Unifone was Tre's (Andreas Hollatz) brainchild and ended up being the project that directly led to his Master's degree/thesis. Tre built all the hardware and the software for the project. Luckily for me, David and Tre let me collaborate on the paper writing, illustrations and the stats.
The idea was cool: accessorize the sides of a mobile device with sensors to measure grip information (e.g. squeezing the sides to go to the multi-tasking menu) to assist with one-handed use. This was close to 7 years (the TEI paper cited here was from work done in 2010) before HTC introduced a mobile device with similar functionality.
Here's a short video of Unifone in action:
Excerpt from the paper published in TEI'13
We present Unifone, a prototype mobile device that explores the use of auxiliary finger input in one-handed mobile interaction. Using force-distributed pressure sensing along the side of device, we examine how squeeze-based gestures impact four common mobile interactions: scrolling, map navigating, text formatting, and application switching.
We evaluated the use of Unifone in these tasks using one-handed interactions by the non-dominant hand. Our user study shows that one-handed isometric gestures perform best when they augment rather than restrict or alter the primary pointing action of the thumb and, generally, are suitable for coarse isometric pressure input.
David Holman, Andreas Hollatz, Amartya Banerjee, and Roel Vertegaal. 2013. Unifone: designing for auxiliary finger input in one-handed mobile interactions (TEI ’13)