“Luggable” power pack

Paul and I are leaving on a cross-country train trip next week, for Jen and Shawn’s wedding in Colorado. I’m sure the view will be great, and I’m bringing a handful of books- but Paul and I are geeks and we need our electro-doodads. If only we had a way to run our Nintendo DS and PSP for the ~30 hours that the trip will take…

I sifted through my stockpile of junk, and came up with this:

It’s kind of like a mega-size Minty Boost, or a heftier version of the Kensington power pack. The Minty Boost weighs in at about 6 Watt-hours, depending on the AA cells you use. The Kensington pack is rated at 7 Watt-hours, with a Lithium Ion battery. This brick occupies the middle-ground between the Minty Boost and a car jump-start battery, weighing in at 84 Watt-hours. It should run and charge a Nintendo DS for at least 30 hours.

It’s built almost entirely from junk that I had lying around the house: (Your house may vary.)

  • 12 Volt 7 AH Lead-calcium battery
  • Aluminum box, in my stockpile of project enclosures
  • Receptacle end from a cigarette lighter extension cable
  • DC-DC converter from an old Nokia phone charger (for a phone I no longer use). Swapped a resistor with a trimmer pot for 5V output.
  • USB sockets from a dead 4-port hub
  • Heavy duty wires and quick-disconnect plugs from a dead UPS
  • Odds and ends: Switch, mounting hardware, fuse holder, wire nuts, foam weather-stripping, JB-Weld epoxy, heat shrink tubing, LED, resistors

Parts I had to buy at the local Fry’s:

  • 10 Amp fuse (Pack of five for a few dollars)
  • 12V 1 Amp lead-acid battery charger ($20)
  • Cigarette lighter plug for the charger ($2)

Now here’s hoping that nobody thinks it’s a “hoax device”…

P.S. I’m still working on the Robot Odyssey DS port and in fact there are some interesting bits of UI working now- but I haven’t quite reached another blog-worthy milestone yet.

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