[sdiy] Retaining button state after power off?

[Magnus Danielson]

On 31/01/14 17:51, Justin Owen wrote:
> Hello,
>
> I have a couple of simple analog circuits that allow you to cycle through 2, 3 or 4 options/outputs/etc using a momentary push switch.
>
> So, for a 2-cycle switch, click 1 is 1, click 2 is 2, click 3 returns back to 1 and so on. For a 4-cycle it's 1,2,3,4,1,2,3,etc.
>
> The circuits output either a high or low state
>
> The problem is that these circuits return to their default state on power off.
>
> What would be the simplest way to write the button state to some sort of non-volatile storage that could be reinstated at start-up?
>
> I'm guessing a micro is going to be the most likely answer - but if there is a non-programming option available it would be great to hear. Failing that - absolute simplest solutions where possible please!

Rotary switches have mechanical memory.

Cheers,
Magnus