Hardware Reference
In-Depth Information
method, but hacks are about trying something new. As long as you conduct
your electrical experimentation safely, the worst you'll end up with is the
loss of a $35 board but the gain of a good story, possibly featuring smoke,
which enhances any story.
But if you want portability, what you need is a battery pack. You might think of these
devices as emergency power for your cell phone. They come in assorted strengths,
shapes, sizes, and colors, but in the end, they're two things: power and a USB port,
which are the two things that you need to power the Pi.
Look for one that has 5V regulated output. We use the New Trent iCarrier (IMP120D),
a 12,000 mAh pattery pack with two USB ports and an on/off button. Depending on
activity on the Pi, that's enough power to last 14- 16 hours or more.
This portable power is critical to some of the hacks in this topic, most notably
Hack
#44
. It's an enhancement for others. And worst case, it's spare juice for your phone.
Test Your Might (in Volts)
HACK 19
If you aren't already friends with a multimeter, you will be soon. Pi
projects all need power, and the Pi provides a way for you to check the
voltage of the board on the board.
Assuming you don't have a few power supplies around to swap out, or if you're deter-
mined to get a particular and unusual power source working, you're going to want to
check the voltage on the Raspberry Pi.
There are two test points on your Raspberry Pi for just such a need, as shown in
Figure 1-14
. TP1 is the 5 V point and TP2 is ground.
They're in slightly different but nearby places on the Model A board, but they're
still labeled TP1 and TP2 in that tiny white PCB label text.
