Interface usability testing and prototyping

03Feb08

Zojirushi rice cooker #NS-JCC10

The NS-JCC10 is a Japanese made and designed rice cooker. Overall it is extremely well designed, form and function, and makes a great pot of rice. What sets this cooker apart from the others i’ve used before is its digital interface giving the user multiple options and control based on the type of rice, white or brown for example, as well as softer or harder consistency, and reheat options. The “flaws” lie in the interface and have to do with economy of real estate as most buttons have multiple functions that do not provide adaquite user feedback as to which function or mode has been selected. The interface economy provides an aesthetic quality at the expense of user control and ease. Two more smaller buttons, isolating reset and reheat, would provide a more intuitive interaction without taking up that more place on the interface. In addition, splitting the minutes button into an up and down option would reduce the actions of the user drastically and provide for greater control, since as is, the minute and hour buttons are uni-directional and the minute button moves in 10 min increments. Lastly, an illuminated lcd screen would make for far easier reading regardless that its a rice cooker functioning in a kitchen that will get dirty from its own spewing of starchy liquid as well as other food stuffs around it (see well used cooker bellow).

Buttons:

1. Keep Warm/Reset = KR

2. Cooking/Reheating = CR

3. Timer = T

4. Extended Keep Warm = E

5. Clock = C

6. Hours = H

7. Minutes = M

8. Menu = MU

Notation:

v press
^ release
* repeat task
s- seconds to complete

Task 1:

- set cooker to pre-defined mode “softer” and set to cook

actions 1:

[MU v ^ * 6], [CR v ^] = 7 actions / 6 s

*user 1:

*user2:

Task 2:

- set timer to 30min from current time and set to cook

actions 2:

[T v ^], [H v ^ * 5], [M v ^ * 3], [CR v ^] = 10 actions / 8 s

*user 1:

*user 2:

The main problem observed was the user over shooting their intended time marker and having to press the minute button more times than should have been necessary.  The next problem obversed from useres was the confusion with multiple function buttons as well an icon on the bottom left of the lcd, white/brown, that seems like a menu option, but isn’t – just a useless icon.

here is a paper prototype including my suggestions for improvements that would lead toward greater user ease.

more user videos to come…

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