A DIY programmable switch interface that allows users with limited mobility to control computers using one or two adaptive switches. Built with an Adafruit Feather ESP32-S3 Rev TFT board, it features a built-in color display, two 3.5mm switch ports, and USB keyboard emulation of the Blockly keyboard shortcut commands. The device cycles through customizable keyboard commands, making computer access possible for users who cannot operate standard keyboards.
Primary Users: Individuals with motor impairments (cerebral palsy, muscular dystrophy, spinal cord injuries) who use adaptive switches for computer access and would like to complete in block based coding.
Builders: Occupational therapists, AT professionals, special education teachers, makers, family members, and caregivers creating affordable assistive technology solutions.
Skill Level: Intermediate - requires basic soldering, CircuitPython programming, and 3D printing.
✓ Two 3.5mm jack ports for standard AT switches
✓ Built-in 240×135 color TFT display
✓ USB HID keyboard (works with all computers, no drivers needed)
✓ Fully customizable keycode list
✓ 3D printable enclosure
✓ Open-source hardware and software
- Adafruit Feather ESP32-S3 Rev TFT (~$25)
- 2× 3.5mm mono jacks (~$2)
- Wire, screws, 3D printed enclosure
- Total Cost: ~$30 (vs. $200-500 for commercial alternatives)
⚡ ELECTRICAL HAZARDS - Ensure proper insulation and connections. Test thoroughly before use.
💻 DEVICE BEHAVIOR - Sends keystrokes to whatever application has focus. Test in safe environments first.
- Consult with occupational therapists or AT specialists for assistance
- Professional assessment recommended for switch placement and configuration
- This device should complement, not replace, professional AT services
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
You are free to:
- Share — copy and redistribute the material in any medium or format
- Adapt — remix, transform, and build upon the material for any purpose, even commercially
Under the following terms:
- Attribution — You must give appropriate credit to the original creator, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
- ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same CC BY-SA 4.0 license as the original.
- No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
Attribution Format: "Adaptive Switch Interface Device" by Zero Day Camp, licensed under CC BY-SA 4.0. Available at [Blockly Accessible Interface].
When sharing modifications or derivatives:
- Maintain all safety warnings and disclaimers
- Clearly indicate what changes were made
- Share improvements back with the community
- Use the same CC BY-SA 4.0 license
This open-source approach ensures the assistive technology community can freely build, improve, and share solutions while protecting creators and maintaining safety standards.
This project is provided "as-is" without warranties of any kind. The creator is not liable for any damages, injuries, or losses from use or misuse. You assume all responsibility for safe construction, testing, and operation. Build and use at your own risk.
Build instructions and video are available here
Roadmap for this project includes:
- Creating a wireless bluetooth version
- Creating a solderless version using the micro:bit controller
Feedback? Please report any issues and bugs.