[simpits-tech] Circuit question - plus another for Gene

[Brian Sikkema]

>Looking for clarification...
No problemo. :)

>1. Are all leds the same color (or at least match the
>same voltage drop - diff colors have different drops
>usually)?
Could go either way. If it would significantly simplify things to have all one color, I'll do all one color.


>2. What are you trying to emulate? i.e. Why does it
>need to be one led at a time rather than a progress
>bar style?
It's going to be for a car, the gearshift indicator on the dash. I.e. Park, Neutral, Overdrive, Drive, etc.


>3. What is the power source availability (9v from
>battery, 12vdc from wall transformer, how much current
>overhead do you have?)
12V, current should be plenty for whatever is needed.

>4. What is your budget for the circuit?
Meh. Dunno really. This is a project for "sometime down the road" anyway. Since this is just a small part of the overall project 
I don't think too much, but no hard number for that one.

>5. Just for you or are you considering manufacturing
>these?
Just for me right now, but the possibility of making more has occured to me... Would depend on the kind of demand I could drum 
up. If I get mine done and other people like the look, I may definitely look at making more for fun and profit. ;)

>Btw, there exists an "audio taper" version of slider
>pots which is non-linear; they are parabolic in gain
>meaning that you get a very similar characteristic to
>what you describe...having to come up to 33-50% to
>achieve initial threshold and most of its operating
>range is on the high side. These are the pots used in
>soundboards. They are higher priced but designed for
>heavy duty use...here is a reference
><www.bourns.com/pdfs/gapno_panel_controls_taper.pdf>
Yeah I had thought of this, but I don't think an audio taper would work in this instance.


>You are looking for a true slider pot and not a
>rotational, right? The ref above is for rotational but
>they make them in the other form as well. I only
>mention this for your reference not that it is
>necessarily the part of the solution.

Yep definitely a slider. The stock unit has a small cable that comes up from the gearshift which moves the mechanical indicator, 
which is spring-loaded to pull back to the "park" position. Basically my thought is to re-use that stock cable, but hooked to a 
slider to control the LEDs.

Thanks for the help!
Brian