Home Hacking Projects for Geeks

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Chapter 9, Create Time-Shifted FM Radio

Whole-House Audio

In this phase, you’ll create a system for distributing audio from your com-

puter throughout your house. If you’re lucky enough to already have such

a system in place, or if you only plan to listen to the time-shifted radio

through a single pair of speakers, you can skip this phase.

Sound quality, cost, ease of installation, and portability are the most sig-

nificant factors when choosing a whole-house audio system. At the high

end, you can install whole-house audio that provides home theater–quality

sound to multiple speakers in every room of your house. These systems

typically provide controls built into the wall of each room that allow you

to control the volume and other aspects of the audio equipment. You can

find an excellent description of such systems at http://www.hometech.com/

learn/audio.html.

Quality is not the most important factor to me, though. Cost is important,

because honestly now, there are much more important things to spend

money on than whole-house audio. Plus, I dread the idea of running wires

all around my 1950s house, and it would take me so long that I’d probably

never complete the project anyway. Portability is important, too. If I move,

I wouldn’t want to leave a wired whole-house system behind. Chances are

good that it wouldn’t improve the value of my house much, so I’d be taking

a loss.

For this project, I found a whole-house audio solution with acceptable qual-

ity that was less than $100, installed in about an hour, and that I can easily

take with me anywhere I move. This system uses a wireless protocol, similar

to 802.11x, but significantly easier to install (although less secure). And as

if that weren’t perfect enough, it turns out that I already had compatible

wireless clients spread around my house. Basically, I’m going to install a

pirate radio station.

You don’t need to be a rebellious DJ-with-a-cause to

set up your own pirate radio station. In fact, you don’t

even need to be a pirate, or to break any laws. You can

legally set up an FM radio transmitter that can broad-

cast a short distance, as illustrated in Figure 9-7. I’ve

done this in the past to connect my MP3 player to my

car stereo. For about $30, I bought a radio transmitter

from the neighborhood electronics store. That transmit-

ter worked only for a few feet, though, so it’s not good

enough to broadcast around an entire home.

This project will provide some background information

about FM transmitters and the laws that regulate broad-

casting in public frequencies. I’ll walk you through the

process of choosing from the many FM transmitters

Figure 9-7. Want your MP3s in a different

room? Build a tiny radio station!

Whole-House Audio

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11/24/2004 1:55:49 PM