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Moved RPi specific information to the Wiki

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Tom Keffer
2015-01-30 00:28:21 +00:00
parent eba963371a
commit 9573689216
2 changed files with 9 additions and 69 deletions
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TODO.txt
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@@ -1,5 +1,3 @@
Links to Wunderfixer seem to have gotten lost on the website.
wee_config_device --dump should be able to dump to a metric units database.
See if it is possible to make cheetahgenerator not require a default wx_binding

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docs/usersguide.htm
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@@ -3487,74 +3487,16 @@ Nov 27 20:30:21 rpi weewx[5607]: **** Generator terminated...
Nov 27 20:30:23 rpi weewx[5607]: genimages: Generated 11 images in 2.53 seconds</pre>
<p>See the section on option <span class="code">
<a href="#record_generation">record_generation</a></span>.</p>
<h3>Raspberry Pi</h3>
<p>Running <span class="code">weewx</span> on a Raspberry Pi has become
very popular. You'll have to look elsewhere for instructions on setting up
your RPi, but there are a few very common problems with
setting them up.</p>
<h4>NTP</h4>
<p class="warning">You must run NTP on your RPi, and you must make sure it
starts and updates the time <em>before</em> <span class="code">weewx</span>
runs.</p>
<p>The reason is that the RPi does not have an onboard clock. If you lose
power and, say, an hour later it comes back, your RPi will simply pick up
where it left off — one hour behind. The symptom that something is amiss
is that everything will appear to be running normally, but your webpage
will not get updated (at least, until the length of the power failure has
elapsed).
<a href="https://groups.google.com/forum/#!searchin/weewx-user/clock/weewx-user/tmbrOC6-UiM/1xohs9WUAW8J">
Here's one user's nice analysis of the problem.</a></p>
<p>What this means is that it is not enough to simply run the
<span class="code">weewx</span>
daemon. You need some way of delaying its start until NTP is not only up
and running, but has contacted a time server and corrected the RPi's
clock. </p>
<p>Several users are working on a solution to this problem. Perhaps you'll
be the one to figure it out?!</p>
<h4>Use a high-quality SD card</h4>
<p>The SD card supplied with most RPis seems to be of very low quality. Make sure
you use a good, Class 10 card. User William Phelps reports, "You can usually spot
a failing card by watching the kernel I/O wait time. Once the card starts to go, the
I/O wait time will increase significantly."</p>
<h4>FTP</h4>
<p>Many Raspbian versions of Debian do not seem to include an FTP client. You may have
to install this if you plan on using FTP.</p>
<pre class="tty">
sudo apt-get install ftp
</pre>
<h4>Use a good power supply</h4>
<p>A lot of problems with the RPi seem to center around
inadequate power supplies. Many weather stations can
demand a lot of current through their USB connection.
Make sure your RPi can supply it, either by getting a good
power supply (I use
a <a href="http://www.amazon.com/gp/product/B00J3IB7A2/">Innogear
1.5 A supply</a>, which costs all of $5.50 from
Amazon), or, alternatively, by using a powered USB hub.</p>
<h4>Run a lightweight web server</h4>
<p>The RPi is astonishingly powerful for its size, but it does have its limitations.
If you plan on running a webserver on it, perhaps to serve your home, then use a
lightweight one, such as <a href="http://www.lighttpd.net/">lighttpd</a>
or <a href="http://nginx.org/">nginx</a>. Apache works, but it uses far more
memory. In my tests:</p>
<table style="width: 30%" class='indent'>
<caption>Memory requirements of 3 common webservers on a Raspberry Pi</caption>
<tr class="first_row">
<td>Webserver</td><td>VIRT</td><td>RES</td>
</tr>
<tr>
<td class="first_col">Apache</td><td>222 Mb</td><td>3 Mb</td>
</tr>
<tr>
<td class="first_col">lighttpd</td><td>7 Mb</td><td>2 Mb</td>
</tr>
<tr>
<td class="first_col">nginx</td><td>11 Mb</td><td>1.7 Mb</td>
</tr>
</table>
<h3>Fine Offset USB lockups</h3>
<h3>Raspberry Pi</h3>
<p>
See the <a href="https://sourceforge.net/p/weewx/wiki/"><span
class="code">weewx</span> wiki</a> for up-to-date information on <a
href="https://sourceforge.net/p/weewx/wiki/Raspberry%20Pi/"><i>Running
weewx on a Raspberry Pi</i></a>.
</p>
<h3>Fine Offset USB lockups</h3>
<p>The Fine Offset series
weather stations and their derivatives are a fine value and
can be made to work reasonably reliably, but they have one