News items for tag weatherstation - Koos van den Hout

I wanted to do some things in the shed with cabling, some things were not ideal after the solar power installation.

One of the things was that I had a temperature sensor to measure the temperature above the roof, but with all things that happened with cables it ended up hanging below the roof. I moved it back up in the ventilation pipe and with the current temperatures it started measuring 4 degrees Celcius higher immediately.

Since the powerfailure that caused problems for the weatherstation computer ritchie and the conclusion that even after the bios upgrade the serial ports kept failing there was no 'inside the shed' temperature.

But this week I needed a better view of the temperature inside the shed as we're using it to keep some meat cool. So I heated up the soldering iron and the heatshrink gun and made a cable with two DS18B20 sensors in it. I decided that if I started on measuring temperatures inside the shed I also wanted the temperature near the roof.

The interesting bit was adding the two sensors to the w1retap configuration. It seems the whole 1820 family of temperature sensors needs to be set up as a 'DS1820' and w1retap will find out how to read it. Resulting configuration:

28F24C5602000054:DS1820:Tempinside:TEMP0:⁰C::
286B545602000031:DS1820:Temproof:TEMP0:⁰C::

and now I have logging of the temperatures:

2017-12-29T16:28:00+0100 Tempinside 2.812500 ⁰C
2017-12-29T16:28:00+0100 Temproof 2.687500 ⁰C

And it helps us to determine when we need to make space in our fridge and move some other things to the shed to keep them somewhat cool.

I finally had some time to upgrade the BIOS on the Alix 1.c box (ritchie). It was a lot easier to do this with the flashrom utility than to do this with DOS boot floppies!

I just made sure again I checked the old bios version, which turned out to be alixbio3, and upgraded to alixbio8 from the PC Engines Alix 1.c page.

Now the machine boots without a screen attached. I also swapped the mainboard battery as it kept forgetting the current time.

Writing a bios file with flashrom is just changing the -r to a -w from the reading the flashrom command.

But this does not help the serial ports: those seem to be dead for good.

Earlier today there was a local powerfailure. I noticed it while being connected remotely to my server at home, it stopped responding and stayed off-line for a while. I checked the website of the electricity distribution network and it showed a local powerfailure.

Initially my reaction was a bit of interest in how low the radio noise levels would be when I could try the radio at home. By the time I got home power was back on so I never found out.

Some systems at home had to be started by hand, but eventually everything was up and running again, with new kernels booted. Everything came up fine including PPPoE to the outside world.

Later in the evening I noticed the old weatherstation in the shed which measures the temperature and humidity inside the shed seemed inoperational. Checking that weatherstation eventually led to a diagnoses that the 12 volt powersupply for that weatherstation had failed. It was only delivering 7.2 volt. To disconnect that weatherstation for diagnosis I completely shut down the shed computer ritchie. After that it did not come up again. Power came up and the harddisk started spinning but nothing happened after that.

So I also took that computer in for diagnosis. Connected to a keyboard and monitor everything came up fine. Disconnected from the monitor nothing came up.

Slowly it dawned on me that this might be related to an issue which I had read on the PC Engines Alix.1d page :

BIOS update

* beta various updates (release MFGPT timers)
* beta fix VGA DDC issue (boot hang)

Which seemed to be the problem which suddenly started acting up for me which it never did before. But the BIOS clock was also reset so I guess the whole setup was erased and I just did not notice because the default settings were good enough to boot anyway and ntpd sets the clock soon after boot. A simple solution would be a BIOS upgrade.

But preparing a CF card to boot freedos seemed a long way to flash the bios so I tried it via the Heavy Duty Boot pxeboot environment which booted FreeDOS nicely on the alix.1c but it rebooted as soon as I started SB.COM. I guess sb.com searches for bios images on C:\ and the FreeDOS floppy image is A:\

In the end I searched for a workaround and found mention in PC hangs up when no monitor attached - Ubuntu bug #243257 of a wire between pins 12 and 7 in the VGA connector. A piece of wire was bent and inserted into the vga connector and now the weatherstation computer ritchie boots up again.

Next plan is to do the BIOS upgrade via flashrom: In searching for information about the Alix 1.c bios upgrade I'd like to do I came across mention of flashrom.

Today is very windy in the Netherlands, with storm with wind gusts of up to 65 km/h and average windspeed of 36 km/h. But the readings shown by the weather station readings shared in the neighbourhood show quite different values:

2017-02-23 21:49:14 :   HIDEKI Wind sensor
        Rolling Code:    15
        Channel:         4
        Battery:         OK
        Temperature:     4.9 C
        Wind Strength:   15.29 km/h
        Direction:       337.5 °

So I don't think those will help a lot for my Weather station Utrecht Overvecht.

A posting about reading 433.920 MHz signals triggered the idea I had ages ago to decode those signals and see what weather stations are available nearby. The original posting 433,92Mhz ontvangen (Dutch) was about receiving remote controls (KlikAanKlikUit) and had a screenshot of some Linux software for receiving those signals but no name of the software (that would be useful information).

But a simple google search found me rtl_433 on github which receives and decodes all kinds of signals on 433.922 MHz.

I downloaded it on the raspberry pi for radio experiments, and it is working fine receiving weather information from probably nearby weather stations. At least one outside temperature and humidity sensor, one inside temperature and humidity and one wind and temperature sensor. This last one could be nice for my weather station!

2017-01-27 21:00:27 :   HIDEKI Wind sensor
        Rolling Code:    15
        Channel:         4
        Battery:         OK
        Temperature:     3.6 C
        Wind Strength:   5.31 km/h
        Direction:       67.5 °

and a rain sensor:

2017-01-27 21:01:05 :   HIDEKI Rain sensor
        Rolling Code:    0
        Channel:         4
        Battery:         OK
        Rain:    648.2 mm

Thanks for sharing, neighbours!

The wireless card of the weather station computer in the shed is dual-band but with only a 2.4 GHz capable antenna. Since the house access-point is configured to support both 2.4 GHz and 5 GHz channels the system sometimes selects the 5 GHz access and keeps having serious packet loss. I looked at ways to convince the driver to select 2.4 GHz channels only but found none, but then I found out wpa_supplicant can do this. But I configure wpa_supplicant through wpa-* options in /etc/network/interfaces so I had to find out how to configure it using those. The manpages for the interfaces file is very limited on the wpa-* options, but I found an explanation that a lot of wpa_supplicant options are supported, including the one to select frequencies. The sneaky part is that the option in wpa_supplicant.conf is freq_list and the option in /etc/network/interfaces is wpa-freq-list. A rather complete list can be found at Where can I find a full list of wpa-* options for the interfaces file? - superuser.com. So now I have in /etc/network/interfaces:

auto wlan0
iface wlan0 inet dhcp
        wpa-ssid default
        wpa-psk VerySecret
        wpa-freq-list 2412 2417 2422 2427 2432 2437 2442 2452 2457 2462 2467 2472

The ideal solution is to order a dual-band (2.4 GHz and 5 GHz) antenna.

Update: Noticeable absent are channels 12 and 13 which are available for regulatory domain NL but are not listed when I ask the driver for available channels:

koos@ritchie:~$ /sbin/iwlist wlan0 chann
wlan0     19 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 52 : 5.26 GHz
          Channel 56 : 5.28 GHz
          Channel 60 : 5.3 GHz
          Channel 64 : 5.32 GHz
          Current Frequency:2.462 GHz (Channel 11)

And now I wonder why those are missing.

Lightning strikes counted today

Finally a thunderstorm passed our house today, and it got counted on the lightning strike detector!

The downside is that switching the light on in the shed a few times causes more 'hits'.

A problem I did not expect to see: a harddisk getting close to being too cold. This disk in the weather station computer in the shed is a laptop harddisk and according to the specs the minimum operating temperature is 5 degrees Celcius, which was reached last week when the shed dropped just below 2 degrees Celcius.

I still had the wish to submit the Weather station Utrecht Overvecht to the APRS network to get the data on the APRS maps and maybe even added to the Citizen Weather Observer Program.

APRS stands for Automatic Packet Reporting System which allows lots of information to be automatically exchanged. The most well-known one is position reporting, but there is a lot more, including weather stations.

It wasn't very hard to get this done, I just had to find the time to do it. The trigger was the mention of a new APRS server in the Netherlands at Amsterdamse APRS server - PA4TW. I played a bit with the perl modules Ham::APRS::IS and Ham::APRS::FAP. Ham::APRS::IS is for communicating with the APRS-IS network. And Ham::APRS::FAP is for parsing APRS packets. I used this module to make very sure my outgoing packets parse correctly before actually submitting them to the network (and still making a few mistakes in the process).

I used the explanation and example at APRSWXNET information by Philip Gladstone to find out what to submit and in which format. The interesting point is that wind measurements can not be omitted, but since I don't have a working wind measuring setup I have to enter the '...' values to show that the measurement is not available. And temperatures are measured in Fahrenheit so I have to convert first from my measurements.

The current outgoing packets look like:

PD4KH-1>APRS,TCPIP*:/161010z5206.6 N\00507.1 E_.../...g...t045h91b10088http://weatherstation.idefix.net/

And now the weatherstation shows fine: PD4KH-1 weatherstation on aprs.fi and Weather stations near PD4KH-1 on findu.com. Note how aprs.fi converts to degrees Celcius and findu.com stays in Fahrenheit.