Vaguely reminds me of Dave Mackay's (sadly now neglected) Dasher research project[1], in that both can be used to enter text with input devices that only have a single axis.
Dasher's seems like it fits better with continuous/'analogue' input methods, though (it uses inherently continuous input, Minuum's just using the analogue entry systems to simulate a single-row keyboard).
I love dasher. It was very helpful for me in writing emails when I was unable to use one hand. One handed keyboards were actually slower once I got used to both of them. It just doesn't work well for coding, but it's great for other English.
Dasher is really cool - it's easily the most radical take on keyboards I've seen.
Sometimes I just turn it on full speed and swipe at a random angle to the right and let it fly through the infinite dictionary, watching a deterministic gibberish story unfold.
Dasher's seems like it fits better with continuous/'analogue' input methods, though (it uses inherently continuous input, Minuum's just using the analogue entry systems to simulate a single-row keyboard).
[1] home: http://www.inference.phy.cam.ac.uk/dasher/
gif showing the concept: http://www.inference.phy.cam.ac.uk/dasher/images/largedasher...
play store: https://play.google.com/store/apps/details?id=dasher.android