Re: Digital potmeter with on/off switch?

Joerg wrote:

Hello Frank,


Currently there is no uC, it's just for a few demo models. I am afraid
I'll have to cook up some logic like usual. I wonder why there is no
product for the typical scenario: Dormant upon power-up, wiper at bottom
and not in the middle like most of them. Hit UP button, unit turns on or
a logic output goes high. Hit UP some more and pot wiper goes upwards.
All that's needed would be a logic output, the rest could be done with
FETs and stuff. Holding the DOWN button long enough would turn it all
off again.

Yes, I see the DS1809 now, that looks okay. Add a 4538 kludge and
you're all done.


It'll still be pretty messy and the pot must start at wiper bottom. Most
of these need 5V or some other logic supply which this circuit doesn't
have unless I add some more parts. But I guess this digipot/logic combo
is the only way.

BTW, the typical scenario is that users search for an on/off
switch. They panic when they can't find such button ;)


Just add ON and OFF to the + and - symbols. Or one of those pictograms
that nobody understands ;-)

The old potmeter + switch worked, because it also gives the
audible click when turned CCW.

Oh, please add the little speaker that plays "tingel di dum" when
powered on, and "ta di da dom" when powered off ;)


And offer the capability to download ringtones. For a fee, of course.
Just got a cell phone. It came with six tones, all of them some weird
music stuff and all IMHO pretty disgusting. I guess kids would like this
metallica stuff. They don't even offer a simple beep in there. Arrrgh.

If at least they had that old Radio Noordzee jingle or the one from
Wolfman Jack.

Regards, Joerg


Joerg, if I'm not mistaken a DalSemi digipot can - but does not necessarily -
remember its setting through a power down/up. Whether wiper posn is saved or
not is decided by the implementer (you, in this case). I think this is the
case; it's been forever since I read the data***.

I think digipots are cool .... for certain applications. Not for others. I
hated the radio that came with my 1986 Saab because it had no knobs at all. The
day after I took delivery, on a trip from NY to Virginia, I found myself playing
dodge-em with evening rush-hour traffic around Washington D.C. while
simultaneously drilling through the ^%$%#! radio menus to get to the treble/bass
controls! The day after I returned home I ripped that sucker out and dropped it
on the dealer's desk.
.