Idea

Keep a logfile with the most recent single line
Use the munin plugin to generate munin-compatible data from the log file

Setup

Checkout the munin plugin code:

$ cd /usr/local/src
$ git clone git://git.cweiske.de/usb-wde1-tools.git
$ cd usb-wde1-tools

A process needs to watch the USB interface and log the last line with temperature data into a log file. You can do that manually with
```
$ socat /dev/ttyUSB0,b9600 STDOUT |./munin/log-single-line.sh test.log
```
The most easy way is to run
```
$ cd munin && nohup ./usb-wde1-log-last.sh &
```
once. It backgrounds the logging process and logs into /tmp/usb-wde1-last. This process needs to be started whenever the machine is rebooted.

You can run make to install the init script.

Link the munin plugin:

$ cd /etc/munin/plugins
$ ln -s /usr/local/src/usb-wde1-tools/munin/usb-wde1_ usb-wde1_temperature
$ ln -s /usr/local/src/usb-wde1-tools/munin/usb-wde1_ usb-wde1_humidity

Configure the plugins Edit /etc/munin/plugin-conf.d/munin-node and add the following lines:

[usb-wde1_*]
env.logfile /tmp/usb-wde1-last
env.host_name House
env.sensors 0 1 7
env.sensor0 Living room
env.sensor1 Kitchen
env.sensor7 Outside

Try it:
```
$ munin-run usb-wde1_temperature autoconf
```
should echo "yes"
```
$ munin-run usb-wde1_temperature config
```
should display the plugin configuration with all environment variables set
```
$ munin-run usb-wde1_temperature
$ munin-run usb-wde1_humidity
```
should display the current values from the log file
You are done - enjoy.

Debugging & Development

The dummy data generator is a small php script that generates log lines as they would come from the usb-wde1 usb port:

$ ./dummy-data-generator.php |./munin/log-single-line.sh test.log

Local (non-installed) plugin setup:

$ cd munin
$ ln -s usb-wde1_ usb-wde1_temperature
$ ln -s usb-wde1_ usb-wde1_humidity
$ cd ..

Running the munin plugin for development purposes is also relatively easy since you can pass the environment configuration variables from the munin configuration on the command line:

$ logfile=test.log sensors="0 1 7" ./munin/usb-wde1_temperature

When you have problems running the munin plugin, try to remove the line

env.host_name House

from file usb-wde1_

Permission errors

cu: open (/dev/ttyUSB0): Permission denied
cu: /dev/ttyUSB0: Line in use

Only way that I found to fix this was change ownership of /dev/ttyUSB0 to uucp:

$ chown uucp /dev/ttyUSB0

HTML/Plain text output

You may use htmlreport/gen-html.php to generate HTML or plain text files with the temperature and humidity information.

Install PHP and the PHP rrd extension (pear install pecl/rrd) to make it work.

Run gen-html.php every 5 minutes.