I'm planning a 19" rack enclosure which will house two SATA drives connected to a Firewire/USB to SATA bridge board. The two drives will be used for two completely different purposes, so I see no reason to have to power them both up at once, wearing them out unnecessarily. That's why I'm suggested 3 switches for the front panel of the enclosure:
- main power switch (gives power to the bridge board)
- drive A power (turns on drive A)
- drive B power (turns on drive B)
The main power switch would be an AC switch which would give power to the power supply. A rocker switch (with a built-in LED) would be fine for this.
For the drives I was first thinking of a high amperage switch (as I've been told that hard drives involve a lot of current) for each of them. The problem with this is that most switches like that are pretty big and bulky and appearance-wise that's not good. So the next solution would perhaps be a "soft switch" solution where I'd be using a small and elegant tacticle switch or something, which in turn would control a relay for the actual on/off power switching for the drive in question. I would probably need some sort of electronic circuitry for this, which would turn the relay on when pressed the first time, and off when pressed the second time. I assume the best solution would be to have nothing happen when I first turn on the AC switch, but that would mean having to press it every time, even if the drive had previously been turned on the last time I used it (unless some sort of memory circuit could be constructed).
A third solution (also involving relays) could be having locking two-position switches. That way I could just leave the drive A or B switches in whichever position I wanted.
I see that the SATA power connector is pretty complex. Which pin(s) would I need to switch on/off through the relay in order to safely have it turned on or off?