LadyAda sells a pretty neat kit to allow you to give your USB gadgets power from 2 AA batteries. To create the “Boost” (save for batteries) The capacitors, IC Socket, schottky diode, etc.. took roughly 10 minutes to solder onto the PCB using these instructions, and another 15 minutes and 2 Altoids gum tins to give it the “Minty” part. Note: I spent the better part of 2 days locating these gum tins in the midwest. Eventually I found them at CVS of all places.
A couple of test gadgets; iPod touch (Gen2), G1, iPod Shuffle seemed to work just fine. The tin does get hot, and there is a buzzing and hissing noise that emits from the tin. Perfectly Normal.
From the F.A.Q
“How many charges/hours of use can I get out of a MintyBoost?”
This question is hard to judge because every device has different power usage. However, a simple way to calculate approximate run-time is: take the size of the internal Lithium-Ion battery (for example, many iPods have 750mAh batteries) and divide 1000 by that number. So for a 750mA battery, 1000/750 = 1.3. The MintyBoost will fully charge the device about 1.3 times, as a best case. Remember, this is only an approximation and has a lot to do with the quality of the batteries you use (expensive alkalines v. cheap rechargables) and the internal circuitry of the device for recharging the battery.I would suggest this for anyone needing a quick burst of juice on the go. This is also a nice beginners soldiering project.
As always, comment with questions or contact me via twitter.