As some of you know, I’ve recently traveled to Boston for the ESC/Design East conference. While that was fun, what quickly became a problem was my phone’s limited battery life. I’d leave in the morning with full charge, and by about 4PM each day it’d be asking for a charger. Normally it’s not a problem, except when you are in a new city and relying on your phone as a your navigation aid. There are obviously commercial solutions- a spare battery or a rechargeable battery pack or theOSHW ones such as Adafruit’s MintyBoost.  MintyBoost was the closest to what I was looking for, but still not quite it. So I set out to make my own. Continue reading →