Becalmed

Through every nook and every cranny
The wind blew in on poor old Granny

Spike Milligan

Tree branches thrashed, clouds scudded across the sky, little old ladies were twirled down the road and my weather station's anemometer cups were a blur; truly it was windy day. Wind speed: 0 mph reported the Vantage Vue's console. Clearly there was a problem, and I had suspected as much having noticed a suspiciously long calm period being reported on Weather Underground. Oddly, an occasional gust would be recorded but only once or twice a day.

After some internet searches it was clear that this was quite a common problem, with most fingers being pointed at the anemometer cups coming loose from the metal shank on which they're mounted. The cups spin round but the shank, which is attached to a magnet that activates a reed switch, remains stationery. As I saw a measurement every now and then I assumed this would be the cause. It was that or the failure of the reed switch. I would need to retrieve the Davis Integrated Sensor Suite, or ISS, and have poke about in its innards.

Inside the ISS

In an earlier blog post Weather Station on a Stick described how I mounted the ISS on the end of an aerial pole that was itself attached to the side of a shed. To save myself a trip up a ladder to remove the ISS, I loosened the pole from the mounting bracket on the shed and carried the whole lot, like a head on a pike, to a table for dis-assembly. Whilst I had the ISS down I thought it would be a good opportunity to clean it, so I fetched some warm water with detergent in it and a cloth.

Before I went any further I checked whether the anemometer was slipping on the metal shaft: it was firmly attached. Bugger - that meant it was likely to be a problem with the reed switch.

ISS Ready for Surgery

My first task was to remove the white shielding that protects the thermometer sensor, which is made from 5 separate plastic plates held together with long screws. All sorts of crud had accrued between the plates, along with a cohort of spiders that marched off, with as much dignity as possible, to find new homes. If you plan on doing this take a moment to note which way the plates are orientated - they will only go back one way and it's amazing how many different combinations you have to try if you didn't pay attention to this at the start.

The next step was to unscrew the rainfall measuring spoon (Davis's term) which is the triangular unit between the wind vane and the mounting bracket in the photo above.

Level spoonful of brown stuff

The spoon itself had accreted a coating of dirt - it's amazing what you find in rain these days. This was surprisingly stubborn to remove and needed a good bit of rubbing with a cloth to clean. I took the opportunity tounclip and clean the rain collector filter that was also becoming encrusted.

I then undid the four screws that held the top and bottom of the ISS together. When pulled apart they revealed, well, not a great deal.

Nothing much to see here, move along

The inside was remarkably clean, considering it had spent nearly two years outside; a testament to the quality of the casing's weather sealing. My main concern was the reed switch, which was hidden inside the black box on the left of the picture. To open the cover of the box I had to unclip it from the main bottom moulding by squeezing the sides of the cover. With the cover off I could then get to the reed switch and replace it with a new one. Ah...

You can't mess with me

I didn't expect that, but it makes sense for the delicate bits to be well protected. Not wanting to break the sealed plastic cover to take out the circuit board I flicked the reed switch (mounted in the bulge at the top) a couple of times with my finger in the hope that that would loosen it should it have stuck. Looking at the top part of the ISS's casing that sits above the reed switch I could see the magnet at the end of the anemometer's metal shaft; the wind spins this, actuating the reed switch, the opening and closing of which is counted to calculate wind speed.

Anemometer magnet - Spinning but no-one's receiving

The magnet rotated when I turned the anemometer cups by hand, so that was OK too. My final hope was that I'd somehow unstuck the reed switch, so I reassembled the (now much cleaner) ISS, attached it to its pole and the pole to its bracket.

No change. There was still no wind speed reading and it still only recorded a gust two or three time a day; professional help would be required. I knew the Vantage View was way out of warranty so I looked at the support pages of Prodata, the company I had purchased it from, to find out what my options were. In short, limited. Davis servicing and repairs for the UK are dealt with by McMurdo Ltd in Portsmouth who I would need to phone or email prior to returning the whole ISS unit.

During the period the ISS was away for repair there would be no weather recording - not that this would be a huge blow to UK meteorology - but I'd miss it. So, I demurred, hoping to find an alternative way to rectify the problem.

Time is the Great Healer

It's now working. The wind speed is constantly updated and gusts are recorded correctly. How did I achieve this? By doing nothing - it just started working again, about a month after I'd dismantled it. I still don't know what was wrong with it or how long it will continue to work; time will tell.

Weather Report

My weather station has been running virtually without a hitch for several months. The few problems I had encountered with the weewx software running on the Raspberry Pi had been ironed out (due to my errors, not the software's - see posts passim). The Pi has occasionally frozen and needed a reboot, but for a £30 device running 24/7 for months on end that's remarkable. It would be stupid to mess with it; best leave well alone now it's stable.


A Silver Lining in Every Cloud

No, of course I couldn't leave it alone. About two years ago I had a Maplin weather station feeding data to Sandaysoft's Cumulus software that was running on a Windows PC (see Where's the Time Gone). Whilst I liked Cumulus I wasn't prepared to leave the PC running in order for it to upload regular updates to the website, due to the noise it generated and the power it consumed, which is why I moved to the Pi. I always wanted to use Cumulus again and had considered building a mini PC using a low-power CPU and mini-ITX board. However, although mini-ITX motherboards are relatively cheap, by the time a hard drive, memory, a case and Windows, annoyingly the most costly component of all, had been added, the total cost had become eye-watering.

That would have remained the status quo were it not for my daughter complaining that her laptop had starting misbehaving: a blue screen of death that ultimately required a restore from a backup. Then the 'e' key stopped working; which causd hr quit a problm as it's th most common lttr in th languag. My suggestion of only using words without an 'e' didn't go down well and she resorted to using an on-screen keyboard until her new laptop arrived.

There are no problems, only opportunities, as some management wnkers (sorry, the 'a' key's playing up now) are wont to say. I realised I could use her old laptop as a way to run Cumulus; it would be quiet and fairly frugal with power too. Better still it had a large hard drive so it could also be utilised as a media server.

Cloud processing - Laptop running Cumulus software

Speculate to a Cumulus

After I had rebuilt the laptop from the factory image (then removed the cruft and bloatware that was included - I'm talking about you, Dell) I downloaded the latest version of Cumulus, 1.9.4 build 1085, from the Sandaysoft website. Cumulus is donationware: free to download and use, but you're encouraged to give the author some money to at least keep him in tea and biscuits. Considering the polished nature of the software, its features and the level of support that Steve, the author, provides it would be churlish not to donate something (I have). Although judging from a couple of justifiably testy comments Steve has made in the forum, many people are too cheap to do so (but probably still expect him to sort out their problems).

Like any weather software worth its salt, Cumulus doesn't just provide a regularly updated display of information from the weather station, it also includes FTP to allow the data to be uploaded to a website. A set of quite attractive web pages are provided (although the graphs are rather ugly) and the tags (used by Cumulus to embed the weather data into the web pages) are documented so you use the ones you want and design your own web pages. Simply put, to create the web pages the program uses template pages that it processes by embedding the tag data and then FTPing the resulting page. So, for example, the tag #temp is replaced by the temperature reading from the weather station. The Webtags page in the Wiki explains this in some detail.

There isn't a manual for Cumulus but there are a fairly comprehensive set of instructions on the Cumulus Wiki, plus there's a forum that's well frequented by knowledgeable weather enthusiasts and Cumulus users.

Once again I used the web server on my trusty old QNAP NAS to make the information available to the whole wide world. And if that wasn't enough, regular updates are being sent to Weather Underground, whose pages are rather attractive and have some cool graphs too.


My Cam and Yawcam Too

Something else I had wanted to do for a while was reinstate a webcam feed. For some time my Raspberry Pi had happily processed images from a Logitech C270 webcam as well as running Weewx. Unexpectedly I started seeing problems with both Weewx not running and the webcam images not being uploaded; I have no evidence for this, but I suspect this corresponded to changes in Raspbian to accommodate the Raspberry Pi camera. My Pi is an early (not the earliest) Model B, only has 256Mb of memory and possibly struggled with the demands expected of it.

A Windows OS meant I was able to use Yawcam again. This is a neat, unassuming and free program that will take a feed from a webcam and send images, either still or streaming. I use it to grab an image every 10 minutes and squirt it to my web server where it forms part of the weather webpages on my site and Weather Underground.

Points on a Curve

At the time of my last post I still had a problem with the daily weather graphs that weewx was creating. They were a series of dots, rather than a continuous line like the graphs for weekly, monthly and yearly data.

One of the beauties of weewx is its tweakability (technical term) and my first thought was I may have bolloxed up (there's another) a setting in the skin.conf file that sets how graph data is presented. Display type is set to line at a high level and you can change this for each graph if you choose; checking this showed it was set to the default. Eventually, by chance, I saw a post on the weewx User Group that explained the reason for this was too large a gap between the data updates. When I configured the Vantage Vue console I had set the archive interval to 30 minutes and this was too wide a gap to cause a line to be drawn.

Weewx offers a tool to find the current settings on the console (wee_config_vantage --info) and then to change them individually: --set-interval=SECONDS was the one I needed, where 'Seconds' was to be 600, i.e. every 10 minutes. Could I get it to work, could I buggery. Syslog told me that it couldn't talk to the console (between providing updates, proving that it could). Eventually I resorted to plugging the console into the PC, firing up Weatherlink and doing it that way. Success! The graphs starting showing a solid line, rather than individual dots.


Port Is Dead

All was well for a couple of days when I noticed at 6:30 (up early to catch a train) that the website hadn't updated since midnight. Puzzled, I logged onto the Pi that evening expecting to find that a power cut had changed the IP address of the NAS but found the Vantage Vue console had been reallocated port dex/tty/usb1, instead of /usb0. Not finding the console on the port in the weewx.conf file Weewx had sulked. I changed amended weewx.conf to look at usb1 and all was well for a while. Then everything failed again.

When I checked the syslog it seemed that the webcam was causing a problem with the USB hub and it was endlessly trying to register with the OS. Resolution? I've unplugged the bloody thing until I've time to work out why it's decided to fail after working perfectly for months.

As an aside, one of Weewx's tasks is to send data to Weather Underground. Somewhat scarily the day that Weewx had gone down I had an (automated) email from them to say that they hadn't received any data for over two hours. Once I had Weewx back up that evening I had another email to say they had started to see data again.

Weather Station on a Stick

Shortly after I wrote the last post the Davis Weather Vue weather station I had ordered was delivered. Inside the box was the console (a small unit with an LCD display and some buttons) and what Davis calls the Integrated Sensor Suite, or ISS (a single white and black plastic unit housing rain gauge, anemometer, wind vane and thermometer). There was also a plastic bag that contained a mounting kit, battery and a teeny tiny Allen wrench so small I thought it was something you could use to poke into the Reset holes present on some consumer electronic equipment.

Along with the Weather Vue I had ordered a USB Data Logger, which was supplied with Davis' WeatherLink software. This is an extra - the Weather Vue will function happily without it - but I wanted to export the data to my Raspberry Pi and a Data Logger was required to do this. Prodata had thoughtfully attached detailed instructions regarding installation and preparation of the software. Presumably they had had plenty of questions from users about it in the past. Depressing, though, that the software and Data Logger hardware hadn't had the difficulties designed out.

Assembling the ISS was trivial. The instruction booklet was well presented and clearly explained how to insert the rain tipping spoon (their word), attach the wind cups and wind vane. The ISS has to be mounted on a pole, so I bought an aerial mast which, at 3cms was about the recommended diameter. Prior to mounting it I tested that it was communicating with the console and then attached it to the mast and the whole lot to the bracket that had formerly held the WH-1080. A nice touch was the spirit level built into the top of the ISS to help ensure it is level.

Ugly, though, isn't it?

Consolation Surprise

The hard part done I turned to the console. To my chagrin I realised that although it had been supplied with a mains adapter it also required three 'C' size batteries. These weren't available in either of the shops in the village and so I had to trek into the nearby town. Once procured and inserted I switched on the console which was meant to run through a self test and beep four times. I lost count after about the twelfth beep and was becoming somewhat concerned at the random messages on the screen and constant reboots.

Eventually the console settled down and I was able to start the setup process which, apart from finding elevation, latitude and longitude (Google Earth is your friend here), was pretty much a case of accepting the defaults. Once complete the latest data from the ISS is displayed together with astronomical events - I was pretty impressed to see it show that the Taurid meteor shower was due.

All this, and more

By pressing one of the buttons on the console it's possible to obtain more information about, say, the wind as well as displaying the data in the graph in the bottom left of the display. At present I've only scratched the surface of the information it is possible to display.


Web Weaver

The next stage was to link the Vantage Vue to my Raspberry Pi and upload the data to a web site. Firstly I installed the WeatherLink software that had been supplied with the data logger onto my PC which enabled me to test that I was able to download data from the console. This worked without a problem so I installed the latest version of the excellent Cumulus software, again I was able to receive data with no errors.

Being unfamiliar with weewx (and somewhat shaky with Linux) knowing that the hardware worked meant one fewer place to look if it didn't work. The beauty of weewx is that it's pretty easy to set up, offering two ways to install itself (via a package or from a downloaded tar file); both methods are explained in the docs section of the weewx website. I opted for the tar file method as it installs all the files in /home/weewx and it seemed easier to have all the gubbins in the same place.

After weewx was installed I had to edit the weewx.conf file to set the altitude, location and weather station type. This step is well documented in the docs and I used Leafpad on the Pi via an Xming session to make the changes. Yes, yes, real men use the command line, but I don't care. An extract from the weewx.conf file is shown below.

Easy peasy configuration file editing

The part that had me scratching my head was the FTP sections - crucial to get right if I wanted to see the data on the web. For the server name I first used the local URL of my web server (actually a Qnap NAS) and this failed. Eventually I had success by using the IP address of the NAS.

After I had finished fiddling about I started weewx and watched the log with crossed digits. Everything looked good, especially the FTP upload, so I opened up the webpage and was rewarded by data from the weather station and a selection of graphs. As my confidence editing weewx's index.html.tmpl file grew I added a feed from the webcam and satellite information from Meteox. This is the final result or you can peruse the half-hourly feed to Weather Underground and The Met Office Weather Observation Website (WOW).

So everything's sweetness and light. Well, not quite. I have an issue with the daily graphs in that they plot points and not lines; oddly the graphs for monthly data correctly show lines, dunno why the daily graphs don't. Before I ask on the weewx forum I want to eliminate the obvious.

Beeching Axe

I had been finding it increasingly difficult to make compromises with what I wanted to do with the railway layout and the space available. Ideally I wanted to be able to set up a train consist (as our North American friends call it), set it going around the layout and then I could do some interesting shunting stuff in the station yard. This concept had worked on a layout I had built some years ago, but then I'd had much more room.

Raised track at the rear of the layout (see posts passim) was created to provide some scenic interest; the idea was to create an illusion of mainline running tracks separated from the station area by the difference in height. However the inclines were starting to cause difficulties with train running and it was clear that it would cause difficulties scenically too. Ironically it was lack of space that was the reason for the failure of this idea.

Unsatisfactory. That was my view as I tried to fit the quart of ambition into the pint glass of baseboard. In the end I decided to dismantle the whole lot, baseboards included, and have a fundamental rethink. Whatever I decide to do, it will have to be built in the attic as there's no room in the house for what I want to do. Before that happens some kind of flooring and insulation will need to be installed to prevent my frostbitten (or, depending on the season, roasting) foot coming through the ceiling.


Weather Report

Nearly a year ago I wrote about using a Raspberry Pi to upload weather data from a Fine Offset WH-1080 weather station to a website. For the most part the WH-1080 has worked well and has been a worthwhile introduction to weather data collection. At the time of writing the WH-1080 is being sold in the UK by Maplin for a whisker under £60 (product code N96GY).

There have been some hiccups with interruptions in data transmission from the outside unit. Prompted by an outage lasting over a day I bought a replacement transmitter, only for the original unit to start working again. It's still prone to occasional dropouts, seemingly without any correlation to weather conditions or invertebrate infestation. The latter stopped the anemometer until I was able to clear the spider webs.

Weather Station and Spider Habitat

Presently, however, the unit isn't recording wind speed or direction data. The receiver unit shows changing wind direction but not the wind speed, and neither are being uploaded to the website. This isn't just an issue with pywws, the Cumulus weather software isn't receiving the data either. Dismantling the anemometer showed nothing apparently wrong with it; not surprisingly as all that's inside is a reed switch and a tiny magnet. As repair wasn't possible I ordered a new unit from Maplin. And I'm still waiting for it. The buggers have taken my money (£5 with postage!) and it's still 'on order'.

Finally I decided to order a Davis Vantage Vue weather station and data logger from Prodata, who are selling them together at a 'special offer' price. The Vantage Vue consists of a combined sensor unit containing rain bucket, anemometer, wind direction, temperature and humidity sensors. Like the WH-1080 the sensor data is transmitted wirelessly to an internal console with an LCD display. An optional USB data logger is required to store data and send it to a PC. My plan is to use weewx, a linux-based weather software application, installed on the trusty Raspberry Pi in place of pywws (this program won't work with the Davis unit).

Presently I'm waiting for the thing to be delivered (every noise outside sends me to the window to see if the courier has arrived) and when it is, I'll document how I set up both it and weewx more carefully than I did for pywws and the WH-1080. I'll spare you the unboxing, though.