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I paid too much for my adapter did buy it in OZ however try hobbyboards.com
I got my 1wire counter from them and delivery was good. I think the usb adapter is only US$25.00. I paid AUD80 locally can't remember where I got my adapter from (not thermodata.)
CPL (Computer parts land) in ~clayton used to sell the NSLU2 for 135.00. I used an old 20gb laptop drive in a USB housing for my HD. I've got two NSLU2 one as a network storage device and the other as my Aquarium server.
just checked themodata, at that price it seems OK
I got my mine from them. They were also the cheapest I could find.Quote:
Originally Posted by DIYjunkie
I got my USB adapter today after ordering it yesterday. $45 including express delivery from thermodata if anyone is after one.
On the down side no-one locally has an NSLU2 in stock until the end of the week :roll: I might load linux & owfs on an old pc I have lying around so I can start playing.
When you get NSLU2 unslung and owfs loaded the easiest way to test 1wire is just call up the web interface. you just type the NSLU2 IP followed by ":3002" this will provide access toe owfs dynamic web pages. All the 1wire devices it finds on the network will be displayed. You can see each device and clicking on the device shows all device parameters. It even shows data errors on the communication lines.
I will outline best method for data gathering latter...gotta fly
cheers rob
Well, after much reading, frustration :banghead , more reading :ug , a couple of smacks in the forehead :stupid followed by more reading :coffee I've managed to get my brand new NSLU2 "unslung", owfs loaded and showing the temperature on my temporarily breadboarded temp sensor... :thumbQuote:
Originally Posted by Bad Inferno
Before I go running a lan cable under the house to my tank I'd like to get it a bit further, I guess I need to get rrdtool on there, somehow setup a basic web page, and then try recording data.. care to give me some clues? (Thanks!)
OK sounds like you progressed well....I'll PM you the details of how to collect data however their is a couple of things you will need to do
1. use ipkg install for a couple of other things
#ipkg install bash
Will let you run a bash shell script
#ipkg install gawk
Will let you do calculations on your 1wire data within a script
# ipkg install rrdtool
Will let you setup trend files. (I'll send you a setup file to get you started, once installed)
2. Setup a simple home network follow these instructions
http://www.nslu2-linux.org/wiki/HowTo/SimpleHomeWebsite
3. pm your email address to me and I'll send 3 files and some instructions..
1. rrdtool setup file to create a trend database
2. a simple script to populate the trend file say once every 2 minutes
3. a script to create a trend file from the rrd database.
Each of these files are just some simple english commands. However you will need bash installed and the simple web server so that you can view your trend.
rob
OH you may need a couple of text edit commands for the vi editor
#vi scrap (opens a new file called scrap)
i (which is lower case "i" goes into insert mode to add text)
[esc] (enables you to type global type commands see below)
dd (deletes a line, "5dd" deletes 5 lines)
yy (yanks line, copies current line)
p (inserts yanked lines back, ie paste)
:wq (saves (ie writes) and quits)
:quit! (quits without saving)
once you save & quit, to view the file from the command line
#cat filename (cat shows contents of ascii files, you may need to add a "./" infront of your files for some commands ie #cat ./filename)
This is temp sensor I used for monitoring my reservoir temperature. Just used a piece of 1/4" tube and a cable gland. Squirted silicone up the tube to seal the connections and had an old cable relief from a power plug to neaten the end. I drilled a hole in the bottom of my barrel. Why monitor this temp i hear you ask...well I am trying to get a relationship between qty water changed and the drop in Aquarium temperature. ie with water temp at 18" and changing 40 litres aquarium will drop x degrees. This temperature will be used in the water change algorithm to automatically change x litres at a time based upon current reservoir temp and not drop the aquarium too much. I do not heat reservoir and as such may elect to change 2 x 20 litres over the day instead of 40 litres straight up. Also would not change water if temp is greater than 29 degrees. etc Once you have a system setup each temp device is only ~5.00 each so you can go crazy in what temp you monitor. I was thinking of putting 5 sensors along a tube say 40 cm long and try and get a temperature profile both vertical and horizontal in various parts of the tank and test out different positions for heaters and canister returns etc to optimise temperature throughout the tank.
http://img.photobucket.com/albums/v3...ire_temp-1.jpg
DIY-J Thought I would give a quick note on scripts as I wont be around until Sunday arvo..Make sure you did the other installs bash, gawk etc as shown above including the home website stuff before proceeding. I use "dyndns" to provide a simply and free web address mapped to my slug so I can see my Aquarium data over the internet , anyhow here are the scripts to get you going
Introduction
The intent of the following information is to setup continuous trending of one temperature point as an example of data logging using the Linksys NSLU2 and the Dallas 1wire interface. An image file is created every 15 minutes which will contain the last 2 days of data. This image can be integrated into a simply web page so that it can be viewed from a web browser.
http://img.photobucket.com/albums/v3...nway/nslu2.jpg
The NSLU2 device is small, cheap and takes a small amount of power to run and does not require your computer to be running to log the data.
Using these principles you can easily extend this to many more temperatures or really any 1wire device that provides information. e.g. a 1wire counter connected to a flow meter or an Analog input (A/D) which monitors pH or conductivity.
Prerequisites
Your NSLU2 must be using the linux unslung 6.8 firmware
http://www.nslu2-linux.org/wiki/ and be running the simple home website setup http://www.nslu2-linux.org/wiki/HowTo/SimpleHomeWebsite
Packages installed
owfs http://www.owfs.org/index.php?page=nslu2
rrdtool http://oss.oetiker.ch/rrdtool/
bash
gawk
Time & Date
Make sure your time is set correctly...from the command line just type #date -you can use the linksys interface to set the time / date. For date and time linux actually uses the number of seconds since midnight from 1970. Thats how RRD saves the time to its files. Not that hard and you will start to like it after you see the power when manipulating trends durations. If you want to see the linux time use #date +%s -it will print out the seconds. WARNING if your date is incorrect and you happen to write data to the RRD database say 10 hours in advance, you will not collect any more data for 10 hours... My SLUG is probably looses 5-10 seconds a day. I used to sync to a network time server however would not recommend this approach. Its in the to do basket in how best to sync time. You should get within 5-10 seconds a day as standard.
RRDTool database creation
The following needs to be just run from the slugs command line. create a directory rrd in public. Copy the lines from here and then you just need to right click in the telnet window to paste it. make sure the complete line contains all data before pressing return.. This will create a database called aqua_temp.rrd
rrdtool create /public/rrd/aqua_temp.rrd --start 1178926536 --step 300 DS:AT1:GAUGE:600:-10:100 DS:AT2:GAUGE:600:-10:100 RRA:AVERAGE:0.5:1:1440 RRA:AVERAGE:0.5:4:2160 RRA:AVERAGE:0.5:12:8760 RRA:MIN:0.5:288:1825 RRA:MAX:0.5:288:1825
The above actually creates two data points within the RoundRobinDatabase ( AT1 and AT2) The scripts below only use AT1 (to try and keep it simple) however when you hook up another temp sensor you can use the same database and write to AT2 for your second sensor.
Create a SCRIPT to push data into RRDTool (/public/read_script)
#!/bin/bash
OWSERVER="-s 3002"
### Force Simulataneous 1wire conversion ###
/opt/bin/owwrite $OWSERVER simultaneous/temperature 1
### Read 1wire data and convert into engineering units ##
TempAqua =$(/opt/bin/owread $OWSERVER 28.11BF97000000/temperature | /opt/bin/awk '{printf "%3.1f\n",($0)}')
### Push Data into Trend Files ###
rrdtool update /public/rrd/aqua_temp.rrd N:$TempAqua
make sure you #chmod 777 read_script -so you can run it. once created you should be able to run the script
#./read_script
Maybe you could add a line to the end of this script
echo $TempAqua
this will print the temperature out when you run the file…obviously change my 1wire ID 28.11BF97000000 to your 1wires ID number
Create a SCRIPT to make the trend file (/public/graph_script)
Just change the time scale by changing duration (= seconds) the etime and stime is so that the time is in increments of 300 seconds. This is supposed to provide for faster RRDTool database lookup.
#!/bin/bash
etime=$(/bin/date +%s)
step=300
duration=127800
etime=$((${etime}/${step}*${step} ))
stime=$((${etime}-${duration}))
## Aquarium Temperature GRAPH ##
rrdtool graph /website/degc1d.png --start $stime --end $etime \
--upper-limit 32 --lower-limit 27 \
--rigid \
--slope-mode \
--width 422 --height 150 --title "Temperature" \
--vertical-label "Degrees C" \
DEF:degc1=/public/rrd/aqua_temp.rrd:AT1:AVERAGE \
LINE1:degc1#FCB521:"Aquariumm=" \
VDEF:DEGClast=degc1,LAST GPRINT:DEGClast:"%3.1lf%s" \
VDEF:DEGCavg=degc1,AVERAGE GPRINT:DEGCavg:"avg=%3.1lf%s" \
--watermark "Aquarium Temperature Graph"
This will create your graph named degc1d.png….The first time you run this script it will create degc1d.png. go into /website and issue the following command which will make it readable.
#cd /website
# ls -all degc1d.png -This just shows the file privileges
#chmod 666 degc1d.png
# ls -all degc1d.png -This should now show rw-rw-rw-rw
You should be able to view this file from your PC, just navigate to the slugs website directory and open it. if your running the "home" webserver you should be able to go to internet explorer and type your "slugIP's/degc1d.png" and it will display the graph.
Get the scripts to run automatically
OK your done, at this point you should be able to generate your trend files manually by typing ./graph_script -only thing left is to schedule these scripts to be run so that when you call up the trend file it contains the latest data. Modify /etc/crontab to start the two scripts. We will read the data every 2 minutes and recreate your graph every 15 minutes.
SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=""
HOME=/
# ---------- ---------- Default is Empty ---------- ---------- #
0 0-23/8 * * * root /usr/sbin/CheckDiskFull &>/dev/null
0 0 * * * root /usr/sbin/WatchDog &>/dev/null
*/2 * * * * root /public/read_script &>/dev/null
*/15 * * * * root /public/graph_script &>/dev/null
If you added "echo $TempAqua" to your read_script maybe comment it out (ie #echo $TempAqua) as you are now running the script automatically in the background.
Thats it you should now have a temperature graph being generated every 15 minutes. If you've setup your web server you will be able to see this from work ! You can easily add an email alert if temp is high or low however I'll cover that later. For now put on a couple more temperature devices and start measuring your house inside and outside temperatures as well.
[i]Why use the awk command in the read script ?[/i]
awk is used for both formatting and providing calculations. All you need to do is pipe data into awk and manipulate the data. If the data is a file that contains two items the first item is identified with $0 and the next with $1. The following example brings my PH value which is a 1-5VDC coming from a 1wire A/D chip. Its a bit tricky however volt.A become $0 in the calculation. The pipe symbol "|" is used to transfer the value of Volt.A to the awk command
PH=$(/opt/bin/owread $OWSERVER 20.B71F05000000/volt.A | /opt/bin/awk '{printf "%4.2f\n",((($0-1)/1.6)+5.5)}')
OK we've got the pH now lets calculate the CO2 concentration...well for this calc you need two parameters pH and KH...$PH comes from the command above and kh comes from a text file. In this case the text file at the end of the awk command is where it will get its data from ie $0 = kh value. I check my kh value once per week and update the value in the text file if required. Here is the calculation, this time $0 represents the value in my kh_value text file. You need to declare PH=$PH so that awk is happy within its formula. The CO2 calc is (3 times kh) times (10 to-the-power-of (7 minus pH)
CO2=$(/opt/bin/awk -v PH="$PH" '{printf "%3.1f\n",((3*$0)*(10^(7-PH)))}' /public/kh_value.txt)
Another example..I monitor the amount of flow that is drained from my aquarium with a $60.00 flow meter. It gives out 4100 pulses per litre and I have a 1wire counter measuring the pulses. The counter never looses the count even when power is off. Thus Accum_Flow is now measuring directly in litres with the benifit of doing it all oon one line of code within the script file.
Accum_flow=$(/opt/bin/owread $OWSERVER 1D.EBEF0900000034/counters.A | /opt/bin/awk '{printf "%g\n",($0/4100)}')
Gee's hope I didn't miss anything out
:roll:[img][/img][img][/img]