About TREWGrip
About TREWGrip
TREWGrip LLC is a spin-off of Outlier Technologies, and the result of many unsuccessful attempts to overcome the limitations of typing on mobile devices using software. Outlier's SansWrite software, which relies heavily on boilerplate text to minimize typing, improved user productivity, but was inefficient for entering non-standardized text. Despite attempts to use handwriting recognition, voice dictation, and gesture based input, users continued to utilize keyboards for text entry. In early 2010, we started exploring this mobile productivity problem from a hardware perspective, and in July 2013 TREWGrip was born...
Mark Parker introducing TREWGrip at the Cincy Typing Challenge Finals Jeff Lashley assembling a prototype unit for CES 2015 Anne Parker help participants during the Amazing Charity Race
Our Research
RearType: Text Entry Using Keys on the Back of a Device
RearType is a text input system for mobile devices such as Tablet PCs, using normal keyboard keys but on the reverse side of the device. The standard QWERTY layout is split and rotated so that hands gripping the device from either side have the usual keys under the fingers. This frees up the front of the device, maximizing the use of the display for visual output, eliminating the need for an onscreen keyboard and the resulting hand occlusion, and providing tactile and multi-finger text entry – with potential for knowledge transfer [More...]
Google Files TREWGrip-like Keyboard Patent
In yet more Google news, the Mountain View company recently filed an interesting patent application. The patent is for a new sort of keyboard to be placed on the backside of devices. According to Patent Bolt: "Last week the US Patent & Trademark Office published a patent application from Google that reveals a method of displaying a Graphic Keyboard. The twist to Google’s invention is that it relates to providing mobile devices (smartphones & tablets) with backside sensors that act as keyboard keys for input." [More...]
Apple's Virtual Keyboard Tech Could Lead to Backside Input for Tablets
A newly-published Apple patent application reveals the company is investigating a system that helps users efficiently employ the touch type method, or typing on a keyboard without looking at one's hands, by dynamically remapping a keyboard's keys. The filing also mentions that a backside sensor array can be embedded in a tablet to create a secondary input surface. [More...]
Biomechanics of Front and Back-of-Tablet Pointing with Grasping Hands
Considering the kinematic model of the hand allows for deeper understanding of target selection on the front and on the back of tablets. The authors found that the position where the thumb and fingers are naturally hovering when the device is held results in shortest target selection times. The authors broaden our understanding of that ergonomic optimum by analyzing the touch data as well as 3D data. That allows us to model the entire hand pose [More...]
Effects of a Vertical Keyboard Design on Typing Performance, User Comfort and Muscle Tension
To circumvent the awkward pronated hand position inherent to conventional horizontal keyboards, a vertical, split keyboard was designed with flexible cushions supporting the wrists, allowing relaxed hand and arm postures. During eight twice-weekly 30-min training sessions, the performance and subjective comfort of nine experienced typists were tested. Typing speed and error percentage, and surface electromyographic activity of six forearm [More...]
Analysis of Alternative Keyboards Using Learning Curves
Objective: To quantify learning percentages for alternative keyboards (chord, contoured split, Dvorak, and split fixed angle) and understand how physical, cognitive, and perceptual demand affect learning. Background: Alternative keyboards have been shown to offer ergonomic benefits over the conventional, single-plane QWERTY keyboard design, but productivity related challenges may hinder their widespread acceptance. Method: Sixteen participants repeatedly typed a standard text passage using each alternative keyboard. [More...]
Our Development
Initial Concept
The initial concept was created in April of 2010 after a SansWrite user complained about having to sit on the floor to do her work. The idea was to simply rotate the hands 90°, and place the keys on the backside so a user could hold the keyboard and type at the same time. This concept simply tested the use of visual cues and hand-eye coordination to locate backside keys.
TREWGrip - Inital Concept
Wooden Model
The wooden model was created in January of 2012 to experiment with using curves to address reach issues. When typing keys were placed on the backside of a flat surface, the third and fourth rows proved difficult to reach. Rather than rearranging the keys or reducing the spacing, the solution was to reduce the distance by curving the keys back towards the user's fingers.
TREWGrip - Wooden Model
Functional Prototype - "Frankenstein"
The first functional prototype was completed in October of 2012, and was made of parts borrowed from USB keyboards and off-the-shelf mechanical switches. The purpose of this prototype was to experiment with reaching the third and fourth rows of keys, and to explore the learning curve results cited in the Microsoft Research: RearType study.
TREWGrip - Functional Prototype
MD01 Prototype - Cincy Typing Challenge
The first Mobile Dock prototype was completed in July of 2013, just in time for the Cincy Typing Challenge (CTC). To introduce TREWGrip on the 125th Anniversary of the McGurrin vs. Traub typing competition, sixteen prototypes were hand-built in just three-months. Although good enough for the CTC, the unit’s silicone keypad design proved to be unreliable.
TREWGrip - Cincy Typing Challenge
MD02 Prototype - CES 2014
The second Mobile Dock prototype was completed in January of 2014, just in time for the Consumer Electronics Show (CES 2014). To make it in time, shells for five units were rapid prototyped with SLA 3D printing technology. Using mechanical switches, mounted on rigid circuit boards at various angles, these units were reliable but fragile, and ultimately too expensive for production.
TREWGrip - CES 2014
Are you ready to try TREWGrip?

Purchase an R&D Kit, and try TREWGrip for yourself. The R&D Kit includes an MD03 Prototype, and the accessories needed to experiment with TREWGrip using existing technology platforms.

More Info