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114 Making Things Move

So, how do we use capacitors? The easiest way to integrate these into your alternative
energy projects is through ready-made modules called charge controllers or
energy-harvesting modules. These modules take unsteady power, like that from a
solar panel or a hand crank on a flashlight, and use it to charge a battery or capacitor
that releases the power in a steady way that looks smooth and consistent to motors.
Part 585-EH300A from Mouser Electronics (www.mouser.com) is one such module
that can filter unsteady input energy and release it between 1.8V and 3.6V with up to
1A of current for a very short time. 5

If you have a motor you want to power continuously, you probably want to set up a
circuit that allows your alternative energy source to charge a battery through a charge
controller like the one shown in Figure 5-10, and then run your motor off the smooth
battery power through the charge controller. See the section on decoupling capacitors
in Chapter 6 and the Wind Lantern Project 10-2 for more ways to use capacitors.

FIGURE 5-10 A solar charge controller like the one shown (from Silicon Solar) allows you to
charge a battery through solar panels, and then run your motor off the battery. This model is
used in the SADbot project (Project 10-3).