Donn Koh's profile

Microsoft Arc Touch Mouse
Industrial Design
Design Team:
Jonah Becker, Claude Zellweger, Scott Croyle (Owners and Principals of One & Co)
Cory Worth, Donn Koh (One & Co Design Team)
Young Kim, Monique Chatterjee, Dave Zucker (Microsoft Industrial Design & Engineering Team)

Please do not reproduce in any form or post on blogs without the expressed written consent from Donn Koh.
Contributed the Final Mechanism Concept, with One & Co & Microsoft

After the huge sucess of the first generation folding Arc Mouse (by One & Co.), Microsoft wanted to take the next leap - ‘How do we design an ergonomically generous and comfortable mouse to flatten completely for travel and storage?’
The Problem: How to Get from Flat to Volume

Microsoft came to One & Co for explorations of different ways and mechanisms to get a mouse to transform from flat to an ergonomic shape. The key challenges were firstly, for the flat state to be as thin as possible and secondly, to find a way to have the ergonomic state stay rigid and not flatten out during use.
The Ideal Solution: Go from Flexible to Rigid

The optimal, simplest user experience would be a solution that would bend and magically stay in a rigid arc shape. It should feel effortless - without any hook systems or extra steps.
Quick & Dirty Solutions Exploration with One & Co Team

As a team, we explored a variety of mechanical-principles and material properties-based solutions that could be used to tackle the flat-to-arc transition. Some ideas were demonstrated as quick mechanical models that the client Microsoft team could interact with.

* Note: The mechanical solutions shown above are not mine alone but borne out of teamwork
Sketch Exploration with One & Co Team

Some ideas were illustrated as sketches, capturing some initial aesthetic directions as well. At this point, most of the ideas either still required too many steps for the transformation, or did not provide enough rigidity in the ‘arc’ state.

* Note: The sketches shown above are not solely mine but borne out of teamwork together with Cory Worth (project lead) and Jonah Becker (owner), they are included to show the holistic thinking process behind the project.
The Inspiration: Bimetallic Strips & Differential Expansion

I remembered the phenomenon of bending bimetallic strips that was taught in middle school science classes and imagined that the same principle of differential expansion could possibly be the solution to the mechanism that would cause the mouse to go from flat state to an ‘arc’ state.

Translating the Bimetallic Principle into a Mechanical Prototype

Inspired by the possibility afforded by the example of the bimetallic strip, I tried to envision how the same principle could be used to create the flat-to-arc transformation. The illustrations below explain how the mechanical principle was conceptualized and developed.
Using the logic of the arcing of the bimetallic strip, if two layers were bonded at one end and then bent, the bottom layer would slide out, as if longer than the upper layer.

If there could be a way to secure the relative positions of these two planes when arced, it would be able to hold the arc shape rigidly.
Making use of this phenomenon, I imagined a simple locking mechanism in the form of a raised dome. When the layers have been bent so much that dome slides past the end of the upper layer, it would snap into place and lock over the rear edge of the upper layer. This would prevent the reverse sliding, and thus create the rigidly locked arc position.
To unlock the arc, the only requirement is to apply sufficient force to straighten it such that the friction at the locking edge is overcome, allowing the upper layer to ride over the dome
This simple locking solution allowed me to quickly proceed to build a mechanism model that could demonstrate the principle. In fact, based on the same principle of arcing sliding planes, any other forms of locking mechanism that are more robust for mass production would also work.
The quick-&-dirty ABS model to demonstrate the principle of the twin sliding planes in creating a lockable arcing mechanism.
Proposing the Solution

The ‘bimetallic-strip-inspired’ mechanical concept was presented to the Microsoft ID team. To ensure that the concept’s potential could be more thoroughly evaluated, quick rough sketches were used to communicate the
excitingly sleek proportions that could be afforded by this new mechanism.

The real clincher was when the client got to interact with the mechanism model made quickly from ABS sheets, it generated a lot of excitement about its possibilities. It seemed that the Microsoft team felt they had on hand the very solution to create the magical arc transformation they sought to find through One & Co.
Production Engineering Development by Microsoft

My role was completed after contributing the final mechanical concept which led to the bending and automatic locking mechanism. It provided Microsoft with the mechanism inspiration for their engineering team to resolve and develop for production.

The images above (created by Microsoft) show the eventual production version still based on the bimetallic-inspired mechanism. Microsoft’s engineering team made numerous improvements including replacing the snap-lock with a magnetic lock. Credits to them for pulling off such an amazingly complex task.

* Images and mechanics information copyright of Microsoft IncSource -
Final Product Development and Aesthetics by Microsoft

The Microsoft industrial design team, led by Young Kim and Monique Chatterjee, brought the mechanical concept through to production, and were responsible for the final product aesthetics and production resolution.
Design Team:
Jonah Becker, Claude Zellweger, Scott Croyle (Owners of One & Co)
Cory Worth, Donn Koh (One & Co Design Team)
Young Kim, Monique Chatterjee, Dave Zucker (Microsoft Industrial Design & Engineering Team)

Please do not reproduce in any form or post on blogs without the expressed written consent from Donn Koh.

Microsoft Arc Touch Mouse

Microsoft Arc Touch Mouse

Final Mechanism Concept, with One & Co 2010, 2 months Credits: Jonah Becker, Claude Zellweger, Scott Croyle, Cory Worth, One & Co Team, Microsof Read More