Know someone who has trouble operating a conventional computer input device, like a mouse, keyboard, joystick, or game controller? You can create your own device that is adapted to a particular person's needs and capabilities. Do they need a mouse they can click with a foot pedal or that moves by tilting, or a customized keyboard with big buttons? Could they use an adapted video game controller with a special joystick and knee-operated buttons? Could they use a "sip-n-puff" device controlled by their breath, or a no-touch gesture sensor?
Adafruit's CircuitPython lets you emulate standard keyboards and mice, or create your own custom HID devices. You can also use Arduino. Nearly all our microcontroller boards support HID. You can use USB, and on those boards that support it, BLE Bluetooth. We also have many other items in our store that can be part of an assistive technology project. Some are listed here.
For ideas and success stories of DIY assistive technology, check out atmakers.org.