Easiest way to connect an arduino uno to my computer's PSU to control ARGB lighting

Full disclaimer: I know VERY little about electronics and electrical components. I understand the bare basics of electricity as a concept, but my background is more focused on programming/software development. In other words, if you throw a bunch of electrical engineering jargon at me, it will likely go over my head. Thank you in advance.

I recently purchased 6 Cooler Master Sickleflow 120 ARGB fans for my computer case. After installing, I realized that the RGB control software available was very limited and I wanting to have a wide array of programmable options. So I grabbed my trusty arduino uno, found some simple tutorials online, tweaked some code, and created a functioning RGB light show in my computer case (it looks amazing). The next step in this mini project is to integrate the arduino into my case. Currently, the arduino is powered by my computer via USB, but I would like to have it draw power from either my computer's PSU or my motherboard. This will make cable management less bad and free up a USB port. What is the easiest way to do this? Is there an adapter that I can buy to plug into my PSU to power my arduino? As mentioned, another option might be to draw power from my motherboard to my arduino somehow. Ultimately, the goal is to power my arduino when my computer is turned on in the safest and least dramatic way possible.
My motherboard is a MSI B450 Gaming Pro Carbon Max WiFi and my power supply is a Thermaltake Toughpower Grand Series RGB 750W (modular). If any other specs are needed, I will gladly provide them.
Thank you!

I'll never understand the obsession with lights inside the computer tower.
Do you have any unused cables from the PSU? You could easily cut the end of the cable and then find the 5V and ground wires. That, however, would require soldering.

I don't understand that either.

Why? Your motherboard has 12 USB ports. I would prefer to use an internal USB port as the most convenient - so very easily you can reprogram the Arduino if necessary. This way you will even be able to create different lighting effects depending on the CPU load, the GPU load and / or their temperatures.

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Thanks for the reply. I currently have an extra USB port on the back of my motherboard I could utilize, which would leave me with 4 usable USB ports that are built into my case. There is a chance I will want to change up the lighting someday, so powering via USB isn't a terrible idea. I think I'll give that a go. Thanks for the advice.

As for "the obsession with lights inside the computer tower", the reason is because it looks really amazing, especially when you choose something other than a rainbow or a static color. Also obsessive consumerism...

Any PC power supply has a 5V rail - yours seems to be able to supply 22A, so you can power your Uno from that if you like. Depending on how comfortable you are with the wiring, you may decide that the spare USB port is easier.

I looked at your power supply. If you are comfortable with wiring and do not want to use a USB port, in my opinion the easiest and most trouble-free is to get a 5V power supply for Arduino from the FDD cable. I guess your computer is new and hardly has a FDD at all.

I would not cut the connector off the power supply. As was mentioned, there may be a power cable for the FDD (floppy disk drive), if not then if there are any unused hard drive power connectors, get an inexpensive extender or adapter cable to plug into one of those and cut the free end off that cable.

Amen to that! :+1:

Generally will be on a "generic" PSU as used in the sort of cases that one puts lights in. :grin:

And this connector is in fact, 0.1" spacing compatible with "Dupont" pins.

Proper way to do it. Again, a "custom" supply will have extra connectors, if not you can get "double adapter" cables and modify those.

That PSU is all modular. There's no wires coming out of the box to cut.

So by definition, it comes with a set of cables - about nine by the look of it.

Presumably you can purchase additional cables as needed if you hack one up. :grin:

Be careful if you do this that the cables are from the same manufacturer - they have a bad habit of making them proprietary.