[K12OSN] Outdoor Thin Client (and possibly wireless)

ssanders at coin.org ssanders at coin.org
Thu May 18 03:16:03 UTC 2006

I'll go along with Dale on this one. I am a music guy, and something
like this is what I have dreamed of for years. I have not used Myth, but
I think it would be overkill as well.

Basically, I use Madman http://madman.sourceforge.net/ to stream music
to the thin clients. I appear to have to use ESD/Gnome instead of ALSA,
but this is my main need for audio so that is not a problem. Any thin
client in any room (and the garage) can listen to it's own playlist from
the common pool of music. A great thing about Madman, is that it is just
a 'music manager'. It depends on correct tags, and feeds choices to XMMS
in a live playlist. If I want to hear Reggae from 1974 and older, it's
just a few clicks away. If I want to hear every song with the word
'angel' in the Artist/Title/Album/Year/Genre/Comments fields it's just a
few clicks away. 

This is all well and good for indoors, but I wanted outdoor choices as
well. Madman won't sync multiple clients but can send as many audio
streams as you have local bandwidth for. What I did was research
low-power (legal) FM transmitters to play through some/many FM radios.
Tune every FM radio in the house to the same station, and that gives you
the luxury of independent volume levels.  The legal limit is I think
100mw (that's only 1/10 of a watt). There are a plethora of *very* low
power FM transmitters around, because of the glut of iPods and many
portable MP3/CD players. These are mostly intended for vehicle use,
where the transmit range is from the car seat two or three feet to the
FM antenna of the car radio. These are all over Ebay and your local
*Mart on bubble cards for USD $3 on up. A hundredth of a watt won't work
for outdoor/home entertainment.

After searching a lot, I decided on a C. Crane FM transmitter. It has an
external whip antenna, runs the full legal limit of transmit power and
has a completely tunable frequency range. Many (most?) of the tiny,
antenna-free cheapies have three preset transmit frequencies. You find
the one that is least interference-free and use it. It also has .5
increments, so it can tune more precisely than most digital FM
receivers. If you search online for XMFan you can find discussion of a
potentiometer inside that can be turned up. This is for testing only of
the wider Frequency range, of course... 

The C. Crane is pricey at abt USD $70 retail. For about USD $500 you can
get a Ramsey kit that will transmit two watts, and pretty much break
every FCC Part 15 law there is. I found mine on Ebay for USD $25, rarely
used. The tiny antenna-free transmitters often only operate on AA or AAA
batts, the C. Crane has a 12vdv jack as well.

So, my outdoor music arrangement consists of putting the C. Crane
Transmitter on whatever thin client with a soundcard that is physically
closest to the outdoor area. Tune every radio in the house, every car in
the driveway, every jambox you can put in the yard to the same freq, and
enjoy what you want to hear, at varying volume levels.

This is all well and good, but does not address the wifi remote control
you mentioned? A nice feature of Madman is that is can optionally run a
local web server, and anyoneo on your LAN can connect to it with a
browser and search/play/manipulate the playlist. I don't understand the
need for a *.G wifi card, unless that's all you have. You can get 200mw
*.b wifi cards for USD $9 if you shop around. You don't need the extra
bandwidth at all for this use.

Boot to a Knoppix disk in a laptop for the deck/garden/patio, and learn
how to get wifi working on it with whatever card you are using. Connect
to the Madman web server, and you can control the playlist from anywhere
within your wifi range (which easily will be greater than the FM
broadcast range).

There are lots of outdoor speaker choices, if you want something
semi-permanent. Build your outdoor enclosure, put a garage-sale FM
receiver inside it, and go to Worst Buy or Ebay and get some outdoor

Or you could boot the laptop with 'knoppix 2', get your wifi card
working, then at the shell prompt: 'X -query server'. This will give you
a regular K12LTSP client login over wifi.

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