So, let’s say that you’re more of an outdoor type.
Also let’s say that you kinda of geek and like recording things.
For example, recording an path that you walk on through the woods and rebuilding it in an itinerary in Google Earth.
No problem. You have a GPS unit and you have the option (through factory installed software on the GPS unit or through additional funny software put on top of factory installed software) to record the path you go through.
The problem that you’ll hit is that the battery life of the GPS unit is at most 2 hours (we’re talking about a standard cheap unit that you’d normally use for car navigation - nothing too fancy). You see the problem with these units is that they are not really made to work standalone.
So you have 2 options:
- either buy a new (read more expensive) GSP unit with higher autonomy
- build a portable charger for your stinky GPS unit and connect it the unit to give it extended autonomy
Of course I’m not going to suggest that you go buy a new one. That would be rather dumb on my side and would take all the fun of building the portable “charge” on your own.
So armed with this choice, and willing to have fun we go look for USB specifications.
First thing you come across is the Wikipedia page (as expected): http://en.wikipedia.org/wiki/USB
You learn many new things about the USB: types of connector (you need this in order to know what kind of jack your “charger” will need to have), assignment of pins (which are for power and which are for data?), way data is transmitted (you don’t need to know that, at least not at this poject >:) ) and in the final strech you read what you really need: the power specifications: http://en.wikipedia.org/wiki/USB#Power
Here is where a hardcore geek would get busy. As I am not really that hardcore, and I fit more easily into the lazy geeks sections, I didn’t stop at the wikipedia and searched a little further. :)
And found this:
http://www.instructables.com/id/MintyBoost!—Small-battery-powered-USB-charger/
Someone already did it for me. It’s just buying the parts and puting it all together now.
Sweet.