You thought that the Ultimate Reset Button was exaggeration. You thought that the Cheapest Wireless Desktop was not cheap and was a joke. You even thought that bunnies try to commit suicide. And you were right! Now wait till you see this!

It’s not revolutionary and it’s not something that doesn’t work. It is also not something that you can save bunnies with. And it’s definitely not a joke! It actually works as it’s supposed to. Yeehaaw! It’s another computer mod with which you will be The Man at LAN parties. You can even drive other geeks mad with this device…or cause them temporary blindness. Interested?

First, there were plain ordinary red LEDs to show you the HDD activity. There’s nothing special about it – a boring red LED that flashes irregularly. Time to change that in a mad scientist way: here’s a video of the insane LEDs at work:

Unfortunately, my IDE controller decided to go into early retirement the day after this video was taken (and no, it has nothing to do with this device…second hard drive stopped working and the controller with it). Go figure…

Circuit is very simple and uses only 11 parts of which 10 are LEDs in the color of your choice (we used 5x white and 5x blue). The “brain” is a HCF4017 (CD4017, etc.) IC which is a decade counter. Schematic is here:

As you can see for yourself, wiring is extremely simple and entire circuit can be assembled without the printed circuit board. That’s why you won’t find a PCB layout here, at least not from us. There are no current limiting resistors for LEDs because the IC limits the output current but make sure that you connect the LEDs correctly or else they won’t work. Here’s a photo of the test circuit on a protoboard:

(ignore the crystal oscillator and the wires to the right - they are from another project and I was lazy to remove them)

How it works ?

As said before, HCF4017 is a decade counter IC with 10 decoded outputs. This counter is advanced one count at positive clock signal which means that every time a HDD is accessed, another LED lights up in the “running lights” effect fashion. However, you can achieve random looking effect by either connecting or placing the LEDs differently (i.e. LED1 to output 6, LED2 to output 9, etc.).

Connecting it

You can get the required 5V supply from the power cable that goes to CD / DVD / HDD / floppy. Red wire is 5V, yellow wire is 12V and black wires are ground. If you don’t feel like messing with factory wiring, then buy a power Y-cable, cut off the male power connector (leaving wires at least 1″ long) and connect the circuit to that connector. If you are like us, then peel of the wire insulation a bit (0.1″ is enough) and twist the wires together like this:

As for the HDD activity wire, use the one that goes to the original HDD LED. If it doesn’t work on one wire it will work on another one (the test circuit actually worked fine with both wires, but the original LED was left connected!).

Don’t forget to isolate all connections with a tape!

Use your imagination for placing the LEDs. I will drill a few holes (arranged in a circle) on the cover of empty 5,25” bay and hot-glue them so that they don’t run away.

And for the end…

…if it doesn’t work, it’s not our fault! If you somehow manage to blow up your PC, it’s not our fault. Whatever goes wrong, it’s not our fault so don’t even think on blaming us! We accept no responsibility whatsoever. You do this on your own risk.

Feel free to ask any questions! You can also send us your pictures of a working circuit and we will gladly put them here.

Happy modding!