FastShop E-Ink Card


FastShop is an electronic ink card that allows grocery shoppers to purchase goods in real-time by tapping on the RFID price tag of the item they want to purchase.

Project Roles: I designed the product interactions for FastShop and created the visual concepts such as the ideation suite and animated gifs.

Timeline: 5 days
Team: Mahvish Irfan, Daphne Liang, and Suwei Yang
Tools: Sketch, Illustrator, Photoshop, and After Effects

Design challenge

Electronic Ink (e-ink)

“How might we use e-ink to reduce wait times during checkout?”



FastShop is an e-ink card that streamlines the checkout process for grocery shoppers. FastShop removes the need for traditional grocery checkout stands like self checkout and full-serviced checkout stations. Customers would shop with their FastShop card, tap the RFID price tag of the goods they want to purchase, review their transactions, and pay for their purchases by tapping the checkout kiosk.

Shop gif
Tap gif
Review gif
Checkout gif

Literature Review

What is e-ink?

For the first day of the design sprint, we focused on secondary and primary research. Initially, our knowledge of e-ink was limited to its usage in Amazon Kindles. However, in order to understand our opportunity space better, we familiarized ourselves with e-ink’s capabilities and completed a competitive analysis to see how e-ink is being used in stores. We found that e-ink technology is already extensively used in stores - in items such as price tags, signage, and checkout dividers.

observing people's behavior at a safeway


Into the Wild

“When I shop, I just want to get in and out and buy what I need.” - P2

Our next step was to understand our intended users better and observe their shopping behaviors. We went to a nearby Safeway and conducted six semi-structured interviews with customers. We also observed the checkout area during rush hour to see how people behave. Through our interviews at Safeway, we made several key observations that informed our design process.



Shoppers with 10 items or less preferred self-checkout kiosks even though they realized that a full-service station might be quicker.


People wanted a quick and hassle-free shopping experience, so they avoid anything that could slow down their checkout experience such as coupons.  

Generating Concepts

Rapid Ideation

On the second day of the design sprint, we synthesized our finding from primary and secondary research and formulated our “how might we” statement. We then did a braiding exercise, where we completed ten rounds of rapid concept sketching. During each round, every person had five minutes to sketch an idea and explain the concept to their team members. From the 40 ideas we generated, we narrowed it down to four concepts that we explored further.

scan'd concept

Scan'd is an e-ink shopping cart or basket that tracks purchases. At the checkout kiosk the entire cart or basket is scanned.

quickx concept

QuickX is an e-ink checkout experience. At the checkout line, e-ink floor panels will direct customers to the quickest line.

fastshop concept

FastShop is the final concept we moved forward with where customers purchase goods in real-time.

goreceipt concept

GoReceipt is an e-ink receipt that is scanned when people are in queue. The receipt is then handed to the cashier to complete the purchase.

We moved forward with FastShop because it aligned with our goals in creating an e-ink product.  



To create something new with e-ink technology, rather than refining an existing idea.


To innovate based on e-ink technology rather than replacing products with e-ink.


To utilized e-ink in a way that amplifies customer autonomy during the shopping experience.

paper prototype testing

paper prototypes

What would users do?

“Oh, this is really simple! I just need to tap to buy stuff. That’s really convenient!” - P7

On the third day of the design sprint, we focused on rapid prototyping. Under our time constraint, we created paper prototypes since it gave us flexibility and allowed us to quickly create different shopping scenarios. The scenarios we focused on were 1) buying an item, 2) purchasing weighted items such as fruits, 3) returning the first item purchased, and 4) checking out at a kiosk station.

After speaking with our participants, we came up with three insights that influence the next iteration of FastShop.  



Participants felt that FastShop would reduce the wait time at checkout stations and liked seeing their shopping progress.


Everyone was concerned about dishonest shoppers and shoplifting.


Tapping aligned with the the participants’ mental model because there are many similarities with existing services that use RFID technology.

Addressing Users’ Concerns

What About Dishonest Shoppers?

The issue of dishonest shoppers was a prevalent concern for all five participants. As a result, we conducted further secondary research and found that shoplifting or incorrect purchases at self checkouts are currently a problem at supermarkets. However, grocery stores already account for this and the money they save on labor offsets their losses. The same can be applied to FastShop. The long-run benefits of streamlining a customer’s shopping experiences through FastShop without the need for extra resources outweigh the possible losses from dishonest shoppers.

Product Interactions

Fine Tuning Fastshop

For the fourth day of the design sprint, we focused on fine tuning FastShop's product interactions through a wizard of oz approach. We took pictures of each step of the interaction and made a high-fidelity FastShop card and kiosk screen that we used for the final presentation. During our presentation, we used PowerPoint to mimic the product interactions of FastShop.

Buying an item

You tap the RFID price tag of the item and the item shows up on your FastShop card for review.

Returning an item

While you are shopping, if you decide that you no longer need an item then you would return it to its shelf and tap the price tag of the product to remove the item from your FastShop card.

process of buying and returning an item

Buying in bulk

You tap the price tag of the item as many times as needed until you get to the desired quantity.

Buying weighted items

You tap the price tag of the item and go to the nearby weight station to confirm the purchase.

process of buying bulk items

Checking out

At the FastShop checkout kiosk, you tap your FastShop card on the main screen. Your purchases will appear on the screen for your review. If everything is correct then you would choose your payment method to complete the purchase.

process of checking out

next steps

Reduce the Cognitive Load

We would like to reexamine the process of removing or altering bulk items. Currently, there are too many steps in the process which can lead to cognitive overload. To address this issue, we would need to look at how self-checkouts currently process weighted goods. We could also look at innovative shopping experiences such as the Amazon Go store.


Going Broad

During the design sprint, I learned that it is important to embrace the “blue sky" ideas and to go as broad as possible before narrowing down. This allowed me to stretch my creative thinking beyond the generic ideas that initially come to mind.

It is also important to be mindful of the intended users’ mental model. FastShop received great feedback because the tapping process of the product interactions was familiar to all of our testers.