Lunetta designs

[electri-fire]

I soldered in 8 patchable LED's tonight with in's and out's. Ok, that works, BUT...(some observations the Lunetta user may recognize):

The slower oscillators have a "Master Clock" feel to them, and the faster ones do pitch like stuff. I tend to use some outputs more often than others.

So LED's could be hardwired to (selected) outputs for faster patching. But as the direction of the LED makes a difference as well I could use two LED's per output. Hrmm, that gets complicated again... maybe I'll just do that on 2 or 3 slower divisions from the 4040's.

Just brainstorming in public, sorry...

[droffset]

You could also try making custom patch wires with an LED in the middle and each side splits to however many in/out as you need.

Post some sound!

[electri-fire]

Warning: Totally off thread whining .

[rich decibels]

Hey there electri-fire, thanks for your stacks of helpful schems. Last night I found the quickest, dirtiest possible way to record sound from my circuits. Attach a couple of feet of cable between a stereo jack and a piezo disk. Plug the jack into your PC's mic input, and lay the cable across your lap. Touch the output wire of your circuit with a finger and it will induce a surprisingly loud and clear signal in the wire. I recorded the arpeggiator I was working on to demonstrate the quality.

(Seriously this works great!)

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[electri-fire]

[electri-fire]

And again on my current obsession :

I thougt I was gating with the LED's, put on my "I want to know" hat, and was trying to figure out some truth tables.

These conditions without a LED:

A B
0 0
0 1 *
1 0
1 1

Expected Gate effect with LED

A B
0 0
0 0 *
1 0
1 1

* change

But then, it doesn't sound the way I expected from my theory. Several actions are happening at one.

Pulse Width.

Charge and discharge of the timing capacitor determin wether you get a Hi or a Low. In 40106 PWM schematics diodes are used to influence Pulse With. Suppose

oscillator A is Lo, oscillator B is Hi , current can flow through the LED or diode, so now oscillator B has to charge capacitor A as well.

Imagine more LED's for example from A to other outputs, some reversed polarity, things are getting complicated.

Next, more complicated still: Bleed through

The output B is connected to output A but with reduced voltage, depending on the LED's "diode drop" voltage.

quote:
" It is safe enough to assume 1.7 volts of voltage drop for non-high-brightness red, 1.9 volts for high-brightness, high-efficiency and low-current red, and 2 volts for

orange and yellow, and 2.1 volts for green. Assume 3.4 volts for bright white, bright non-yellowish green, and most blue types. Assume 4.6 volts for 430 nM bright

blue types such as Everbright and Radio Shack."

source: http://www.theledlight.com/LED101.html

LED as light sensor

http://en.wikipedia.org/wiki/LED_circuit

My LED's are in a row, so adjacent LED's might pick up each other. I still have to check that. If this prooves relevant, putting the LED's in a cluster makes optimum

use of the feature. Or putting a shrink tube or something on them reduces it?

Ok, last for now: Slew Rate http://en.wikipedia.org/wiki/Slew_rate

The slew rate represents the maximum rate of change of a signal at any point in a circuit. Diodes reduce Slew Rate.

I can affirm this is happening indeed, as I recognise the LED sound. Cheap old fashioned Red LED's sound best. Green and Yellow are ok. High-brightness LED's

have less of that fat warm growl.


Some future edits expected

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[ezekiel]

Thanks electri-fire and droffset for the LED "gating" idea. It is providing no end to my lunetta entertainment on the breadboard. Nothing so far has burned up while I was putting LEDs between any random CMOS pins. So far.

Now, the big question, which electri-fire was delving into: What exactly are the LEDs doing? I guess they are mixing and gating and shorting? Can an electronics expert offer a more official explanation that might help us take the next step up towards more intentional, more complex use of LEDs?

The sound makes me think that I've tapped into an alien world.

By the way, I am running my 4000-series CMOS chips on a 9V battery but I see 5V recommended in the documentation. Is 5V better?

Thanks also to dgtom for the 4066-switched-capacitor idea which looks like fertile ground for more experimenting, too.

Maybe we can make a synth from just LEDs and capacitors? Plus a 40106 oscillator.

[electri-fire]

[euhero987]