For those who want their rig to look good, there are always some eye-candies available on the market. I've seen on the forums several members asking about ways to mod the Hard Disk Drive Led indicator. There is not much we can do with just this led, except if we're to go with a pre-modded commercial item like the $40 MojoMeter.
Now for those who are a little more hard-core, the DIY style HDD meter is for you. This guide has 2 different sections: analogic meter and digital meter. Both uses the same principle: taking the signal from the HDD Led indicator and having a scale of its on/off ratio showed visually.
First model: Analogic (needle) HDD meter
I came up with the needle HDD meter after having someone here at GTF seeking for some kind of geiger counter for his hard disk. It's pretty simple how it works, and how it's done. Here's what you need:
- VU-Meter of some sort (the cheaper the better)
- Rheostat or Potentiometer (around 10K ohms - to tune the values)
- One resistor (value depends on your VU-meter)
- Wires
- Connector to your HDD indicator header
- Heat-Shrink (for a better looking soldering job)
Tools needed:
- External power supply (for testing and tuning)
- Soldering iron
- Multimeter
Before we do anything, let's figure what is a VU-Meter. Analogic VU-Meter is usually the old "Volume Unit" (VU) Indicator that are found in old sound systems. It is mostly a coil on which there is a needle. As more current passes to the coil, the needle jumps higher. These can be found on a lot of old audio equipment at local surplus stores. There are also some products that have the same needle indicator, such as battery testers.
I looked for a cheap one at hardware and electronic shops. The cheapest were at surplus stores, but an easy-to-get and not-so-expansive version was the battery tester at the local Radio Shack. The battery tester, same as VU-meter, have low voltage capabilities, which is great for us as there is no need to isolate the meter from the motherboard's HDD connector.
Since the battery testor is at max power of 1.5V, we want to place a resistor on it to reduce the voltage. The meter I got was torn from a commercial device, so there is no specs for it, therefore we'll have to tweak the values manually. How I proceeded was by putting a potentiometer in series with the meter, and plugging that to the 5V molex of my external AT power supply. Before powering this, I made a lecture on my pot to ensure the resistor value is at max to avoid burning the meter.
