Minimum interface button count?

Hi there!

Im planing to build a few projects with lcd interfaces where the user can make adjustments to settings.

So far I thought of these buttons for interface navigation:

  1. Ok
  2. Cancel
  3. Up
  4. Down

Do you think these are the minimum button count you need for a simple interface or are there any ideas I havent thought of for even less?

Thanks in advance!

It seems reasonable. I have used an encoder knob/button combo as the interface on projects (so only OK, Up, Down). Having Cancel is not absolutely necessary, but probably nice.

I would think it depends on how complex the interface is.
For my current project I am making an interface using a single button.

Short press = choose
Long press = scroll through menu
double press = cancel/back up

A lot depends on the feedback available to the user. If there is a screen that makes it clear to the user how his keypress has been interpreted then complex use of keys can be OK - e.g. long, short or double-clicks.

But if there is no visual feedback it will be important to design the system so that the user is not confused by things happening that s/he was not expecting.

My own preference would be for single-purpose buttons.

...R

Cool! Thanks for your input! I will test some options.

My 11 year old has an unnamed brand MP3 player. I cannot for the life of me fathom how to navigate it, the function of the buttons changes with each menu screen.

However, she flies through it using only two buttons, which at any one time could be:

Select
Cancel
Up
Down
Left
Right
Forwards
Backwards
Volume Up (I have yet to witness a "Volume Down", presumably there is one?)
Top
Bottom
Strange
Charmed

I'm fairly sure the mass of the MP3 player changes depending on what button is pressed too...

I would agree with Robin2 - dedicated buttons make people less angry. But as a minimum, having just down and select would be workable, so long as the menu scrolled on a loop, and cancel was on a timeout after a few seconds.

You can use LiquidMenu Library.

Here is the example with 3 buttons