, or just doing all the work for them with no effort at all.


# Solution


We propose an Active Postural Correction Vest. Unlike passive braces, this system uses an active electromechanical feedback loop to physically retrain the user’s posture, while also letting go so that good posture is maintained by the user, not just the device itself.


The device consists of a wearable vest equipped with stretch sensors which attach to elastics. These sensors continuously monitor how much the elastics are extended. When the system detects a "slouch" state (shown by the stretch sensor reading shifting away from the calibrated threshold), the central PCB triggers a high-torque servo motor mounted on the back plate. The servo reels in a cabling system made of elastic connected to the shoulder straps, physically pulling the user's shoulders back into a proper position. Once the sensors detect that the user has returned to the correct posture, the servo releases tension, allowing for natural movement and self-maintained posture until the next slouch event.


In terms of safety precautions, we plan to create an assistive device that does not use a lot of force, so it cannot cause any damage. We also are going to have an emergency stop button as well as an auto shut-off when the resistance level reaches a level that is too high. We also will filter out noise by adding a timer that only activates the motors if the person is sitting in a slouched position for a prolonged time.




# Solution Components


## Subsystem 1


**Sensing and Input**
This subsystem is responsible for detecting the user's postural state by measuring the tension and force exerted by the brace straps against the body.
- Primary Sensors (Stretch Subsystem): We will use stretch sensors placed between the shoulder strap and the user's clavicle. When the user is well-postured, the straps are taut (indicated by high Resistance/Voltage). When slouching, the straps loosen or shift (indicated by low Resistance/Voltage).
- Secondary Sensor (Pressure Subsystem): We will also use pressure sensors on the front of the vest to provide a safety check to make sure that the strap tension stays within a comfortable limit


## Subsystem 2
**Mechanical Correction**
This subsystem provides the physical force required to retract the shoulders.
- Actuator: We will use a Servo motor, which will be able to reel in the elastic band without being too powerful or dangerous.
- Mechanism: The servo will be mounted on a central back plate, which could be 3D printed, using a spool-and-cable mechanism to shorten the effective length of the shoulder straps.
## Subsystem 3
**Control & Power**
This subsystem processes sensor data and drives the motor.
- Microcontroller: possibly an ESP32 for wireless support
- Power Regulation: batteries, etc.
- Failsafe: Kill switch/button


## Subsystem 4
**Bluetooth App**
A Bluetooth-connected app will display posture behavior over time (how often and how long the user slouches). The app would also allow adjustment of sensitivity and comfort limits, and let the user switch between training and brace modes.

# Criterion For Success

- The system shall detect a slouched posture when the stretch sensor output drops below a calibrated upright threshold for >= 30 seconds.

- Normal movements such as walking, reaching, or twisting shall not trigger motor actuation during a 10-minute movement test.

- When a slouch is detected, the servo shall retract the shoulder straps by a fixed amount of mm within 10 -15 seconds, resulting in visible shoulder retraction.

- The servo shall fully release strap tension within 5 seconds after the stretch sensor returns above the upright threshold.

- Strap pressure shall remain below a predefined safe limit, and the system shall disable the motor immediately when the emergency stop button is pressed.

- The vest shall operate continuously for at least 4 hours on battery power while maintaining full sensing and actuation functionality.

Electronic Automatic Transmission for Bicycle

Tianqi Liu, Ruijie Qi, Xingkai Zhou

Featured Project

Tianqi Liu(tliu51)

Ruijie Qi(rqi2)

Xingkai Zhou(xzhou40)

Sometimes bikers might not which gear is the optimal one to select. Bicycle changes gears by pulling or releasing a steel cable mechanically. We could potentially automate gear changing by hooking up a servo motor to the gear cable. We could calculate the optimal gear under current condition by using several sensors: two hall effect sensors, one sensing cadence from the paddle and the other one sensing the overall speed from the wheel, we could also use pressure sensors on the paddle to determine how hard the biker is paddling. With these sensors, it would be sufficient enough for use detect different terrains since the biker tend to go slower and pedal slower for uphill or go faster and pedal faster for downhill. With all these information from the sensors, we could definitely find out the optimal gear electronically. We plan to take care of the shifting of rear derailleur, if we have more time we may consider modifying the front as well.

Besides shifting automatically, we plan to add a manual mode to our project as well. With manual mode activated, the rider could override the automatic system and select the gear on its own.

We found out another group did electronic bicycle shifting in Spring 2016, but they didn't have a automatic function and didn't have the sensor set-up like ours. Commercially, both SRAM and SHIMANO have electronic shifting products, but these products integrate the servo motor inside the derailleurs, and they have a price tag over $1000. Only professionals or rich enthusiasts can have a hand on them. As our system could potentially serve as an add-on device to all bicycles with gears, it would be much cheaper.

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