On Tuesday 14 June 2005 04:21 pm, Olin Lathrop scribbled:
> PicDude wrote:
> >> So how fast are you updating the display?
> >
> > IIRC about 4-5 times a second.
>

First a correction.  Since posting that, I measured it and it seems to be 
about 3.5-4 times per second.


> Why so fast?  It takes a certain amount of time to see a bunch of blinky
> lights, recognize them as a number, comprehend that number, then do
> something with the information.  If you go too fast, you annoy people that
> the number changed before they had fully internalized the previous one.  I
> think 5Hz is probably over that limit or at least near it.  Take a look at
> a normal digital voltmeter.  I think you'll find the update rate is more
> like 2-3Hz.  I'm sure Fluke and other put some thought into this.  Why not
> just do what they did?  If your display bounced between adjacent numbers
> every 500mS, I doubt it would be all that annoying.

Yes and no.  The display output goes to both a numerical output and a bargraph 
(24 leds).  The bargraph output looks really sluggish if slowed down more, 
but you're correct that the numerical output gets jumpy.  So far though, with 
the filtering, the numerical output is not that bad/annoying for quick 
changes when it is following a trend and going towards one direction.  But 
the digit toggling is a royal pain.

I can probably guess what you are thinking now, and I have been fearing doing 
that -- ie: using independent IIR filters for the bargraph and numerical 
outputs.  :-(

Cheers,
-Neil.





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