1wire attic cooling

The attic was hot. Mounting a large fan in the vent seemed to help, but it was drawing 5.5A continuously, which is too much for the thermostat/humidistat my roommate bought. He left it on all the time, which is quite a bit of wasted power. I’ve seen 1wire devices online for quite a while and I’ve always wanted to play with them. The easiest way I can afford to connect sensors to computer is with 1wire. I’ve found my excuse.

The overall idea…
The 1wire temperature sensor is connected to computer with a USB interface. The scripts do magic. The X-10 interface is connected with serial interface. The fan is plugged into an appliance module.

I’ve been a fan of the ExtremeTech books, so I picked up a copy of Weather Toys to get me started.

 

The interface I used the DS9490R 1wire USB adapter.
http://www.hobby-boards.com/catalog/product_info.php?cPath=23&products_id=1503

The temperature sensors I used are DS18S20 1-Wire Digital Thermometer.
http://www.hobby-boards.com/catalog/product_info.php?cPath=26&products_id=93

To connect the sensors and interface:
Cat5e
RJ14 plug
Dual Modular Surface Jack 6 Conductor (only using 4 Conductors)

Additional wiring info
http://www.hobby-boards.com/catalog/howto_wiring_diagram.php?referer=howto_adaptors.php

Once you have the hardware connected, test it with the manufacturer’s viewer to make sure everything is communicating. I used my windows XP laptop for this.
http://www.maxim-ic.com/products/ibutton/software/1wire/OneWireViewer.cfm

Once that’s working, I’m going to go back to my linux box.

I’m a fan of linux. The price is right, it has a pretty large, helpful user base. I chose Ubuntu because it’s my favorite distro this week.

Ubuntu server
http://www.ubuntu.com/products/WhatIsUbuntu/serveredition

Once that’s running and updated, I’m going to install owfs.
http://owfs.org/

You can install from source, but I prefer packages
http://ppa.launchpad.net/smurf/ubuntu/pool/main/o/owfs/
libow-perl_2.7p14-1_i386.deb
owfs_2.7p14-1_i386.deb

These packages depend on an older version of perl, so I modified the .deb for the version of perl installed with Jaunty.
http://ubuntuforums.org/showthread.php?t=636724

Once owfs is installed, I launched the owfs server using a USB device on port 3000.

/opt/owfs/bin/owserver -u -p 3000

To see if you’re able to read you’re sensors, use owdir to list connected devices

/opt/owfs/bin/owdir -s 127.0.0.1:3000

Mine works correctly. one of my temperature sensors is /10.F0B9D5010800
Next I list the attributes I can read from the sensor.

/opt/owfs/bin/owdir -s 127.0.0.1:3000 /10.F0B9D5010800

I’m only interested in the temperature right now, so I read the temperature

/opt/owfs/bin/owread -s 127.0.0.1:3000 /10.F0B9D5010800/temperature

I live in the US and prefer to read my temperature in Fahrenheit. Use -F

/opt/owfs/bin/owread -F -s 127.0.0.1:3000 /10.F0B9D5010800/temperature

If everything seems to be working, you might consider making owserver start with the computer.
https://help.ubuntu.com/community/UbuntuBootupHowto

I have some crappy perl I threw together in a hurry to control the fan and web page generation.

The graphing is just a modified version of http://www.it-slav.net/blogs/?p=75
It works so well that the only changes I made were to rename the script to graphtemp.pl, replace the sensors with my own, and put my website on the graph.

To control the fan, I use X10 and heyu
http://heyu.tanj.com/

The interface I used is the CM11a serial X10 interface.
The module I used to control the fan is the AM466.

I assume reader knows how to make symlinks and adjust permissions accordingly.

# Crontab -l ####################################

* * * * * /usr/bin/perl /home/raging/hvac.pl
*/5 * * * * /usr/bin/perl /home/raging/graphtemp.pl > /home/raging/graphtemplog.txt
*/15 * * * * /usr/bin/perl /home/raging/fanmaster.pl  >> /home/raging/fanmasterlog.txt

# cat fanmaster.pl ##############################
#!/usr/bin/perl
# fanmaster.pl
sleep 10;
use OW;
OW::init("-F localhost:3000");

($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst)=localtime(time);

my $attic = OW::get("10.2FA8D5010800/temperature");
$attic =~ s/^s*(.*?)s*$/$1/;

my $outside = OW::get("10.F0B9D5010800/temperature");
$outside =~ s/^s*(.*?)s*$/$1/;

printf "%4d-%02d-%02d %02d:%02dt",$year+1900,$mon+1,$mday,$hour,$min;
if (abs($attic - $outside) < 10){
printf "Less than 10 Degrees - Turning fan OFFt%.1ft%.1ft%.1fn", abs($attic - $outside), $outside, $attic;
system("/usr/local/bin/heyu off b16");
} else {
printf "More than 10 Degrees - Turning fan ON t%.1ft%.1ft%.1fn", abs($attic - $outside), $outside, $attic;
system("/usr/local/bin/heyu on b16");
}

# cat hvac.pl ###################################
#!/usr/bin/perl
# hvac.pl
use OW;
OW::init("-F localhost:3000");
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst)=localtime(time);

my $duct = OW::get("10.4572D5010800/temperature");
$duct =~ s/^s*(.*?)s*$/$1/;

my $shelf = OW::get("10.72B1D5010800/temperature");
$shelf =~ s/^s*(.*?)s*$/$1/;

my $attic = OW::get("10.2FA8D5010800/temperature");
$attic =~ s/^s*(.*?)s*$/$1/;

my $outside = OW::get("10.F0B9D5010800/temperature");
$outside =~ s/^s*(.*?)s*$/$1/;

open (HVAC, ">/var/www/hvac.htm");
print HVAC "<html><head><title>Temperature</title><meta http-equiv="refresh" content="10" /></head><body>n";
print HVAC "<font size="+2">Temperature Monitor</font><br>n";
printf HVAC "Last Updated: " . "%4d-%02d-%02d %02d:%02dn<br>",$year+1900,$mon+1,$mday,$hour,$min;
if ($duct < 57){
print HVAC "AC cycle is probably <b><font color="#0000FF">ON</font></b><br>n";
} else {
print HVAC "AC cycle is probably <b><font color="#FF0000">OFF</font></b><br>n";
}
printf HVAC "<b>Attic - Outside Difference:</b> " . "%.2fn<br>", abs($attic - $outside);
print HVAC "<img src="hvac/temp0-day.png"><img src="hvac/temp0-week.png"><br><b>Current Outside Temp:</b> $outside<br><br>n";
print HVAC "<img src="hvac/temp1-day.png"><img src="hvac/temp1-week.png"><br><b>Current Attic Temp:</b> $attic<br><br>n";
print HVAC "<img src="hvac/temp2-day.png"><img src="hvac/temp2-week.png"><br><b>Current Duct Temp:</b> $duct<br><br>n";
print HVAC "<img src="hvac/temp3-day.png"><img src="hvac/temp3-week.png"><br><b>Current Bedroom Temp:</b> $shelf<br><br>n";
print HVAC '</body></html>';
close (HVAC);
#################################################