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Bionic Pancreas User Interface (4/4) : FAQ

July 24th, 2015 | Sara Krugman

Why black and white? We chose to use an eInk display for this first version of the BP. And yes, eInk screens are at thier best with black and white (for now, there is color but its just not as nice yet). This may come as a surprise but we chose this display technology for its technical advantages, its look and feel, and its ease of use. eInk displays are super thin and use very low power. If the battery or device dies, the screen can leave a support message with dosage suggestions and a support phone #. They are incredibly readable in the sun, and will be quietly front lit in the dark. In terms of its design character, the device is a tool. It should be reliable, trustworthy, intentional, simple to use, and light of heart. To have used an OLED screen would have demanded bells and whistles, animations, transitions, etc. OLED screens are hard to see in the light and shine disruptively in the dark. We did not want to use device power on bells and whistles. A little story about power consumption…I was at a party in college, with friends, having a blast, I needed to test my BG (before my sensor days) and the cool new meter I had (iBGstar) was turning on and giving me an animated version of their logo and then displayed “not enough power to test BG”. This was infuriating – I know the power used to do that stupid colorful animation (which already is pretty annoying to start with when all you want to do is test your BG), would have been enough to let me test.

How did you prototype the designs for an eInk screen? We used the Yota phone and built a web app that could be viewed in the eInk screen. This was much much faster than writing our own prototyping toolkit. It allowed us to test interactions, responsiveness, contrast and refresh rates. It was critical to be able to see and interact with what we were building. It was also really cool to interact with and see how it shifts expectations and experience of using a not light emitting display. It feels more sturdy, more robust, I trust it.


Why so big? The size is mainly because there are patents protecting motors and drive train. A risk not worth taking, a lawsuit from anyone about motor design and implementation would kill the project. It is also a first version and it will get smaller, but for now the main goal and focus is integration of all the aspects and commercialization. The design was driven by the size of the screen, not the other way around.

Why batteries? The choice for using AA batteries in this version was primarily to mitigate extra risk. The less pieces of the system that are dependent on an external supplier, and that aren’t off-the-shelf, the less risk. I do however feel mixed between the benefits of a rechargeable BP and a battery operated one – both have pros and cons, and batteries might be better for some people and rechargeable might be better for others. If i’m traveling, and not sure when and where my next stop will be that has an outlet, if I lose my cord, if the rechargeable battery capacity dwindles, are all reasons why I would like a battery over a rechargeable one. One of the last rounds of user research I spoke to someone who said that everything in her life was rechargeable, Dexcom, Phone, Computer etc – why should her pump be different? And I get that, for some people, recharging is easy, dependable and cheaper. This is why diversity of options in important, and I hope that when smart pumps come to the market, there are multiple options for people to choose which works better for them and their lifestyle.

Everything is in lowercase letters! Hmm? This choice was about the character of the device, and its approachability. Lower case letters are less demanding, less assuming, and less pejorative than upper case letters. Lower case speaks to the intended character of the device by being unassuming, communicative and calm.

Can I see/use anything/everything? YES! Please do! The design files are here and the prototype is here.

Who was the team? Having a team with complimentary skills is so important, and to be able to be focused and communicate well is almost more important than the skills you have. With a team of highly motivated, opinionated and smart people, the risk of bike shedding is high but the right balance of personalities can really help to avoid it. Ed Damiano and Firas El-Khatib did an amazing job of communicating the functionality and needs of the device as well as making final decisions. Ian Jorgensen worked on prototyping and understanding the technical specifications for the screens we were working with. My focus was making sure we were on track with our design process/project management as well as conducting the user research and UX. Howard Look helped to guide our process and make sure everything we were scheming about was feasible and not out of scope. Raj Setty (Ed and Fira’s assistant) made sure we had all the things we needed and is helping to get the designs implemented well. Yoann Resmond helped to get the graphics and icons perfect. And then a handle of amazing people gave us ongoing feedback that helped shape the design.