As part of an Interaction Design project at the Corcoran College of Art and Design, we were tasked to redesign a machine interface. I chose to tackle the grocery self-checkout. As part of my research, I interviewed users on their interactions with these machines. This user's response summed up several problems with the machine:

"I find these machines offer the promise or tease of a fast checkout, but they confuse people so they are often much slower than you hope.I wish there was an easier way to find your fruit or vegetable when you weigh it.
I always bring my bags, and agree with the feedback below that it doesn’t read that. Also, what if I am putting things directly into my bag at my shoulder, it often wants the items place in the bagging area. I don’t understand why the credit card system isn’t integrated. often it is difficult to find the credit card area. It is not easily marked. And sometimes the credit card machine asks redundant questions. Often I don’t like the voices. They are loud. I am sure that is because they don’t want you to steal, so I end up feeling not trusted. I think it should only be for express checkout. Last week I got behind an older person that had about 30 things to checkout, then she scanned coupons, then she had to bag. it took a really long time. She would have been better served with a person that works there. “

In working on the redesign, I created several paper prototypes, both low resolution and high resolution, for user testing purposes. Feedback was used to inform each iteration of the redesign. Included here is a poster showing the overall flow of the function of the machine, flowchart examples, a rendering of the new design, examples of the touchscreens, and photographs of an early paper prototype.