Archive for the ‘Technical’ Category

TapWeather Station

5 Jul 2021 16:14 by Rick

When I was working on the electric pendulum clock some years ago I was interested to discover how much the simple compensated pendulum was affected by temperature. It was then I discovered how inaccurate domestic thermometers [picture] were. The clinical mercury ones with the markings directly on the side of the stem were, thankfully, good but the ones with the tube clipped into a wooden or plastic holder were absolutely hopeless. You could put them side by side and there could be a discrepancy of three or more degrees, and this even on some so called Factory Act thermometers. I was dismayed to discover that the electronic variety were not a lot better; I purchased an integrated circuit type to install in the clock and I had to calibrate it in software. So I bought a lab thermometer from an instrument supplier which, though not certified, I could trust to be reasonably good and calibrated the other devices around the house. I found that the linearity on all of them was good and even the delta wasn’t bad but it was the offset which was at fault in most cases—the tube was not fixed into the holder in the right place. This was also true for the electronic ones that they were not calibrated, even roughly, before shipping. One of these, 1.5deg out, was intended to test the temperature of a baby’s bath water.

This last birthday I was given something I had a mild yearning for for some time – a home weather station. The remainder of this post is my experience with setting it up and using it. The model I was given, the same as my daughter-in-law, is a Bresser WiFi colour 5-in-1, which is also known in America under the brand name Logia. It comes as two parts – an outside part containing the sensors and an inside display (also containing its own temperature and humidity sensor) and that communicates to the outside part by radio signal (868MHz UK, different frequencies elsewhere) and to the internet by Wi-Fi. It is described as a colour display but this is a bit disingenuous as the colour is a fixed back image with black LCD lettering overlaid!

Now, if you are following this with a view to installing your own, I strongly suggest ignoring the paper instructions that come with it and downloading the American Logia instructions. They are much much better than even the English/German online version available from Bresser. There are small faults in all of them but the American ones are much more comprehensive. In particular you can ignore references to a USB cable (there is no socket), solar panel and Beaufort scale readings which must refer to another model.

Following the instructions the setup is quite straight forward. First insert the backup battery and power the display using the wall wart before inserting the batteries into the sensor unit. Everything seemed to connect ok and it was good that, with both devices side by side they were reading the same temperature and humidity within a reasonable tolerance.

But now where to locate the sensors? We live in a terrace house so I was concerned that if I located it in the back garden that there would be a wind tunnel effect which would distort the wind direction readings. The other alternative was to put it on the roof but some sources said that the temperature sensors were supposed to be about 1.5-2m from the ground. The instructions were not concerned about that, only that it was far enough away from any surface not to be influenced by it, so I attached a pole to the chimney and installed the device about 2m above the roof tiles. Fortunately this was fairly easy as we have a valley roof which is easy to access safely. There were a few snags to this—I first tried to install it part way up an existing aerial pole but that is not possible as the housing bulges out and gets in the way. Then I discovered that you can only mount to to one side of the pole as what they call the pipe clamp would only fit one way round—a careless fault caused by the rod not being symmetrical. Thirdly I tried to install it on a horizontal TV aerial mount (as the instructions suggest) but it is then not possible to align the device to point north without moving the mount which would misalign the TV aerial. So eventually I had to install a new pole on the other chimney. I estimate the the device is now 12m above ground level which becomes important later.

The next thing to do was to register with either or both of the weather aggregator services that you wish to use— and/or—for this it is best first to discover the exact location of your device, latitude, longitude, elevation above sea level and the height above ground level as you only get one chance to do this without starting again. There are web sites that help you do this such as Google Earth. When you register they give you a device name and a passcode which you need in the next stage. There is no published API so it is not possible to do your own logging of readings for local analysis however the Weather Underground site does report back very detailed readings on demand. It is generally better than the Weather Cloud site though the phone app is not very good.

Finally to attend to the display and communications device. The range of the radio communication is good so there is a strong signal two floors down between the parts. Connecting to the internet and the weather sharing websites is a bit unusual. What you need to do is put the display into Access Point mode by holding down one of the control buttons. Then it becomes its own Wi-Fi station which you can connect to using any device with Wi-Fi and navigate to a fixed IP address from a browser. I wouldn’t recommend a phone as you need to enter some complicated passwords very precisely. A device on which you can easily copy and paste is best. If you need to make any alterations then you need to re-enter this AP mode as it is not possible to communicate with the device once it is on your house Wi-Fi.

The display device is a bit idiosyncratic. Some controls are on the front panel, which in my opinion would work better on a touch screen, and some are on the back. For example to change between Fahrenheit and Celsius, or inHg and hPa for barometric pressure, there are switches on the back but to change between km/h, mph or knots for the wind speed is done by holding down the wind button on the front for a few seconds. A small fault with the display is that in low intensity mode it flickers but it is fine at full brightness (though not in a bedroom). There is little information about what the perception readings (Feels Like, Wind Chill and Heat Index) actually mean and no explanation of Dew Point and its relationship to Humidity so you would be best to look these up on Wikipedia. The display device will also function as an alarm clock but I don’t see the point of that.

How well does it work? Following my earlier experience with thermometers I was pleased to discover that the temperature measurements are pretty good. As far as I can tell the wind speed and direction, and the rain gauge match what is actually happening and accord with weather reports. Barometric pressure is another matter which needed further attention below. At first sight I thought the device was German and translated for marketing in the UK and USA under the Logia brand but now I am not so sure. The online reporting is excessively precise giving, for instance, two decimal places on the hPa, Celsius and mm rainfall readings but big jumps between actual values suggesting a much lower resolution. This may be because the actual readings are in imperial measurements (inHg, Fahrenheit and inches) then converted. Or is this just because the web sites require imperial measurements? There is also the evidence of the much better Logia manual.

I have found that on my unit the baro readings were very inaccurate—under reading by 8 hPa all the time. Yes, I can mentally compensate but that doesn’t put it right for the internet aggregators. At this point (while doing this write up) I discovered the Logia instructions, and these detail an advanced calibration mode. On there you can adjust offsets for all the measurements and it also tells you the firmware version in case it needs updating. The difficulty comes in finding accurate values to calibrate to. The nearest official station to my home is about 10km away as the crow flies so may not have the same weather as here. Trusting that, at the moment, the air pressure doesn’t vary much over a region, I have confirmed that it under reads by 8hPa. Now to do the calculation to allow for altitude is a very complicated equation but an approximation can be assumed to be 12hPa per 100m elevation for most UK populated areas and there is an online calculator—coincidentally(!), for 70m above sea level the offset came to 8.38hPa—so perhaps the device is calibrated for use at sea level? The Logia manual does say most calibration values won’t need changing “with the exception of Relative Pressure, which must be correctly calibrated to reflect your distance above sea level to account for altitude effects.” Doh, why didn’t they make this clear in the first place—the Bresser manual doesn’t even mention that you can do it.

My early conclusion is that this is a very well made and reasonably accurate device rather let down by poor documentation. In particular, with no mention in the UK manual to compensate for altitude, there will be a very high proportion of devices reporting completely wrong weather readings. My house is only 60m above sea level, the readings will be ridiculous for people on high ground.

Update: 10 May 2022

My device now seems to be broken in two respects, fortunately I can get around them. In theory I could return it under guarantee but that would be too much of a nuisance. This seems to have happened about 6 months ago as that is when Weather Cloud reported that I went off air (but didn’t notice until recently)—and I can’t seem to get back on. It accepts the code but doesn’t update. The second failure I know happened around that time and that is the offset between absolute barometric pressure and relative isn’t calculated correctly. I tried updating the firmware but that made no difference. I have worked around that by putting in a false offset which gives the correct results—both on the screen and reported to Weather Underground.

It is now clear (and obvious really) that the barometric pressure sensor is contained in the base station not the remote device. So when calculating the offset required by altitude, it is that height that you should use— about 6m difference in my case.

One of the weaknesses of these devices, at least this model, is the difficulty and lack of instructions for setting the pressure offset. It would be much better if they just required you to input the height above sea level into the device and it to work out the offset for itself. It looks like most people get it wrong. I did a quick look on Weather Cloud for stations within 5km of my home (currently at 1014hPa by my device and 1016 by the most recent Met Office weather chart). The neighbours that are online are reading 1026, 1010, 987, 1012, 1011, 1014, 1004, 1018 & 1021. The altitude maybe varies by 20m or so.

TapiPhone move from Orange(EE) to Giff-Gaff

20 Apr 2015 17:09 by Rick

This should all be straight forward:

  1. Unlock phone from Orange
  2. 30 days in advance, notify Orange/EE that you wish to terminate the service or transfer the number.
  3. Sign up to Giff-Gaff and activate their SIM
  4. Put in the Giff-Gaff SIM
  5. Use Phone
  6. Get the number transferred

Things are never as easy as that. These instructions may apply to other network moves.

  1. To unlock the phone from Orange go to their web site and you will find instructions if you look hard enough. Basically you have to ring them and pay about £21. It can take up to 28 days. In practice you may need to remind them as they seem to forget; so do it in plenty of time before your contract expires—I would allow at least two months.
  2. If you want to transfer your number then you will need to have requested a PAC from Orange/EE. They do this fairly quickly but subject you to an inquisition first. The PAC lasts 30 days so you can request it in good time before hand. (Edit: I thought this was free but I see from the bill that they charged me £5.65+VAT but I can’t be bothered to quibble.) Alternatively, if you don’t want to transfer the number, then you need to notify them (30 days in advance) that you wish to terminate the contract/service.
  3. The easy bit—just follow the excellent Giff-Gaff instructions.
  4. Now the hard bit. They say just take out the old SIM and put in the new activated one. On an iPhone it doesn’t seem to work as easy as this as the phone still thinks it is on the EE network and refuses to recognise it. The only way I could get it to work was:
    1. Connect the phone to your computer running iTunes.
    2. Do a full backup of the phone to iTunes (not iCloud).
    3. Eject the phone from the computer.
    4. On the phone, go to Settings ==> General ==> Reset ==> Erase All Content and Settings—scary I know.
    5. Switch the phone off and remove the old SIM card.
    6. Insert the new Giff-Gaff SIM card and switch the phone back on.
    7. Connect the phone to the computer again.
    8. Go through the new phone setup process and when it gets to that point, restore from the backup you just made.

    It will do that quite quickly and then reboot, but now it will go into Sync and restore everything else. This takes quite a while (depending on how big a phone you have).

  5. Use the phone
  6. If required then you fill in their number transfer form and that only takes a day but you will be without any service (except Wi-Fi) for a few hours and you may need to re-boot the phone.

TapSuperscript for WordPress

26 Mar 2015 22:10 by Rick

When editing WordPress pages or posts there are a number of buttons in the editor to make things a bit easier; Things like Bold, Italic, Blockquote etc. There are in fact a lot more built into the editor than are actually shown in the menu bars. I rather like having superscripts and subscripts come out properly so I have allowed for it in my themes; things like 2nd and H2O. To make these easy to edit I have crested this little WordPress plugin – RJP-Superscript. Just add it to wp-content/plugins on your site and activate it and new buttons Sup and Sub will be enabled in both the Text and Visual editor (in the Visual editor, click the “Toolbar Toggle” on the end of the first line to reveal the second line of buttons). It can’t do magic though—if your theme doesn’t style super and subscripts then nothing will happen in the finished post.

TapJava 8 problems

11 Mar 2015 14:23 by Rick

There don’t seem to be many reports of this but Java 8 was a significant change from v7 and I have found at least two programs that no longer work. It is particularly difficult as the programs concerned are not actively maintained any more so there is little chance of getting the developers to make changes to allow for the new release. The problem seems to be that Java is now installed in a different place—dependent on the version number. I am testing using version 8u40

The programs concerned are

  • EasySearch v3.0.4 running on WinXP (download not working). The only fix I can find for this is to remove Java 8 and install an old version 7u76 and also force it not to update (Control Panel >> Java >> Updates). I needed the JRE x86 offline version. Java 8 had been saying that some things won’t work in Winodws XP for a while but I wasn’t expecting it to be this serious. There is the same problem under Win7 running EasySearch in XP compatibility mode.
  • YawCam running on Win7. There is a work-around for this one. Apparently the new way to find java is via \ProgramData\Oracle\Java\javapath but something this program does doesn’t work with this so you have to use the old style path which is \ProgramFiles(x86)\Java\jrel.8.0_40 . I would have reported this but the forum registration is not working.

JavaRanch [sorry, I lost the link] is reporting a similar problem.

Java doesn’t like to be told not to update—in fact it seems to ignore it and keep nagging you.

TapWordPress Exploit Scanner

5 Mar 2015 09:11 by Rick

The WordPress Exploit Scanner was a very useful WordPress plugin that would check your site for interference by hackers. It does this by checking the hashes of all the modules against what they were when the code was published and also looks (as best as it can) at your posts and comments database looking for common inserted exploit code.

Unfortunately this seems to have stopped being updated for the last two versions of WordPress (4.1 and 4.1.1).

All is not lost though as all that is missing are the current hash files and Philip John has stepped forward and is hosting replacements – just that it is not as slick as before and these files need to be manually uploaded. The procedure is as follows …

  • Go to
  • Find the relevant hash file based on the version of WordPress installed. Currently this is hashes-4.1.1.php – left click on this link.
  • This generates the required hashes file in a window. The easiest way to download it is to click on the “Raw” button
  • Select the whole page (CMD-A or CTRL-A)
  • Copy the whole page (CMD-C or CTRL-C)
  • Open a text editor (e.g. textedit or notepad)
  • Paste the page into there (CMD-V or CTRL-V)
  • Now save the file and call it (in this case) hashes-4.1.1.php – note: it must not have .txt added on the end!
  • Upload this file using FTP to the web site into directory wp-content/plugins/exploit-scanner
  • Login to WordPress as admin
  • Go to Tools ==> Exploit Scanner
  • Click “Run the Scan”

When I did this on a very clean site (no other plugins, very little content) the number of warnings was down to two, both of them in the exploit scanner itself. In practice you will get more than this as it doesn’t know about other plugins and accidental false positives but with care and experience it is very readable.

TapNot all USB chargers are made equal

26 Apr 2014 16:35 by Rick

Well, we sort of knew that. Some devices like more power to charge faster so their dedicated chargers will give more power—the iPad is a case in point. But you would think they they would all provide up to their rated power to any device that asked for it. No.

All figures are in amps drawn. Blanks are not tested. “X” indicates it refused to play.

iPad iPhone 4 HP Slate 7 LG Phone Garmin
iPad charger 2.0 X X 0.48
iPhone charger 0.85 0.95
HP charger 0.9 0.85 1.0 0.35
Camelion charger 0.9 X
Maplin Travel charger 0.9 X

My conclusion at the moment is that the iPad charger refuses to charge most non-Apple devices (it is outside the USB specification anyway). Also that the Slate 7 is slightly fussy about which charger it uses.

You have to be careful which chargers you take on holiday if you are traveling light.

TapCall Blocking on an iPhone

12 Jun 2013 13:57 by Rick

There are a lot of web articles saying that you can’t block numbers on an iPhone without Jail-breaking it. There are apps around that say that they can do it but they don’t work because Apple doesn’t allow apps to access the phone part of the device. However there is a way which is not too difficult to achieve.

What you need to do is create a contacts entry called for example “Blocked”. Assign to this all the numbers that you require to block. Now assign a unique ring tone to that contact (the “Old Car Horn” is a good one) and you will know immediately when an unwanted call comes in. To go one stage further, without too much difficulty you could create a silent ring tone and use that. Then you will never know when the annoying caller rings you. If you later discover that it wasn’t a caller that you wanted to block then remove it from the contacts list.

TapBBC iPlayer won’t play downloaded program

14 May 2013 09:31 by Rick

This fix relates specifically to the Mac desktop version of BBC iPlayer running on Mountain Lion (Mac OS X 10.8). It may work for other versions but I don’t know.

I will post the actual error message next time that it occurs but it relates to when iPlayer displays the station intro but then says something to the effect of “unable to play downloaded program”—usually one that has been waiting a week or two. It then immediately deletes the item from the repository.

The fix is as follows.

  1. Quit BBC iPlayer.
  2. Recover the program(s) you have just lost from backup—preferably Time Machine as that is more likely to be up to date. The location of the programs is ~/Movies/BBC iPlayer/repository and it is the items that start “b01” that you want.
  3. Go to ~/Library/Application Support/Adobe/AIR and move the directory “ELS” to trash. If you can’t see ~/Library then see this article.
  4. Now Restart BBC iPlayer and the program should work.

One oddity is that all the expiry dates will now be well into the future but don’t believe it: they will expire just as before so watch them soon.

TapVMware Fusion and Windows Safe Mode

2 Sep 2012 21:42 by Rick

To get Windows into Safe Mode for some housekeeping functions the (reasonably) well known method is to hit F8 during the boot sequence to obtain the start-up menu. When you are running Windows under VMware Fusion on a Mac then this is not as easy as it sounds. Different Macs do special things with the function keys across the top of the keyboard—it is something that is not standard across different models. Sometimes F8 does brightness and other things. On my Mac Pro with wired keyboard F8 is marked as Play/Pause and most times kicks iTunes onto life. It does this whether the keyboard control is assigned to VMware or not. The various help guilds you get by searching the internet say to un-tick the “Enable Mac OS Host Keyboard Shortcuts” in the preferences but that doesn’t seem to be enough. The only way I could get anything to work was to go to Key Mappings and assign an unused “F” key to be F8 (fortunately the keyboard has 19 of them to chose from—I used F16).

TapMicrosoft – Nanny knows best?

24 Apr 2012 09:40 by Rick

Do you like to keep a few shortcuts on your desk top? Those things that you need often or might need quickly, or those in obscure places that are hard to remember. I do. I don’t like a cluttered desktop but there are some things that are easier there. I have links to stuff on networked drives (that maybe require a mount or VPN before they are visible), links to utility programs like KeePass and PuTTY and some scripts that do routine things.

Microsoft in its wisdom (Windows 7) has decided to clean these up for us on a regular basis and if they are broken or not recently used then “tidy them up” for us—i.e. delete them. It wouldn’t be so bad but there are bugs in it, so it often deletes stuff that is frequently used and are not broken by any definition. This is not directly configurable, you have to turn off the whole of the maintenance daemon but it is not a great loss. Open the Control Panel and go to Troubleshooting (or System and Security—Find and Fix Problems on some systems). Now select the Change Settings in the left margin and switch it off. Done.

You can run it manually occasionally for the other benefits—same panel at the bottom is Run Maintenance Tasks. On the panel that pops up first click Advanced at the bottom and un-select Apply Repairs Automatically. The other things it does is check logs that may be wasting disk space, that the system time is set correctly and looks for disk errors. The last is the only really useful one.

Addendum: I notice that it also affects entries in Programs\Startup as well!

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