Hello everyone! Long time reader, first time poster here.

Recently decided to make my own dive into development of HDD clicker of some sort, as it's probably the easiest way I can get one for myself, even though there are several options available for purchase online. So well, now there are a couple more to choose from:D And, perhaps most importantly, you can build it yourself!

I made my own take on the theme with progressive iterative approach in mind. Each iteration can be built using the cheapeast available electronic components on a small breadboard (no soldering required, unless you whant to). Schematics and easy-to-replicate breadboard views are available for all versions. There is also a PCB version of the most advanced variant (MARK-03), with GERBER and SVG files (for professional and DIY manufacturing respectively) available on GitHub: https://github.com/Spirik/HDDc .

Video demonstration of each option are available on YouTube, including a demonstration of the sound adjustment on the most advanced version (MARK-03). Quake timedemo and Speedsys Hard Drive Fast Test from Phil's Computer Lab DOS Benchmark Pack were used as scenarios to create realistic load on the hard drive.

Since all the details and downloads are available on GitHub, I will only list the key points regarding each option here.

• MARK-00 (video timestamp: 00:06)
  Piezo buzzer connects to HDD activity LED output of motherboard directly. The simplest but quietest option. And not enough similar to a real hard drive.
• MARK-01 (video timestamp: 01:16)
  Power piezo buzzer with +5V from PSU via NPN transistor. Significantly louder option. But still, it doesn't sound much like the real deal a lot of the time.
• MARK-02 (video timestamp: 02:24)
  Power piezo buzzer with +5V from PSU via optocoupler. Similar to previous option but with galvanic isolation from motherboard HDD LED output.
• MARK-03, Breadboard version (video timestamp: 03:34)
  Add multivibrator IC to adjust duration of pulses sent to piezo buzzer. Features more "clicky" and adjustable sound.
• MARK-03, PCB version (video timestamp: 05:08)
  PCB version of the previous option.

The most plausible option from the list above is by far MARK-03. PCB version of it fits all of the components in a 41.9x41.9mm footprint with mounting holes (on the bottom edge of PCB) aligned with mounting holes of a typical 3.5" drive cage. Watch this video segment (timestamp: 06:19) to see a demonstration of real-time sound adjustment. An optional enclosure to house the PCB has also been designed. The one shown in the photos is laser-cut from 1.3mm-thick acrylic and is assembled using a set of M2 nylon screws and standoffs of varying lengths.

This was a fun side project for me. I hope it will be interesting and useful for someone else too!

Cheers.