The machine requires its user to maintain it routinely by running it through a cleaning cycle. During the cleaning cycle, the user must interact with the machine by pushing the start button, adding cleaning tablets, filling a water tank, and emptying and replacing a water receptacle.
To run this part of the session, we had three versions of the physical prototype set up in the lab. Because the physical prototypes were not entirely illustrative of the process, we also had an on-screen Invision demonstration of the cleaning process that had been used in prior testing. Participants were asked to engage in the cleaning process, and it quickly became apparent that they were unclear where and when they needed to interact with the machine, what the process entailed, and when the cycle would be complete.