I had initially hoped that the Rasberry Possum photo backup system could have used just one power pack. I found a "Y" adapter on Amazon that I thought would enable both the Pi and the hard drive to power power up from one adapter, thus enabling the use of an un-powered hub. Unfortunately this was not to be, as the Pi seemed to occasionally reboot in this configuration. We were getting down to the wire on this project, with only two days before our trip to Asia. The next best solution was a to use a powered hub for the hard drive, leaving a dedicated power source for the Pi. The diminutive Belkin F4U040 looked like a great solution. It's very compact, but were the power specs listed anywhere on the box; or on the Belkin website? No. I took a chance and bought one anyway, and was relieved that it was good for 100-240V - a true world power supply. To power the Pi I used an Amazon basics 2.1 A power pack.
Here's the interconnect diagram.
And here's the Possum after backing up photos from an iPhone at Sun Moon Lake in Taiwan. We're using the iPad to telnet into the Pi to verify the that all the photos have been copied.
The Possum can also be managed from an iPod. I used Eric Maland's pTerm which worked very well. Also, we found that the ad-hoc network connection was very tenuous, so to keep it alive I used MochaSoft's Network Ping Lite.
