Upright Assist is a Raspberry Pi - based assistive control system designed to improve seated stability for wheelchair users with limited trunk control. It actuates a motorized strap mechanism to provide temporary upright postural support and can be triggered either by a physical 3-position switch (center-off, two directions) or by a voice hotword.
Always encase the electronics and the spool/mechanism to protect both the device and the user. Temporarily took off for debugging in video.
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The Raspberry Pi listens for a voice hotword and reads the state of a physical 3-position switch. Based on these inputs, it commands a DC motor through a motor controller HAT to wind or unwind a strap on a spool.
A pull-type solenoid acts as a simple locking/braking mechanism against the spool: when engaged, it helps keep the spool from turning to hold strap position; when activated, it pulls back to allow the strap/spool to extend outward.
For voice activation, the software typically runs the motor for a fixed duration in a configured direction and then stops automatically.
- Dual input control (3-position switch + voice)
- Timed motor actuation for consistent support
- Cooldown protection to prevent repeated triggers
- Safe shutdown handling
- Minimal runtime dependencies
- Designed for reliability and simplicity
- Raspberry Pi (tested on Pi 5)
- Adafruit DC Motor HAT (PCA9685-based)
- DC motor with appropriate torque for the spool/strap mechanism
- 3-position switch (center-off) for manual extend/retract control
- USB microphone (for hotword detection)
- Pull-type solenoid (to lock/release the spool)
- 3D-printed spool (for winding/unwinding the strap)
- Strap material
- Wires/connectors as needed for GPIO, power, and motor connections
- Fasteners and mounting hardware (e.g., screws/clamps/brackets)
- Power bank for the Raspberry Pi and motor system (≥5V @ 3A Pi rail, ≥5A motor peak)
- Python 3
- Raspberry Pi OS
- Enabled I2C interface
pip install -r requirements.txtAll runtime configuration is defined at the top of the script:
- GPIO pin(s) for switch input
- Motor selection (motor1--motor4)
- Motor throttle and direction
- Actuation duration
- Voice hotword
- Cooldown interval
No code changes are required elsewhere.
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Power on the Raspberry Pi and motor supply
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Run the control script:
python main.py
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Activate the system by:
- Moving the 3-position switch to drive the motor in either direction (center position is off), or
- Saying the configured hotword for hands-free activation
For voice activation, the motor engages for a short, predefined interval and then stops automatically.
- Always test motor direction and duration without a user present
- Use a current-limited motor supply
- Ensure the strap mechanism cannot overtighten
- The system is intended as an assistive aid, not a medical restraint
- Supervision is required during use
- When using a single battery pack, ensure adequate current headroom and separate regulation for logic and motor loads to avoid brownouts.
- This project is not a certified medical device and is provided for experimental and assistive use only.
This project is licensed under the MIT License. See LICENSE.md for details.
Developed as an assistive solution to improve seated stability and autonomy for individuals with neuromuscular conditions. I’d like to thank Alejandro Gallo, Jesse Spencer, and Nils Hakansson for their work and help throughout this project.