Blind and visually impaired people rely on non-visual feedback when entering text. Smartphones offer the possibility of virtual keyboards which, however, offer little haptic feedback and are slower than physical keyboards.
Other keyboards, such as electronic Braille keyboards, offer more haptic feedback options, but are not suitable for mobile use because they (unlike smartphones) have to be stored on a fixed surface when operated.
Oskar is a chord keyboard (without fixed pad) for text input on smartphones. Oskar is based on commercially available components and interfaces such as Bluetooth and USB.
Oskar is four times faster than a virtual keyboard for the blind.