Modern Toil

Wow…..You could never tell you work in IP!!! Your concise explanation was waaayyyy over my head. I bought a AcuRite 01515 weather station and am thinking of getting one of the bridges. Can I plug in the power, connect to my router, and start getting info from the station over a pc computer AND an iphone/ipad? The reason I ask, and pardon my ignorant questions, is because I have a Foscam camera that we set up to monitor when away from home on an iphone,and I’m always having to keep changing the IP addy on my computer to be able to access it. Will I run into the same problem with this, or is it truly “plug n’ play” ?

I am having trouble getting the bridge to work.
The lights are both steady. Blinks once maybe every 2 minutes. My Actiontec router GT724WG shows the Mac address as 24:C8:6E:00:00:00 instead of 24:C8:6E:01:0B:54. I can view the web page of the bridge. So far tech support at Acu-Rite has not been that helpful. Any help would be greatly appreciated.

Thanks for the great info. I have run with your idea and am currently developing a php solution with a database driven front end. I have two questions.

1. Have you decoded the data values from the bridge. It appears to send 13 different bridge values.

2. Have you experienced the bridge sending data to your rerouted DNS entry for about 5 minutes and then reverting to sending to the my backyard weather link? I am wondering if they have a hardcoded IP address or Secondary DNS server.

Thanks! If you are interested in the code I would be happy to share.

Hi Rich,
Thanks for the reply. I think I have gotten close with the Barometric Pressure. It is not exactly what their site shows as I think they are making a correction based on region. I emailed the company to see if they would give me the spec for the variables. Long shot but worth a try.

I also figured out my intermittent problem. It was just a DNS issue.

Can you send me your email address so I can send you a link to my server to check out the working copy.

Hi!

Do you know if the bridge posts data for all sensors in range, or just the 3 sensors that you can have configured on your aculink account at any one time?

Cheers,
B

My router has a whole bunch of settings. They have names including:
policy routing
static route
RIP
DNS proxy
Static ARP
IP filtering
One-to-One NAT

But I get the feeling they won’t do the trick…

From fiddling about with my various sensors, and due to glitches in the aculink dashboard that sometimes end up showing me data from four sensors, I get the feeling the bridge must report all sensors but aculink might only actively store the data for three…

Timothy C was looking for some info about how certain values are calculated.

This spec sheet might be helpful.

http://www.weatherequipment.com/assets/images/PDF/Five-in-One-Professional-Weather-Station-Specifications.pdf

Bob-

I haven’t been able to decode the pressure data yet, but I’m interested in the code you’ve got so far for interpreting the data.

I’ve finished up my Raspberry Pi tonight and it’s putting out great data stripped from the network directly without any trickery. (No DNS, no DHCP, no Web server, no proxy) I just now need to figure out how to interpret everything.

Here’s a sample of what the Pi currently spits out:

id=24C86E017A74&mt=pressure&C1=495B&C2=0DCC&C3=011F&C4=0273&C5=85F8&C6=17C0&C7=09C4&A=08&B=22&C=06&D=07&PR=982E&TR=84E0{
id=24C86E017A74&sensor=09093&mt=tower&humidity=A0570&temperature=A018300000&battery=normal&rssi=2
id=24C86E017A74&sensor=00770&mt=5N1×38&windspeed=A003730000&humidity=A0610&temperature=A017888888&battery=normal&rssi=1
id=24C86E017A74&sensor=09093&mt=tower&humidity=A0570&temperature=A018300000&battery=normal&rssi=2
id=24C86E017A74&sensor=00770&mt=5N1×31&windspeed=A003270000&winddir=C&rainfall=A0000000&battery=normal&rssi=1
id=24C86E017A74&sensor=09093&mt=tower&humidity=A0570&temperature=A018300000&battery=normal&rssi=2

I’ve got the pressure working. At least absolute pressure that agrees with MBW.

I used this data sheet for the formulas:
http://www.hoperf.com/upload/sensor/HP03S.pdf

I just made an educated guess picking it based on the specs. I’m not sure it’s actually the right data sheet. However, the formulas seem to work.

What’’s goofy is that they list D1 and D2. These seem to be the values PR and TR coming from the bridge.

Here’s my code for parsing the data. It’s a mess, but it works. I’m sure there’s probably a better way to do this. Maybe later I’ll clean it up and put in some more comments.

#!/usr/bin/perl

$celsius = ‘*’;
$farenheit = ‘*’;
$humidity = ‘*’;
$windspeed = ‘*’;
$winddir = ‘*’;
$rainfall = ‘*’;
$raintotal = ‘0′;
$pressure = ‘*’;
$pressure_in = ‘*’;

while ($line = )

{

$index = index ($line, ‘mt=pressure’);
if ($index != -1)
{
$c1 = substr $line, index ($line, ‘C1=’) + 3, 4;
$c2 = substr $line, index ($line, ‘C2=’) + 3, 4;
$c3 = substr $line, index ($line, ‘C3=’) + 3, 4;
$c4 = substr $line, index ($line, ‘C4=’) + 3, 4;
$c5 = substr $line, index ($line, ‘C5=’) + 3, 4;
$c6 = substr $line, index ($line, ‘C6=’) + 3, 4;
$c7 = substr $line, index ($line, ‘C7=’) + 3, 4;
$a = substr $line, index ($line, ‘A=’) + 2, 2;
$b = substr $line, index ($line, ‘B=’) + 2, 2;
$c = substr $line, index ($line, ‘C=’) + 2, 2;
$d = substr $line, index ($line, ‘D=’) + 2, 2;
$pr = substr $line, index ($line, ‘PR=’) + 3, 4;
$tr = substr $line, index ($line, ‘TR=’) + 3, 4;

$c1 = hex ($c1);
$c2 = hex ($c2);
$c3 = hex ($c3);
$c4 = hex ($c4);
$c5 = hex ($c5);
$c6 = hex ($c6);
$c7 = hex ($c7);
$a = hex ($a);
$b = hex ($b);
$c = hex ($c);
$d = hex ($d);
$pr = hex ($pr);
$tr = hex ($tr);

$d1 = $pr;
$d2 = $tr;

if ($d2 >= $c5)
{
$dut = $d2-$c5-(($d2-$c5)/2**7) * (($d2-$c5)/2**7)*$a/2**$c;
}
else
{
$dut = $d2-$c5-(($d2-$c5)/2**7) * (($d2-$c5)/2**7)*$b/2**$c;
};

$off = ($c2 + ($c4 – 1024) * $dut / 2**14) * 4;
$sens = $c1 + $c3 * $dut / 2**10;
$x = $sens * ($d1 – 7168) / 2**14 – $off;
$p = $x * 10 / 2**5 + $c7;

$t = 250 + $dut*$c6/2**16-$dut/2**$d;

$pressure = sprintf (“%.0f”, $p / 10);
$pressure_in = sprintf (“%.2f”, $p / 338.6 );
};

#
# Wind direction is reported as a single hex digit
#

$index = index ($line, ‘winddir’);
if ($index != -1)
{
$winddir_frag = substr $line, $index + 8, 1;
$winddir = hex ($winddir_frag) * 22.5 ;
};

$index = index ($line, ‘rainfall’);
if ($index != -1)
{
$rainfall_frag = substr $line, $index + 10, 6;
$rainfall = $rainfall_frag * 0.0001;
$raintotal = $raintotal + $rainfall;
};

#
# Wind speed is reported as centimeters per second
# Convert to miles per hour by dividing by 44.7
# Rounded to nearest MPH
#

$index = index ($line, ‘windspeed’);
if ($index != -1)
{
$wind_frag = substr $line, $index + 11, 5;
$windspeed = sprintf (“%.0f”, $wind_frag / 44.7);
};

if (index ($line, ‘temperature’) != -1)
{
$temp_frag = substr $line, index ($line, ‘temperature’) + 13, 4;
$celsius = $temp_frag / 10;
$farenheit = $celsius * 9/5 + 32;
};

if (index ($line, ‘humidity’) != -1)
{
$humid_frag = substr $line, index ($line, ‘humidity’) + 11, 3;
$humidity = $humid_frag / 10;
};

print “33[2J”; #clear the screen
print “33[0;0H”; #jump to 0,0

use POSIX qw(strftime);
print strftime(“%a, %d %b %Y %H:%M:%S %z”, localtime(time())) . “\n”;

print “\n $line \n”;
print “temperature F = $farenheit\n”;
print “humidity % = $humidity\n”;
print “wind speed MPH = $windspeed\n”;
print “wind direction degrees = $winddir\n”;
print “rain in last 36 seconds in inches = $rainfall\n”;
print “total rain since last restart in inches = $raintotal\n”;
print “absolute pressure in mmHg = $pressure\n”;
print “absolute pressure in inHg = $pressure_in\n”;
};

Just had a significant rain event. It’s clear my interpretation of the rain data isn’t correct.

I thought it was the amount received during a 36 second period, but it’s obviously is based over a longer time period.

I’ve been logging the data from the sensors, so hopefully it will become clear.

My understanding is that the “corrected pressure” is the value “reduced to sea level”, which is the norm for weather station reporting. It takes station altitude out of the picture and allows isobar maps to make sense…. or so I’ve been told.

AcuRite’s version of corrected pressure uses a patented method with a “learning period” that eliminates the need for a user to enter the station altitude into the device. The formula is outlined in the first data sheet I posted.

The normal way to get the corrected pressure is to take your station’s altitude into account, but I haven’t looked up the formula for that. Apparently there are different formulas for weather and aviation.

As for AcuRite’s method, I’ll probably just ignore it. It just seems easier to take station altitude into account than calculating running averages over time for this application.

Yeah. That’s what I’m seeing for rain…multiples of 254.

That surprises me as I was expecting it just to be the number of bucket tips.

Have you considered a third-party package for reporting and graphing? I’m looking into the possibility of using weewx, but I’m not sure I fully grasp how to pass the data to the program.

The author says I can either populate their database and execute their report engine, or write a “driver” to interpret the data stream. Apparently it sounds like a simple to task to him, but he’s using Phython lingo of which I know next to nothing.

I also now have the bridge reporting to Wunderground at about 1 minute intervals. I have one more change I want to make. Right now I wait until I have all the data I need from the bridge before sending it, but I want to synchronize it with the pressure since that comes from the bridge at 1 minute intervals. KCAELDOR15 is my experimental station.

One of the big advantages I’m getting with this set up is that I get more correct humidity values. My 4n1 sensor is broken and reports 98% humidity constantly. I have a tower sensor mounted under the 5n1 and can use the humidity value from that.

Since I’m hijacking the http://www.acu-link.com name with my name server and I also use comcast name servers the bridge does occasionally get the real address and bypasses my hijacking. I’ll need to work on that.

Next I want to dump the data into a database. I have a local mysql server running so i’ll just add a table to that for weather data. the only charting/graphing I’ve done has been web based and I’ve been using phpgraphlib for that. Right now I just want the weather data as input in my home automation system so charts/graphs aren’t a priority.

Hate to necro an old thread, but how exactly did you get your original script to execute? I have Apache on a Linux box running mythtv already and so far I’ve used mod rewrite to change a url with “messages” in it to execute a “messages.sh” script. However, if passed a URL that has the trailing slash (“messages/”), I get a 404 error where messages.sh/ not found. It would _seem_ to be as simple as adding the trailing slash into the rewrite command, but it doesn’t appear to fix the issue. It’s like Apache treats URLs with trailing slashes as directory requests no matter what.

FYI- I’ve been getting comments about wind direction being wrong from people using the code I posted above.

The problem is that I assumed “North” was digit “0″. That’s incorrect. North is actually “5″, so all the directions are off.

The current corrected code can be found here: http://nincehelser.com/ipwx

Hmmm, parts of the top of code block didn’t copy. It should be when temp 3 MPH

I have the Acurite 5 in 1 and cannot find the MAC address on the console. Wa it on a sticker that fell off or can I find it somewhere else?

Great write-up. Thanks sharing. I am building system similar to Bob’s(Pi based embedded server collecting data)

Just put up a 5-in-1 (outside) and a tower on the inside of the cottage. I’m now tracking both the inside and outside temps from home (gotta love it). Next summer I’m going to immerse the tower in a waterproof container and drop it into the lake. So I can track the lake temp.. Before next winter I want to get a 3M-50 so I can turn up the temp before we head up.
I have a question on the amount of data going back and forth between the bridge and acu-link.. Anyone have any info? Also right now it looks like the bridge is sending data every 12 minutes.. anyone know if that is configurable

Has anyone managed to get the data direct via USB from an Acurite system and not via the bridge?

A few have decoded that there are two main USB messages, (2) type1 (smaller ~8 bytes) and a larger type 2 ~25 bytes.

Since I can take the USB direct to my Pi and decode the two smaller ones, I’m trying to get the deeper data they have on the larger message (which also has their pressure calculations in Pascal no less).