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Original Article: from Adaptivepath Blog

This entry was posted on Tuesday, August 14th, 2007 at 10:36 am by Alexa.


Challenged by an open letter that diabetes patient Amy Tenderich wrote to Steve Jobs, the American experience design consultancy Adaptive Path developed Charmr, an experience design concept to project how insulin pumps and glucose meters might work five years from now.

As reported in CNet News, Charmr is “a prototype for a sleeker, more functional blood glucose monitor and an insulin pump that users can apply directly to their bodies as an adhesive.”

“They researched extensively, interviewing diabetics and consulting with Tenderich, a valuable source of information and a link to the diabetes community.

While the Charmr vaguely resembles an iPod Nano, it has an appeal of its own. The device allows users to monitor the trends of their blood sugar levels, as well as administer insulin via a sweat-proof patch. Not to mention, the device allows for wear on the wrists, or as a keychain or necklace–all of which let the device simply appear to be another mysterious gadget, as opposed to a complex medical apparatus. Furthermore, the Charmr will triple as a USB drive that allows users to view daily trends and patterns of their condition, and other special features.”

The displays on leading insulin pumps today are the size of PDA screens and use a number of hard keys for navigation. Was it even realistic to create an adequate, easy-to-understand interface using a 2 x .75 inch touch-screen half the size of my Nokia N73’s screen?


Dan Saffer and I began the interaction design process by examining the options and screen content in existing devices. Identifying what our participants actually used, we sought out the “essence” of the insulin pump.

The “Ah-ha!” moment for me was recognizing that the interface that most type 1 diabetics today are interacting with is nothing more than a simple syringe.


All there is to this “interface” is:

  1. A way to select the amount of insulin you need (either by dialing it in or by withdrawing the appropriate amount from a vial), and
  2. A way to deliver the insulin (which provides clear feedback that it’s working: seeing the insulin disappearing into your body and the feeling of pressing the plunger makes you feel in control).

The rest of the details are dealt with in the mind.

As one of the barriers to adopting pumps today is perceived complexity, our goal became to create an interface that is no more intimidating than dialing in your insulin needs on a pen. Additionally, the device needed to provide just enough “smarts” to take away true mental burdens (like calculating your insulin dosage using your carb-insulin ratio), while keeping the user in control.

With these principles guiding us, we delved into the interaction design details: What features should the Charmr have? What feature will be used the most (dosing)? Which buttons would be soft (most of them) and which hard buttons we would need (a back button)? What is the minimum button size for a hand-held touch-screen device (many kiosks use 16mm square, whereas the iPhone uses considerably smaller, 9mm square buttons)? Which information should be shown on which screens to support particular tasks?


We also spent a bit of time discussing what kind of imagery would make the best ambient display of status (the mood ring screen). Amy Tenderich told us that one of diabetics’ greatest struggles is with guilt. They look at the numbers and feel guilty all the time. Thus, the ambient display needs to visually represent your status without assigning “moral value” to high or low blood sugar — the way a thermometer might show blue or red; neither is inherently bad.

We considered virtual pets, lava lamps, color abstracts, weather, and simply a personal/family photos theme (because it’s family or a particular goal that often motivates people), and finally concluded that the device should offer multiple themes and allow the user to choose what motivates them.


Finally, I developed a skin for the interaction design, striving to make it compelling and modern, while avoiding both “medical device blue” and the iPhone look and feel. The user could customize both the themes and the skins to their tastes, and perhaps even download more skins and themes online.


With the screen designs as well as a rudimentary industrial design concept completed, we put together an Experience Blueprint (4mb pdf), then it was time to tell the story of the product.