Play It Cool: Incorporating Reporting Mechanisms from Physical Devices
Thermal problems have been a major bane of computers since the very first computer was plugged into AC power. Despite server rooms with raised white flooring and high-end Leibert air conditioners, and over-clocked gaming rigs with water-cooling on the chipsets, heat continues to be a problem that computer administrators and technicians can't ignore.
In the first article of this series, Play It Cool: Remote Monitoring of Equipment Room Temps, a solution was presented for connecting a temperature gauge to your computer and then programmatically accessing it with a number of scripts. In this article, you'll explores how to monitor and report on this information. More importantly, you'll learn how to create a script to audibly announce the current temperature.
Note: This series of articles uses Linux as the operating system of choice, with scripts written for the shell (Bash) and in Perl. For the tasks outlined within this series, I found Linux to be ideal. If you are using a different programming platform, or if you are unable to replicate these methods on Linux, then you should still gain value from these articles. Where possible I will point out analogous possibilities in Windows and other operating systems.
At this point, I had a working sensor and script. Using a variety of methods, I could easily keep myself apprised of the current temperature of my office. The following sections discuss some of the possible reporting solutions.
Maintaining a Textual Log
At bare minimum, I wanted to keep a plain old text log of the temperature. The script shown in Listing 1 accomplishes this goal, with log entries similar to the following:
2006-07-26 15:30 73.7
Listing 1: Appending the current temperature reading to a log file
#!/bin/sh logfile="/var/log/officetemp.log" # Get the current date and time date=‘date -I’ time=‘date +%H:%M‘ # Get the temperature temp=’./get_temp.sh’ # Append data to log echo -e "$datet$timet$temp" >>$logfile
With minimal effort, the same data could be stored in a MySQL database, thanks to the capabilities of the MySQL console application. The code snippet in Listing 2 shows the basics for inserting the data in a database by using the console-this snippet would be appended to the script in Listing 1.
Listing 2: Adding the data to a MySQL database
db="officetemp" table="readings" user="tempuser" pass="goat" cat <<QUERY >./query.tmp USE $db; INSERT INTO $db.$table VALUES ($date, $time,$temp); QUERY mysql -u $user -p $pass <./query.tmp rm -rf ./query.tmp
The output from the reading script can easily be piped into a mailer. This allows the current temperature to be sent to any off-site address-including my cell phone. For example, consider the script shown in Listing 3.
Listing 3: Piping the temperature reading to an emailer (mail_temp.sh)
#!/bin/sh # Email address to send to (my Sprint phone) mailaddr="email@example.com" # Get the temperature temp=‘./get_temp.sh‘ # Build the message cat <<MSG >./message.tmp The current office temperature is: $temp MSG # Send message and clean up mail -s "Current Office Temp" $mailaddr <./message.tmp rm -rf ./message.tmp
With a little extra coding only temperature readings over a certain threshold would be emailed. For example, the following if() clause could be used to decide whether a message should or should not be sent:
threshold="77" result=`echo "$temp >= $threshold" | bc‘ if [ "result" = "1" ] ; then # Email temperature else # Do not email temperature fi
Place Temperature Reading on Web Page
The output could also be redirected to a Web page, where I could monitor it from any terminal with an Internet-connected browser. Listing 4 shows a script to accomplish this task.
Listing 4: Placing the temperature reading on a Web page (web_temp.sh)
#!/bin/sh # Get the current date and time date=‘date -I‘ time=`date +%H:%M` # Get the temperature temp=‘./get_temp.sh‘ # Place temp on an HTML page cat <<HTML >./officetemp.tmp <html> <body>
$date $time - $temp</body> </html> HTML mv ./officetemp.tmp /var/www/officetemp.html
This script creates a simple Web page with the data in a format similar to the following example:
2006-07-28 15:25 - 73.4
The Same Old Problem
As these examples have shown, the structure for the temperature reading is very flexible-the data can be sent easily to numerous places. However, therein lies the problem-I still had to be physically located at or have access to the places where the data was sent, and had to actively monitor the temperature. What I needed was a way to monitor the temperature passively. The solution hit me while listening to a grandfather clock.
"The Current Core Temperature Is "
I decided to create an audible temperature notification. That is, at preset intervals the computer would speak the temperature-loud enough to be heard in and around the office, but not loud enough (or often enough) to be an annoyance. Then, just like the grandfather clock chimes, I could be aware of the temperature of my office without actively having to seek it out.
The first thing I needed was a voice. Being a geek and a science fiction fan, I settled on a female computer voice. I asked my wife to record the following sound files, which I converted to standard WAV format:
core.wav "The current core temperature is" degrees.wav "degrees" 60.wav, 70.wav, 80.wav "sixty," "seventy," "eighty" 1.wav, 2.wav, 3.wav, 4.wav, 5.wav, 6.wav, 7.wav, 8.wav, 9.wav "one," "two," "three," "four," "five," "six," "seven," "eight," "nine" point.wav "point"
Note: I could afford to be fairly selective in my recording, as I didn't expect the temperature to fall below 60 degrees or exceed 89.9 degrees.
Now I needed a script to break down the temperature reading into bits that could be mapped to the appropriate sound files, and a command-line WAV player to play the files in sequence.
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