Hardware Hacking Projects for Geeks

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Many hacks require a portable power source. Batteries are easy to replace

and an inexpensive source of electrical power. Solar cells provide electricity

when exposed to light, and generators are also available. Let’s take a look at

the pros and cons of each.

Batteries

Batteries are probably the easiest portable power source to work with.

Battery capacity is typically measured in amp-hours or milliamp-hours.

This number is the product of the amount of current (in amps or milliamps)

times the number of hours it can operate. For example, if a battery is rated at

1,000 milliamp-hours of capacity, it can deliver 1 milliamp for 1,000 hours

or 100 milliamps for 10 hours.

Disposable

Batteries generally come in two types, rechargeable and nonrechargeable (or

disposable). Both types are available in many different shapes, sizes, volt-

ages, current capacities, and performance characteristics. Let’s first look at

the ones you toss once their power is depleted.

Zinc carbon cells

One of the earliest types of nonrechargeable batteries was the “dry” cell, or

zinc carbon battery. Previous batteries were composed of solid electrodes

(metal rods) immersed in a liquid solution. The dry cell did not require a

liquid solution, hence the name. The invention of the zinc carbon cell is

attributed to Georges Leclanche, a Frenchman. This type of battery is avail-

able in a variety of si ...