On Fri, May 21, 2010 at 5:31 PM, Don <d...@blacksun.org> wrote: > Oh I wasn't kidding when I said I was going to have to try this with my home > server. I actually do some circuit board design and this would be an amusing > project. All you probably need is 5v- I'll look into it.
The SATA power connector supplies 3.3, 5 and 12v. A "complete" solution will have all three. Most drives use just the 5v, so you can probably ignore 3.3v and 12v. You'll need to use a step up DC-DC converter and be able to supply ~ 100mA at 5v. (I can't find any specific numbers on power consumption. Intel claims 75mW - 150mW for the X25-M. USB is rated at 500mA at 5v, and all drives that I've seen can run in an un-powered USB case.) It's actually easier/cheaper to use a LiPoly battery & charger and get a few minutes of power than to use an ultracap for a few seconds of power. Most ultracaps are ~ 2.5v and LiPoly is 3.7v, so you'll need a step up converter in either case. If you're supplying more than one voltage, you should use a microcontroller to shut off all the charge pumps at once when the battery / ultracap runs low. If you're only supplying 5V, it doesn't matter. Cost for a 5v only system should be $30 - $35 in one-off prototype-ready components with a 1100mAH battery (using prices from Sparkfun.com), plus the cost for an enclosure, etc. A larger buy, a custom PCB, and a smaller battery would probably reduce the cost 20-50%. -B -- Brandon High : bh...@freaks.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
