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This interface has a few learnability issues, mostly with the home page. The choice to use icons to display the different machine types was meant to reduce the amount of text involved in the interface. However, the icons in the final product (if this design element remains) need to be carefully chosen to be as intuitive as possible. The "water bucket" icon for a washer is pretty reasonable, but the "box with a port hole" icon for a dryer is not. The arrows muddy up the design with needless complexity; perhaps another way could be found to describe the state of the machines.
It is not intuitive that the app would display fewer machines than are in the laundry room; this application does not display any information about dryers that are currently in use. But, displaying useful machines as a fraction of available machines would add extra text and complexity.
Some good points about the learnability of this design are its external consistencies with other Android applications. The app uses the default icons for text Messaging and Phone calls. The user would probably recognize these icons and intuit their functions accordingly. Also, the application displays internal consistency by having the same screen perform multiple functions. The home screen also acts as the display of time remaining, once the user's laundry is in a machine. Also, the interface for reading notes is very similar to the interface for writing them. In order to get the user to recognize the text box for entering their new note, some highlighted default text could be used.
Efficiency
Safety