Need Low-Voltage, Low Power Wire Bundle? Use Cat 5e Data Cable!

In addition to USB ports, most PC tower cases also come with a front control panel that connects to the motherboard. This is where the power button, the power LED, and the hard drive activity LED are shown to the user. There is sometimes also a reset button, but they appear to be getting phased out. Personally I haven’t needed a reset button in years and any presses of the reset button in that time has been accidental (and usually instantly regretted.)

Part of building my own PC case is supplying these controls myself. This was part of the fun of building Luggable PC Mark I. For the power button, I wired up a big red button of the type typically used for arcade consoles.

The headers are easy to find, as are the LEDs and their associated current-limiting resistors. The momentary-on push button is also easily found. What gave me headache were the wires for them all. None of them need to carry a high voltage, or a lot of current, but there is a bunch of them and it was a hassle to keep them the same length and not tangled up. Given the hassle and the lack of need, it is obvious why I didn’t put a reset button on Mark I. Without reset, I only had to deal with 6 wires instead of 8.

Thanks to Tux-lab, I’ve learned a much better idea I can apply to Mark II: use a segment of standard networking cable. In my case, I have a spool of Cat 5e I can cut arbitrary lengths from. Cat 5e has 8 wires, enough for the purpose. Even a reset button if I wanted, which I don’t, so the fourth pair of wires were removed.

This is a neat trick, I’ll have to keep it in mind whenever I need low-power, low-voltage wiring bundles in the future.

Control bundle
Freshly soldered bundle, before heat shrink tubing.

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