This is the machine which sell and recharge laundry card in my living building.
Your assumptions as to how it’s used
If I never saw the machine, considered its function, I would assume:
1) There were 2 buttons - "new card" and "recharge".
2) Asked me insert old laundry card if I choose recharge.
3) Let me input the number I want to pay for a old card, or showed me how much I have to pay for a new card.
4) Asked me to swipe bank card, insert cash or coins.
5) Showed me the value of my laundry card now and returned it.
Describe the context in which it’s being used
It's in the mailbox area at the first floor of the building. It's quiet and clean. When residents in this building need to buy a new laundry card or to add value to their old card, they will go downstairs and use this machine. Rare people use it and there is definitely no one hurry you when you do it.
How people use it, what they do differently
I was waiting there and met one people tried to buy a new card. She looked the machine for a long time, holding her purse, searching the first thing she need to do. After she found the instruction on the small screen over the keyboard, she was confused about where was the button and which was the correct one among these three purple button. Then she pressed the right one, swiped her credit card, looked at the screen again, waited for few seconds, took out the output laundry card and receipt. After that she still checked the screen for a while, then left.
what appear to be the difficulties and takes the longest
Finding out "the first step" instruction seems difficult and takes the longest.
What appear to be the easiest parts and takes the least amount of time
Swiping credit card and taking out the laundry card and receipt are easy and spend lease time.
How long the whole transaction takes
Almost 1 minute.
How the readings from Norman and Crawford reflect on what you see
The interface of this machine is not a good design. Even it has the affordance of input, output and card swiping, which make some parts of the process easier, its instruction is barely visible because it appears on the unexpected small screen. Also, the mapping of button and indicator is worse, since there is a relatively long distance between them. The whole keyboard attract user's most attention, however it has the least function in the whole process. All these design confuse user and lower the effectiveness of interaction.