Tomasz Korwel
programmer, administrator, engineer – my everyday fights with reality

A comment posted under one of my older posts reminded me that it can be a good idea to resurrect and finish my HVAC zoning project I shelved some time ago. Main cause I did so was that I couldn’t get dz compiled. I didn’t have time to mess with it any longer then, but I decided to give it a try this time. It turned out that over last two years Ubuntu project went forward so much that this time dz compiled successfully the very first time I tried. So right now I have a spider web construction on my desk consisting of two 1-wire temp sensors and two servos run by phidget boards. And they work. Servos are opening and closing according to changes in the temperature of my office. They have no influence as they aren’t running registers yet, but they proved to work. Now it’s time to run wires around the house and motorize registers.

Stay tuned.

We finally moved in to our new house. After couple of days spent on cleaning, unpacking and making ourselves comfortable we figured out one thing – the HVAC system is just a disaster.

First – the thermostat is in the worst place in the house. Simply first test shows that while the thermostats shows 1 degree differences, the actual temperature it that room floats more than 2 degrees in each direction.

Second – all registers are broken – none of them shuts completely and none of them works smooth

Third – the A/C unit and fan are probably undersized (I still have to make measurements) – it needs to work for more than 1h to cool down the room by 1 degree.

A lot of work is waiting but it only makes me more motivated to quickly finish that project.

Technorati Tags: HVAC, thermostat, temperature, registers, A/C

Here is small help and instruction howto install OWFS on new, out of the box Ubuntu 6.06 server edition.

1. Dependencies

First off all we need to take care of some needed packets:

comp# apt-get install \
       automake \
       autoconf \
       autotools-dev \
       gcc \
       g++ \
       libtool \
       libusb-dev \
       fuse-utils \
       libfuse-dev \
       swig \
       python2.4-dev \
       tcl8.4-dev \
       php5-dev

Agree for all additional needed packages apt will want to install

2. OWFS

Thanks to having fuse libraries already instaled we can go directly to the final step. First download the sourse.

comp# cd /usr/src
comp# wget http://umn.dl.sourceforge.net/sourceforge/owfs/owfs-2.4p3.tar.gz

Then extaract the file

comp# tar zxpf owfs-2.4p3.tar.gz

Compile and install

comp# cd owfs-2.4p3
comp# ./configure
comp# make && make install

3. Mounting one wire file system

First make sure that fuse kernel module is loaded

comp# modprobe fuse

It good to put it in /etc/modules file to have it automatically loaded during every system startup.

Then create the directory where 1-Wire filesystem will be mounted.

comp# mkdir /var/1-Wire/mnt

Finally we can connect our sensors to that point. In this case 1-Wire hardware is connected to the COM1 (ttyS0).

comp# /opt/owfs/bin/owfs /dev/ttyS0 /var/1-Wire/mnt

Now check if there are files and directories representing our sensors structure:

comp# ls /var/1-Wire/mnt
09.CF9EC8010000
10.64502F000800
alarm
bus.0
simultaneous
statistics
structure
system
uncached

Looks like everything is ok. The 10.64502F000800 (and all xx.yyyyyyyyyyyy) directory represents device on our 1-Wire architecture. First two characters define device family (10 – temperature sensor) the 12 characters after dot represents unique device serial number. You can go into that directory and check more properties of that particular sensor:

comp:/var/1-Wire/mnt/10.64502F000800# ls
address
family
power
r_id
temphigh
trimblanket
crc8
id
present
r_locator
templow
trimvalid
die
locator
r_address
temperature
trim
type

For detailed description of all parameters visit OWFS web site. To make sure our system is working – one last check:

comp:/var/1-Wire/mnt/10.64502F000800# cat temperature
75.3125

Looks good. Now it’s time to run some data collection thing to make those thing more usefull.

Technorati Tags: OWFS, 1-Wire, sensors, 1-Wire architecture

I’ve spent almost whole night and half of today’s morning to get it to work on Ubuntu. Detailed report later – now for those who are interested live (refreshed every 15 minutes) temperature readings from our house:

If the time scale looks like they are outdated – probably they are – it may simple means that laptop lost network connection :-). But don’t worry – they will be updated

I have just got my order placed at Embedded Data Systems. I have one masted 1-Wire bus controller (DS9007U) and couple of temperature sensors.

One day, one hard drive and couple hours later…

For test purposes I hooked up two sensors and put them in our current house – one in bedroom, one in living room. Below you may see temperature reading from last night.

As you may see the temperature in bedroom constantly goes down. Strange uh? No if you keep in mind that we left the window open :-)

As you may also noticed, the graphs ends around 2:50a.m. That’s when my hard drive said “I won’t work any more for ya!”. Lycky me, I had backups.