Ed,
Here is a first cut on the pc board. I can step and repeat
this to cut the cost per pc board greatly.

What dimmer switch are you using so I can finish it?

Paul Lamar

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 Paul,
    Any SPST switch will work.  I happend to use on of the Micromini Toggle
switches I had from Radio shack.  Threw away the wrapper so don't have the
part number handy.  When the switch is open the 1000 ohm resistor drops the
voltage and dims the LEDs, when closed it shunts the 1000 ohm resistor and
provides full 12V to the LEDS.

Also your layout for the potentiometers R3 and R4 may need to be changed
slightly.  I used the Radio Shack Cermet Pot with adjustment screw it is
shaped like a rectangular box with an adjustment screw at the small
end.However, I see no reason that one of their Micro-size Pie shaped pots
would not work as well although the screw adjustment is not as fine a
resolution as the Cermet Pot. In both cases the 3 points are for connection
are not in-line.  The Pot take-0ff connection (wiper) is the center
connector and is off-set one row to the right looking at the end with the
adjustment screw.  I alined mine so that the adjustment screw end point to
the side of the board whereby I drill small holes in the container box so I
could adjust them without taking the board out of the box.  However, once
adjusted on the bench it probably would not require any further adjustment..

   In any case, I've attached the dimensions for the Pot I used (Cermet Pot,
blue Rectangel) as I find the 15 turn screw adjustment provides better
control when tuning the voltages.

Ed

OK on the switch. I think I will use a low profile slide switch a little taller
than the LED bar graphs so it will stick through the instrument panel.

Will these pots work Ed? I got a bunch of them and they seem to be available
in all qualities up to $15 each from DigiKey. I like the 3299W. It takes up
a minimum of PC board real estate and can be adjucted from the top.


Paul Lamar
 
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