Hard Drive Becomes Hard Drive Activity Light; Stores No Data

A while ago [Frank Zhao] built a computer in an aquarium. It’s exactly what you would expect – a bunch of parts stuffed into a container filled with mineral oil. Yes, there’s an i7 and a GTX970 in there, but there’s also a bunch of neopixels and a neat little bubbling treasure chest. That wasn’t enough for [Frank], and he wanted to add a HDD activity monitor. What’s the most absurd activity monitor for an SSD? An old platter-based drive, of course.

The build is relatively simple and something [Frank] put together from spare parts in a day. After cracking open an old PATA hard drive, the voice coil for the hard drive arm was connected to the motherboard’s HDD activity signal through a few MOSFETs. The platter motor is controlled by an MTD6501 motor driver, set to spin up when the circuit is on.

It’s a kludge as far as controlling the components of a hard drive go, but that’s not really the point. It’s just a neat project to show when the SSD in the aquarium computer is being accessed. That said, the activity monitor is currently disconnected because the old HDD is so freakin’ loud. It looks really cool, though.

20 thoughts on “Hard Drive Becomes Hard Drive Activity Light; Stores No Data

  1. Since when is an actuator coil a voice coil? I have seen this before and don’t understand, a voice coil is the coil of wire wrapped around a cylindrical form with a magnet in the center and a diaphragm attached to the form in a loudspeaker. It is called a voice coil for a reason – it is designed to make sound, how does this relate to a hard disk drive actuator?

    1. Also the 70’s and and 80’s vintage mainframe storage hard drives that ran on 480V used a voice coil to position the heads. How do I know? I have one in my garage… it’s about 4 inched in diameter, and if you whack it with 12v it will launch the coil out of the magnet to about 6 ft! Fun stuff!

    1. Actually the part that made me double-take was the CPU heatsink with fan -still attached- that appears both submerged in oil and also wired to power on the MB. Submerging moving parts is a big no-no.

    2. I have done weeks of researching before undertaking my mineral oil PC build, I have never heard of any issues related to PCBs delaminating at all. Can you provide some citations?

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