Using left, right, select buttons for up/down navigation?

Question

I am currently designing a product which has an lcd screen and three physical buttons that allow for navigation: left, right and select. Currently, this lcd is VERY small so I have limited screen space to work with. Given the menu options, currently the navigation allows you to select from a list of options at the bottom of the screen. I am wondering about the implications of using the left/right buttons to implement more menu features, like going up/down (image on the right). As you can see, when you select the left arrow it can go up to select an upper button. Are there any downsides/user errors that can occur from this design? The main one I can think of is that users may get lost navigating since they may be unclear about when the selector goes up/down vs left/right. Is there any other way to implement these buttons for navigation purposes?

Edit: Additional question, if the user is on the far right button and hits the "right" button, what should the user expect to happen?

Answer 1

Make sure users get feedback for every arrow button press. Avoid 'stuck' states.

I don't have hard evidence, but the most important thing here is the feedback users will get.

There's only 2 buttons. The main thing is that the focus states are quite clear. You can do a thick border, perhaps a color tint as well.

The other consideration is that if you keep tapping right for example, you go from left to right on each row, and then down to the following row. When you hit the last item, did you plan on it bringing back up to top left?

This way there's never a stuck state. Since the screen is so small, users will get constant feedback within their direct field of vision.

Answer 2

I think you could do away with the select button and make things simpler and more straightforward by using the space to add the 4 arrows (top, down, left, right) and then let the user select the option directly by tapping on the item they want to select. This way users have more control and can easily return to the previous options, hence covering at least two of Shneidermann's 8 golden rules of UI design:

6. Permit easy reversal of actions.

As much as possible, actions should be reversible. This feature relieves anxiety, since users know that errors can be undone, and encourages exploration of unfamiliar options. The units of reversibility may be a single action, a data-entry task, or a complete group of actions, such as entry of a name-address block.

7. Keep users in control.

Experienced users strongly desire the sense that they are in charge of the interface and that the interface responds to their actions. They don’t want surprises or changes in familiar behavior, and they are annoyed by tedious data-entry sequences, difficulty in obtaining necessary information, and inability to produce their desired result.