How do I control single pre colored leds the cheapest?

Communities DIY Corner
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So I have a computer build I’m going for that has a space theme, I’ve drilled holes in the side of the case to accept leds, but the hard part is apparently controlling these things. I could use static voltages, but I’d like them to twinkle randomly, I’m not able to get any system running for 11 or 12 single leds without being pointed to a pi or arduino or something, I’m not sure if that is the way to go with this, but I would like some advice if I could avoid using something more complicated

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You should take a look at those old christmas tree circuits using something like CD4026/CD4017 counters.

You’ll need two counters for your outputs and probably some type of clock source (like an NE555) to control the speed. This will make them blink but you’ll need an appropriate capacitor for each LED to add a voltage decay and make it fade in/out.

Depending on your soldering skills (and what parts you have lying aroud) this can be an afternoon project if you have a schematic.

If you want to fade in/out 11 LEDs with an arduino you will need extra components since you will run out of PWM channels.

Edit 1: If you actually manage to build the analog version you could use the PWM signal from your CPU as a clock source and the rate of blinking would then be temperature dependent.

Take a look at this circuit which uses the 4017 that can power 10 LEDs: https://www.instructables.com/Christmas-Tree-With-555-Timer-and-CD4017-Decade-Co/

Edit 2: Typo in part number

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I’d actually recommend the Arduino or the RPi Pico uController platforms. Easy programming, truly randomised blinking, powered and programmed via an internal USB header, if you must. And the RPi Pico is available in wireless versions too.

https://www.raspberrypi.com/products/raspberry-pi-pico/

HTH!

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I’m not sure if this will create the same effect that you want, but I thought about this video:

His design uses simple flashing LEDs that are all wired in parallel, and will gradually desync from each other creating random patterns.

It’s also easy to implement, since you can just tap into the 5V or 12V PSU rail and add an appropriate resistor for each LED in your chain.

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My first electronics lab project was a 10 channel chaser using a 555 + 4017 and TRIACs. Very easy chips to understand the use of and build a circuit from. Maybe not as random as you will want.