Good Day:

I have several sets of LED Christmas Lights (on a 50 LED string). I would like to have the LEDs in them randomly twinkle so that at any given moment, some would be steady on and others would be off. By "twinkle," I mean to softly fade in and out, instead of abruptly blinking on and off. Any circuit construction ideas would be very much appreciated. Thank you.

 

Welcome to AAC!

Can't offer any assistance ithout knowing what you have to work with. But my initial impression is that you won't be able to do it because you won't have the ability to control individual LEDs.

 

Good Day:

I have several sets of LED Christmas Lights (on a 50 LED string). I would like to have the LEDs in them randomly twinkle so that at any given moment, some would be steady on and others would be off. By "twinkle," I mean to softly fade in and out, instead of abruptly blinking on and off. Any circuit construction ideas would be very much appreciated. Thank you.

https://www.doityourselfchristmas.com/wiki/index.php?title=Renard_SS24_Controller_Board

If you just want to buy the kit:
http://www.renard-plus.com/renardplus8.html

 

Best way to do "random" is to make each light it's own little oscillator / blinker.

The will drift randomly in and out of sync with each other and look rather pleasing.

When you first turn it on, they will be in sync, but depending on how accurate they are, in time they will drift apart.

 

I have several sets of LED Christmas Lights (on a 50 LED string).

You're pretty much out of luck from the start unless those strings already support different functions for different parts of the string. For instance I have a string that has a controller that can do a lot of that stuff, but that only works because the string has multiple conductors. It's essentially several strings in one.

And by the way, my wife hates ALL the patterns and just wants the lights full on or off all the time.

 

LED's that simply flash, i.e., don't need a separate oscillator circuit, are available. You might be able to build your own string or replace some (say every third) in your current strings. Without more information, we cannot be more detailed.

Here is a link to just one such supplier: https://lighthouseleds.com/led-component-lighting/animated-leds-flashing-blinking.html

 

Put a fast fading LED with flicker in series with a flashing LED in series with a white LED on 12v and you will see the white LED flicker and flash randomly.