Making Self-Checkout Mobile

Prototyping, Service Design, UX

About | The Mobile Self-Checkout system affords grocery store shoppers the ability to select, scan and pack their items as they roam, reducing time in queues, and empowering shoppers to track their accumulative total. This project was part of an interaction design course where I was asked to ‘redesign a control’ as part of the grocery check-out experience using design principles and an interaction inventory as guides.

Contribution | Solo project

Time Frame | 3 weeks


The System

The system includes a light-weight mobile app for scanning items at the point of selection, and a saddle-shaped collapsible cart that shoppers pre-load with (reusable) shopping bags so they can pack items on the go. Pay-by-weight items are placed in the upper level for weighing at checkout, before being added to the top of grocery bags. The shopper then proceeds to their car to unload. This system is designed for environmentally-conscious couples or small families who cook regularly, shop weekly, are budget-savvy, and time-pressured.


Design Features

The Mobile Self-Checkout system affords efficiency and autonomy to shoppers. The system bundles multiple tasks into one moment so that each item only needs to be handled once. Individual items are selected, scanned, and bagged all together, rather than having to be unloaded, scanned, and bagged again at checkout. The scanning app also comes with the convenience of checking prices and tracking the cumulative total – giving shoppers autonomy over their choices, and avoiding the shock of an unexpected spend.


Interaction Inventory

Below is an inventory of the sequence of micro-interactions that occur during the grocery store checkout experience. These were unpacked using Don Norman’s design principles in an attempt to explore possible pain points or sites of intervention.


Exploratory Ideation

Using the inventory as a reference, I sketched early concept ideas for interventions that might address or improve some of the key micro-interactions or pain points that show up in the grocery checkout experience. As ideas evolved, I began to focus in on what possibilities might lie outside of the two traditional check out models – the attendant checkout and the self-checkout. The later sketches in this section are an attempt to hybridize or augment the flow of the checkout experience in order to emphasize the strengths of each. The shopping cart-mounted device received the most positive feedback during critique, seeding the next phase of ideation.


Focused Ideation

When shopping at grocery stores currently, each item is individually handled twice – once by the shopper as they select it from the shelf, and again when it is scanned at checkout. In the case of an attendant checkout, each item is individually handled a third time when loaded on to the conveyor belt. The concepts below are an attempt to simplify this using a device that bundles tasks. While these concept sketches might appear promising, on their own, none of them are able to execute all three of the tasks that checkouts perform: (1) scanning, (2) weighing and (3) bagging.


Concept Development

Instead of focusing on bundling scanning and weighing at the point of item selection, I pivoted my approach to tackle the bundling of scanning and bagging instead. This is because (a) most items don’t need to be weighed, and (b) all items needed to bagged. At the same time, previous real-life attempts at making mobile scanning devices in the early 2000’s have been eclipsed by the static self-checkouts we all know well, in part because items still require individual handling during the bagging process, making redundant any efficiency gained from scanning at the point of selecting the item off the shelf. In which case, in order to be viable, mobile checkout systems need to solve for the problem of bagging at the point of item selection, and the cart concepts below are an attempt to confront this challenge.

concept development.png

Iterating Prototype

Feedback from the first soft-pocket prototype led to a subsequent design that employed the baby-seat mechanism in traditional carts to make the V-frame collapsible. This design affords a large sturdy capacity while in use, and compact stackibility when stored. The easy-access side slots for shopping bags were inspired by pick-and-pack carts from commercial shipment centres that are pre-loaded with boxes for fast retrieval and one-step packaging of orders. The baby-seat folding mechanism provides a flat bottom for bags to rest on, avoiding the limitations of the soft-pocket prototype.

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Future Considerations

This project was intentionally scoped to rely on an interaction inventory and design principles to guide it’s form and function. With more time, I would conduct exploratory and evaluative user research to better understand how shoppers relate to their own grocery store experiences, and how a new mobile system might be integrated into their own mental models and habits. This would not only feed into form and function, but would also give insights into what the “long loop” of the experience might look like – how to support and orient first time users to adopt the new system with ease, while giving familiar users more space to move at their own pace.