@Templar nice ideas, there are all sorts of effects you could do along those lines. Maybe when the pot position is changed (ie you detect a different level with the ADC) the leds could go wild for a while (rotating patterns etc) for a few seconds, then settle down to indicate the level. The more complex the changes the better :-)
You stated in your article that the potentiameter that you're using only has 300 degrees of rotation. The limited rotation would then prevent you from lighting 3 of the LEDs on the front panel. Since the NeoPixel LEDs that you're going to be using are individually addressable would it make sense to equate the potentiameter position to the number of LEDs that would light up?
Using a ring of 20 LEDs and a 300 degree potentiameter one LED could be lit for every 15 degrees of pot rotation. The trick here would be placing the output of the potentiameter on a ADC circuit (some examples can be found in the Rasberry Pi community) which in turn would feed the LED controller. With that working not only would you be able to light all 20 LEDs, but you could also assign different effects to potentiameter position. Say every 10% increase in pot rotation changes the brightness level, or above a certain pot range the LEDs begin a "breathing" routine. One could even set the LEDs to "count" in binary. With each LED representing a bit the ADC output could be used to light LEDs as follows:
With one equal to on - 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000...
@Stargzr: They were often used as a visual indicator of signal strength when tuning in a station on old radios.
They do look really tasty -- I don;t think I can add them to the main panel, because that's pretty much in the final stages of layout, and I don;t want to incure the "Wrath of Willy" (the guy who is kindly creating the 3D CAD drawings for me) ... but maybe for the Male Engine ... this could form the main display -- the big green dot in the lower-middle of the panel on the upper box (click here to see what I'm talking about).
Really? Max, you're showing your youth! I've only seen a couple in real life, but I think I have one "somewhere in the basement." They were often used as a visual indicator of signal strength when tuning in a station on old radios. Later we had meters, then bouncing Vacuum Fluorescent Displays, and now we have bouncing LEDs or LCDs.
@Samuel: As for the colors and effects, maybe you can use blinking at different speeds to further differentiate the states. So the LED blinks faster until your turn the pot enough to fully turn it on.
Good idea -- in fact I'm also going to do some of that with regard to the LEDs lighting the vacuum tubes -- there's going to be some sort of proximity sensing capability -- when someone approaches the engine, the LEDs will respond in some way -- possibly by cycling faster.
@Samuel: I like the idea of it being slightly unpredictable, so why limit yourself to showing the status of the potentiometer itself?
I think I've got a bit of this in that -- once you've set up the initial conditions/values for your inamorata -- if she changes one of the motorized potentiometers -- after a few seconds the others will adjust their values to compensate. But I will ponde ryour ideas -- th egreat thing about thsi engine is that it's all under software control, so we can try a variety of different algorithms.
I like the idea of it being slightly unpredictable, so why limit yourself to showing the status of the potentiometer itself? You could show the 'true' value of whatever you're adjusting instead. So for example when the 2nd potentiometer shows 3 green lights, the 1st works normal, but if it shows 4 or more then the true value of the 1st is multiplied by 1.5, but for every 3 LEDs you move it the 2nd potentiometer loses an LED (but doesn't move the pot, if it's 6+, then the pot gets moved but the LEDs stay the same). With the acceleration (or deceleration) effects you can also use the bottom 3.
As for the colors and effects, maybe you can use blinking at different speeds to further differentiate the states. So the LED blinks faster until your turn the pot enough to fully turn it on.