What to Do about Handwashing?


What to Do about Handwashing?

Prototyping the Germs Away

April 20, 2020
by David Rose
Sudsing with the cat hero

Marketers try to sway our purchase decisions with emotional appeals like colorful packaging, manufactured authenticity, value pricing (“Now, with 50% more!”), and scientific authority (“Nine out of ten doctors recommend…”). How might we nudge the pro-social behavior of better handwashing with design—and a little Hollywood- or Japanese-inspired enchantment?

Since the TEDMED conference was recently in town, right near our Boston studio, we decided to make a couple of prototypes and test them. A conference center is the kind of place where handwashing is critical. Thousands of people have flown in from around the world, and all interactions start—well, they used to start—with a warm transmissive handshake. We installed our prototypes in a bathroom that all of the attendees used, including the Surgeon General, who was one of the speakers, and got feedback from infectious disease researchers and doctors.

Precedents for Ambient Devices

Behavioral change with glanceable displays is a longtime passion of mine. I created an internet-connected, color-shifting orb that made people surprisingly obsessed about the stock market, weather, traffic congestion, blood sugar levels, and steps they walked (which I presented at a previous TEDMED). Based on the insight that persistent information is persuasive, I started a behavioral health company that designed smart pill bottles that used light and sound, social sharing, and financial incentives to encourage medication adherence. A simple version of this is the wear strips for toothbrushes and razors that nudge consumption. Consider Pfizer’s Cool Blue, project, which used color to highlight plaque on your six-year-old’s teeth. As Britain’s The Sun put it: “Chewy tablets reveal just how rubbish your kid’s toothbrushing really is—and mums are raving about them.”

But why aren’t people washing their hands enough in the first place? What’s the motivation for handwashing? Is it selfless or selfish? If we could get people to wash their hands more, what other pro-social practices could we encourage them to do?


1. Paws to Wash

The inspiration for the first prototype comes from the observation that we exhibit our best behavior when we’re observed. But no one wants a Big Brother camera observing them, especially in a bathroom. Being observed by a cat, however, is tolerable. Who is a kitty going to tell? The ubiquitous waving Japanese cats provided inspiration, even more so when we discovered that they’re not actually waving—they’re washing. The cat sits on a platform that contains a proximity sensor, LED ring, and speaker. As the cat meows the Jeopardy tune over 20 seconds, the ring of light fills.

paws to wash

2. Projected Germs

When do you wash your hands the longest? When you can see how grimy they are. I experienced this when I worked in a bike shop in high school: I would scrub my hands for five minutes to get the grease off. By making the invisible germs visible and repulsive, people will see the need to keep washing. A pico projector hidden above the sink displays cartoonish germs on your hands that transition to sparkles over 20 seconds. An extra advantage of this design is that it keeps your attention focused on your hands versus humming along with a cat.

projected germs

3. Petri Dish Countdown

Iron Man has a glowing chest ring, the palladium source of his power. What if you could feel empowered in the same way? A glowing countdown is projected in reverse on your chest so that it appears the right way around in the mirror. By using your body as a canvas for information, this design feels both personal and incriminating. Marnie Chang, an illustrator on our team, designed germy numbers that appear in a petri dish to count down the germs you are washing away. We tried to name and illustrate which germs (e. coli, staphylococcus, shigella, COVID-19) are washed away in which order but couldn’t get scientists to agree on this sequence.

petri dish

Making It Real

As designers, we know the only way to make great products is through experimentation with real people in real-time. To prototype Projected Germs and Petri Dish Countdown, we used pico projectors to display information on the user’s body. For Paws Before Washing, we modeled a little stand and a circular fill-bar of individually addressable LEDs. We “recognized” people as they stepped up to the sink by using a soap proximity sensor, then used an Arduino microcontroller with a wave sound shield to play audio.

MadeReal lab making

Testing the proximity sensor inside the acrylic base. The top was laser cut and the light holder was CNC’d in-house at the Made Real Lab at EPAM Continuum.

Sparkles on hands

Ironwoman petri dish countdown


I love the moment where we take “hardware sketches” (barely working, low-fidelity prototypes) and place them in the context of use. There is so much to learn in those first hours of interviews with a prototype. This was my first time conducting this research in a bathroom setting, surrounded by a group of guys (all with very clean hands).

After installing a prototype in the bathroom at TEDMED, we received some useful feedback from two infectious disease researchers, and a physician.

Embedded content: https://www.youtube.com/watch?v=ClD5fManOd0

Applications to Other Domains

These insights about sentinel effects (softened by cuteness), ambient visual feedback, auditory cues, and projecting information on the body could apply to other daily habits and rituals.

To stress-test this idea, I spoke with a senior executive at Procter & Gamble’s innovation lab, who responded: “The notion of making the invisible visible could enable cleaning compliance across many of our brands to promote more hygienic habits. It not only works for handwashing, but also laundry, kitchen, and household surfaces.”

Launching a DYI Open Source Project

Now we have some confidence that ambient cues and feedback are a promising way to motivate people to wash their hands longer. But how do we scale this effort? Even with a polished product design and the evidence that it changes behavior, how do we quickly manufacture and distribute them to hotel and conference venues, restaurants, travel hubs, and schools? Let’s see, where is the best place to quickly produce high-volume, affordable electronics production… oh yeah.

Since we’re all distancing at home, this is a great DIY project to do while your sourdough rises. It checks multiple goodness boxes:

  1. It draws attention to the importance of handwashing.
  2. It gives you a fun activity to do together with your kids.
  3. It teaches electronics and creative prototyping skills. 

My 11-year-old and I just assembled and installed one this week!

Embedded content: https://www.youtube.com/watch?v=ffyMcaMRMOk

how to hack

So it’s up to you to rope in your kids and make your own version, either with a pico projector or an Arduino UNO as we did, or a simpler invention kit like Makey Makey. We posted step by step instructions, links to components, wiring diagrams, and source code and a milk-carton enclosure idea on Instructables.com Have fun, be safe, and stay clean!

Read more about the Paws to Wash project on EPAM's SolutionsHub.

filed in: prototyping, healthcare

About the Author

  • RoseDavid Headshot
    David Rose

    David is a five-time entrepreneur, MIT lecturer, author, and expert on digital product innovation, computer vision, spatial computing, and the internet of things. He is a futurist at EPAM Continuum prototyping new product and service concepts that leverage emerging platforms like AI, AR/VR, wearables, embodied interaction, and affective computing.

    He is the author of Enchanted Objects: Design, Human Desire, and the Internet of Things, and holds patents for photo sharing, interactive TV, ambient information displays, medical devices, and machine learning algorithms. His work has been featured at the MoMA; covered in The New York Times, WIRED, and The Economist. He has been a guest on The Daily Show and parodied on The Colbert Report.