OK, I've had a play around with this and the one i posted works ok with a 100k or 47k scaling resistor, but the taper is not ideal.
A simpler way that works better is the voltage divider arrangement shown below, not a bad sweep even with the log 250K I'm using and the LED goes from off to quite bright over the whole sweep.
However, it occurs to me that the brightness of an LED is not a very useful indicator of the pot position, since your eyes/brain quickly get accustomed to the brightness of the LED in one "position" and you will soon be unsure whether it can go any brighter, and the only way to tell is to turn it up, rendering the visual indication pretty pointless.
A much better visual indicator is to use a bicolour LED, or a three colour RBG CA (red/blue/green, common anode) LED, as shown below.
RBG CA LEDs have a single common anode (positive terminal) and three separate cathodes (ground connections): I used the 250k pot to "pan" between them using the outputs of the green and red portion only. At minimum, the green is lit, this fades toward the centre, and the red slowly lights up and gets brighter. You would probably want to tinker with the scaling resistors to match the colour variation to the volume increase to your taste. This is all done very easily in a few minutes if you have a breadboard - I'd advise getting one (if you don't already have one) if there is even a small chance you might want to continue building more pedals.
A red/green bicolour (which usually have a common cathode) might work even better, since these can go from green to yellow (red+green) to red as you turn the pot, but I've run out so couldn't try it.
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mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.
- For this message the author Nocentelli has received thanks:
- Wezly (20 Jul 2014, 22:03)