Category Archives: Battling with Tech

How to do things with your gadgets – usually learned the hard way

Transferring data using Bluetooth

In an earlier post, we suggested transferring data from an Android phone to a Windows computer using the USB connection.  The beauty of this system is that you can manage the filing system on the phone using Windows File Explorer, which is a quick and powerful system.

File transfer system

But since most phones and computers now have Bluetooth, which is a wireless system, why not use that, instead of faffing about with cables? The answer turns out to be that Bluetooth doesn’t give you access to the filing system on either machine.  There is only a file transfer system, and a mighty slow one at that.  Indeed, it is somewhat hidden from view, perhaps to discourage its use.

The procedure is as follows.  Firstly pair the phone and computer using Bluetooth in the usual way.  Then, on the computer, go to the icon box at the right-hand end of the task bar and left-click the Bluetooth icon.  Select ‘Receive a file’

Now go to your phone and find the file you want to send.  So, to send a photo, select your photo viewing app, in my case ‘Gallery’, and click on the share icon.  Select the Bluetooth icon in the share destinations and you should find your computer name there. Start the sharing process.  On the computer, you will see the files coming through (you can share an entire folder).  It’s pretty slow, but once the files have come through, you can browse to a suitable folder on your machine and save the files there.  I doubt you’ll want to do this except when you don’t have the cable handy.

I have not tried doing this in reverse, but I assume a similar process will apply.

Other uses of Bluetooth

I have been trying to find out what else you can do with the Bluetooth connection.  You can tether the phone’s mobile data connection to your computer using Bluetooth or Wi-Fi.  I’ve always found Wi-Fi to be easier to set up and use.

I have also found that with Bluetooth you can set up something called a personal area network, although I’ve no idea how you’d use this.  It doesn’t appear in the Windows File Explorer list of connections and doesn’t give you access to the filing system on the phone.  It seems that the capabilities of a personal area network are dependent of the ‘Device profiles’ of the two connected devices, which are most likely to be specific types of peripheral rather than two computers. I suspect that Bluetooth is mainly intended for ‘simple’ communications between the device and a peripheral such as a keyboard or headphones.

Here for the long-term?

I’ve read some suggestion that Bluetooth might be a technology with limited usefulness and lifetime. I’ve found it difficult to set up – for example I could not link a Microsoft Surface Bluetooth keyboard to a Raspberry Pi.  I suspect that in automating the connection to the Surface tablet, they have made it too device-specific.

Problems of being device-specific

Microsoft do have a track record of doing this.  For example, I use a Microsoft Wireless Mouse and ‘Sculpt’ keyboard, both of which I find brilliantly functional.  However, because I got them at different times, they each need their own USB wireless dongle. This is rather wasteful of the USB connections on my PC and woe betide you if you break the dongle (not difficult because they protrude from the PC) but it doesn’t seem possible to make them use the same one.

This is because the peripheral and dongle have a specific ID code burnt in during manufacture so that they don’t interfere with others you may have in the same office. Perhaps it’s too difficult and a potential security risk to allow users to change this, although it can be done for some Bluetooth sets.

Putting a larger SD card into your Android Phone

If you take much video with your mobile phone, your phone’s internal storage will soon fill up.  You may even have filled up a small SD card and you need a bigger one.  You will no doubt be prompted to get ‘cloud’ storage, but this is not great for storing HD video that you want to view regularly, due to mobile data transfer speeds and costs.

If you google this, you will get hundreds of answers, mostly involving downloading a ‘free’ app.  Some of the apps really are free, but many carry some payload, like advertising or being free to download but needing a payment to use.  Some can carry malware.

In fact, you don’t need an app – your Windows PC has all the capability you require.

I am assuming that you’re only using the SD card to store ordinary (photo and video) files – which is usually going to be the case.  Firstly, using the USB cable, connect the phone to the PC.

Using Windows File Explorer, you should be able to find the name of the phone in the folder list under ‘This PC’. (If you are prompted to select what to do with the device, choose ‘file explore’.)

Double click on the name of the phone and you will see two folders – Card and Phone. [Your phone also has ‘memory’ storage, but this is like RAM in a computer – used by running apps to process temporary data, not for long-term storage.] These two folders represent the SD card and the phone’s internal storage.  Click on ‘Card’ and you will see several folders.

Select the data files you want to transfer – usually DCIM (Digital Camera Images).  Don’t bother with system files like Android, System Volume Information, etc.  These are created by the system and will be put onto the new card when it is initialised.

Create a new folder on your PC and copy the selected files.  This is likely to take an hour or more.  You should copy your DCIM files from both the phone’s internal storage and the SD card.

Now unmount the SD card [to disconnect it from the phone’s storage system], switch off the phone, take the card out, put the new (blank) card in and switch the phone on.

Most (micro) SD cards that you buy will already have been formatted (which means a blank filing system has been created on the card, ready for files to be written to it.) [Android uses the exFAT filing system, should you need to format a card.] The phone will recognise that a new, blank  SD card has been installed and will initialise it for use by copying some ‘system’ information, which will appear in the file called ‘Android’.  On my phone this was mainly a lot of folder names which didn’t contain anything.

Connect the phone to the PC, select the SD card and copy your data  files back from your PC to the SD card.  Again this may take a while.  If you are copying photos and videos, copy the whole DCIM folder back to the SD card. You can’t have two DCIM folders, so if you are copying from both the SD card and the internal storage, then after copying one of the DCIM folders (probably the one with most files) just copy the files from the other DCIM folder and paste into the new DCIM folder.

Using your phone, check that everything you wanted from the phone’s internal storage and the old SD card is now available on the new card.  You don’t need a ‘file manager’ program on your phone, as you can Windows File Explorer to do all this.  Using the phone, check that you find everything you expected using ‘Gallery’ or other Android application that you normally use.

Now, using Windows File Explorer, check the phone’s internal storage and delete DCIM on the internal storage (being totally careful not to delete anything on the SD card that you have just painstakingly updated).

That’s it!  You have now freed up the internal storage on your phone and created a lot more space for all those exciting new videos.  Because it is a slow process, it is probably worth getting the largest memory card that your phone will accept – you don’t want to do this again!

You can, and should, use this system to make regular backups of the SD card.  They last a very long time, but not for ever.

Setting up a new computer

Why get a new computer?

My better half has been complaining for some time that her Dell computer has become painfully slow to use.  I can’t deny that, although I think a lot of it is due to so many apps demanding to phone home when starting up – another curse of the internet age.

It is ten years old and has been upgraded from XP to Win 7 to Win 10.  The specification was decent at the time – an Intel Core 2 Duo processor running at 2.33 GHz and I upgraded it to 4 GB of RAM, running the 32-bit version of Win 10 Pro.

What to get?

She does quite a bit of photo editing and would like to do some video editing, but rather fancied a dinky little rose-gold laptop.  Readers will immediately see a problem here.  Dinky little laptops have dinky little screens and really are only suitable for cloud processing of dinky little documents, as they have dinky little SSD drives.  I decided that the best way of illustrating this was to go on a tour of John Lewis and PC World to see what was available and for how much.

Those pretty little laptops were gorgeously blingy, but their dinky little screens were mainly suitable for web-browsing, writing dinky little documents and perhaps editing some dinky little photographs.

I suppose we could have opted for cloud storage and editing, but that adds another level of complexity. Then we spotted some equally gorgeous laptops with 17.3-inch screens (I imagine that’s a sensible size in cms – yes 44 cm – but is that a sensible size?)  Not something you can put in your handbag, but that already has an iPad and smartphone in it.  We’d initially intended to buy an Asus machine, since we have several good Asus products already, but they didn’t have anything suitable for us to look at in either shop.

Our eyes alighted on an aluminium-bodied HP ENVY-17-bw0003na laptop with 17.3 ” full HD screen. It turns out that there are a zillion versions of this laptop – with different processors and storage options, and it is not easy to be sure which version you are looking at.  In the end we bought one directly from the HP store at a bargain price, as they had a special offer and extended warranty.   It has the 8th-generation Intel Core i7 8550U  4-core processor running at 1.8 GHz base frequency, up to 4 GHz with Turbo-boost. It has a 1 TB hard drive and a 16 GB ‘Optane’ flash memory for storage acceleration. It also has 4 USB 3.1 connectors and gigabit Ethernet built in, and an HDMI connector. It even has a DVD drive, which has already been worth its weight in gold.

So what do we think of it?  It looks gorgeous.  The screen is glossy – glass from edge to edge – but it is beautifully bright and sharp.  The keys are responsive, although cold to the touch (which feels odd).  In normal lighting, they are clearer if you turn the key backlighting off.

Microsoft Accounts
However, the first problem occurred on power-up.  It insisted that she needed to open her Microsoft account. A Skype account was acceptable.  So she put in her Skype name and it wanted to know the email address associated with this. So she put in her usual one.  Immediately it said that there was already an account using that email address and she must use another one. In fact it wanted her to create a new Outlook email account, but that would just give even more emails to monitor.  So she put in her alternative email address.  Unfortunately, perhaps due to unfamiliarity with the keyboard, she mistakenly hit the return key whilst entering the address, so the email address was entered with a part of it missing.

She wasn’t asked to re-enter it as a double-check: instead told her it had sent a confirmatory code to this non-existent email address, and would she please enter this code to prove ownership. Obviously it was impossible to complete this process.   But when we tried to go back, it simply told us that as we’d ‘changed the alias’, we would have to wait to change it again.  A Google search showed that we wouldn’t be waiting ten minutes or even 10 days, but 30 days!  What a dumb-ass system.  Luckily, I was able to get the account that uses her main email address, working, but it took hours and a lot of hassle.  By this time, she no longer trusted the shiny new computer. Aaargh!!! The opposite of what I, and I assume Microsoft, wanted.

Setting it up

The new laptop came with Windows 10 Home 64-bit, which I didn’t think about until I discovered this doesn’t have Remote Desktop, which I use a lot. Luckily this doesn’t matter much for my partner, but I’d miss it if I wanted to sneakily connect to the Raspberry Pi.   I’ve loaded it with MS Office and Adobe LightRoom.  The latter I’ve loaded from the DVD-ROM that it came on – hence the benefit of the DVD Drive.

Copying files

I copied the documents and photos across from the old computer.  Here, I came across a definite improvement in the latest version of Windows 10.  Now that computers tend to rely on wireless connections, you need a way to share connections easily and safely between your computers. Previously, there was the Homegroup system, which was a sort of cut-down ‘domain’ system.  If you set one up, you have to save the long password to connect each device.  But I got into a problem because I set up one Homegroup between two computers and then another Homegroup between a new computer and an existing one, partly because I couldn’t find the password for the existing Homegroup.  This resulted in conflicts between the two and I could not find any way of unwinding the situation.

I was stumped until I found that you can connect computers using the UNC (universal naming convention).  Basically, you can type the path of the computer you want to connect to.  For example, to connect to Albert’s account on computer Basher, in File Explorer you type:


Obviously you need Albert’s login before you can connect to his account (although you may be able to connect with another login if sharing is enabled).  Sharing has to be set up on the target computer by someone with admin privileges.

This is really neat and very powerful, although sometimes the security system is very obstructive in allowing sharing, and you need to persevere to make it work.

Setting up Adobe Lightroom

Lightroom is a really good integrated cataloguing and photo editing system.  Photo editing is somewhat limited – mainly to adjusting individual photographs, rather than the full creation of photo-based artwork that Photoshop can do.  The catalogue is brilliant, but it does have some silly limitations, at least in version 4, which I have.  They tell you that you should move photos to the new location using Lightroom’s built-in move facility.  Lightroom’s built-in help is a nightmare.  In fact the help isn’t built-in, you go to a website and will find that the help is for a whole host of Adobe Photo products and isolating the help for your problem is a matter of perseverance.  For example, it’s no good looking for ‘moving files’.  The help is under ‘Manage catalogs and files’.  After pages of irrelevant help, you find that ‘You cannot copy folders in Lightroom Classic, you select the folders in the Library Module and drag to another folder.’  I don’t think I would dare to risk this for anything other than the smallest job, and certainly not for the 30,000 photos spread across several disks.

Of course, you can copy the files in Windows, which I did.  But then the Lightroom Catalog has to be adjusted to find them again.  Amazingly this is quite easy to do, except that it tells you there is a conflict in the metadata!   Basically, the Catalog has all the photo keywords like Bill, swimming, Blackpool, but the photo file contains all the other stuff like the camera, exposure, date, and GPS.  For some reason, Lightroom doesn’t put these back together – you can have either the camera stuff or the keyword tags.  This is just obtuse.  It’s not surprising that they advise you to keep the photos on an external drive and to carry it from one computer to the next.

Well, I shall now hand over to my partner and keep my fingers tightly crossed!


Printer drivers
After a good six months, the new machine is a great success.  There was a slight issue with the printer (an HP multi-function device).  Windows helpfully instals a generic printer driver which worked quite well, but it seemed to have trouble with some fonts and did not provide access to the scanner.  Even though I’ve had the printer for 10 years, I was still able to download a full driver from the HP website.  After installing that, we now have full access to all the printer’s functions. Excellent!

Adobe Lightroom
Whilst my earlier criticisms of the shortcomings of Lightroom still remain, we have been using one really nice feature.  We had many photographs taken in South Africa on a Panasonic Lumix camera.  Unfortunately, many of them were very dull.  Perhaps this is due to a camera setting, but this camera perhaps offers too many functions, some rather obscure.  The menu system for accessing them is downright cumbersome – I would say that everyone just wants to get a perfect picture as reliably as possible. I appreciate that some lighting conditions are demanding, but bright light should be nearly ideal for ordinary snaps.  I have a feeling that the brightness was confusing the metering system.

Anyway, once you have found the right adjustment (in our case, all the photos were under-exposed, lacking in saturation and contrast), you can save it as a ‘preset’ or just copy and paste to another photo. The beauty of the adjustment system is that the adjustment is not applied permanently to the photo, which remains unchanged, so you don’t lose quality by modifying the adjustments later.  It is simply a record of the settings, which are applied when the photo is displayed or exported.  If you want the adjustment to be permanent, you have to export the photo to another file.  This could be slightly inconvenient, but when you’re creating a slide-show, you need to export the photos anyway.


Raspberry Pi Enclosures

A change of subject today.  Raspberry Pi enclosures.  There are an awful lot of them about.  This is not a scientific review but describes my experience with a few that I have tried out.

Raspberry Pi B
Raspberry Pi B

The first one was the Pimoroni, made of  multi-layered, multi-coloured Perspex sections, held together with long nylon bolts at the four corners.  It was fine and I used it in my Barometer.  The only trouble is that you have to undo the bolts to gain access, which can be inconvenient, but they give you a groovy little ‘spanner’ to assist, and if you connect a ribbon cable, you’ll rarely need to do this.  So it’s great fun.  I fixed it to the Barometer casing by replacing the nylon bolts with brass ones, taking care to insulate the circuit board where the bolts passed through. It has plenty of ventilation.  Perhaps not the most convenient project enclosure and not the cheapest at around £11 +VAT.

Pink and white enclosure
Pink and white enclosure

The second one was the ‘Official Raspberry Pi’ raspberry pink and white groovy-shaped box. Around £5.50 +VAT from RS Components. It is easy to clip and unclip the lid, the sides and the inner cover, and to get access to the GPIO pins. It has soft plastic pads on the base, but with the Pi being so small and light, it won’t stay on your desk if there is any tension on any of the connecting leads.  There are no fixing holes. You’d need to take the lid off if ventilation was an issue.  A very pretty box but very much at the mercy of your connecting leads.

Raspberry box with covers removed
Raspberry box with covers removed
Clear plastic box
Clear plastic box

The third one was the DesignSpark  clear transparent case (available in other colours) also around £5.50+VAT from RS.  This has ventilation holes in the base and slot all round the sides of the case.  However, the lid is only held on by the friction fit of four small lugs.  Once you have taken the lid off a few times, you will need sticky tape or some other way to keep it on.  It is very easy to assemble and has fixing holes in the base. Also, you can easily see the indicator LEDs and the GPIO connections.  This has become my favourite for project work.

Clear box with Pi board fitted
Clear box with Pi board fitted

The fourth is an entirely different proposition. It is the DesignSpark ‘Quattro’ case which holds the Pi and a thin 2.5-inch HDD (or SDD) in a very presentable square black box. (Other colours are available.) This is intended for use as a media server and is a very neat solution, for only £8.99 +VAT from RS Components, which is inexpensive when you look at the cost of ordinary project boxes.

Prior to this, I’d intended to put the Pi in a sandwich box along with a USB hard disk, but I was put off by the work involved in making access holes for the HDMI and power leads and fixing everything firmly.  My other half complained that it looked too complicated and untidy to have on the TV stand, and I’d gone back to saving home videos onto USB flash drives.  They supply it with a ‘VESA’ mount which would allow you to fix it onto the back of a monitor to provide a nice all-in-one display unit.

DesignSpark Quattro Case
DesignSpark Quattro Case

This box makes it all much neater. You put the Pi circuit board in first, and then a bare-bones 2.5 inch HDD. The base then clips on firmly.  You can access the Pi’s GPIO pins and the camera and display connectors from above.  There are no apertures in the box specifically for these connectors, but they supply spacers which will create a slot between the lid and the sides if you need access or to add a circuit board or HAT.  Also, there is a small round aperture at the ‘front’ of the box and a slot behind it to hold the Pi’s camera, so you could use this as a webcam or even a ‘hidden’ camera.  However, next to the camera aperture there are two light guides for the Pi’s activity LEDs, so the Pi’s presence may not be secret.

The Quattro case with Pi board and Seagate Hard disk
The Quattro case with Pi board and Seagate Hard disk

The camera aperture is in a slot-in cover which can be removed to reach the SD card. The whole unit can be secured by screws from underneath (not supplied) to deter prying fingers or accidental disintegration.

Seagate Barracuda 1 TB disk
Seagate Barracuda 1 TB disk with USB connecting cable

I bought a Seagate Barracuda 1 TB 2.5 inch SATA HDD for storing the media. This disk requires a power supply of 1A at 5V which is supplied over the USB connector. I could have gone for a larger capacity, but this will be fine for my purposes.

The box does not have any means of connecting the HDD to the Pi.  I have bought a StarTech USB3S2AT3CB USB to SATA connecting cable for this.  Although this cable is very short, you have to coil it rather annoyingly round the outside of the box.

Logitech keyboard
Logitech keyboard

Of course, a media server needs some sort of user interface.  I bought a Logitec K400+ TV keyboard for this purpose.  It uses ordinary wireless communication, not Bluetooth.  I’ve had trouble with Bluetooth keyboards.  They seem to go to sleep after a period of inactivity, and when you press a key to pause the film, etc, there is no response.  If and when the keyboard and Pi start talking again, you have tapped so many keys so many times that either the program has crashed or done something equally annoying. I’ve also had trouble with pairing Bluetooth devices – some won’t pair at all. The wireless keyboard doesn’t seem to suffer from this, and it includes a trackpad for scrolling and selecting.

Installing the HDD
The ‘barebones’ Seagate HDD [type ST1000LM048] is not formatted when you get it and the Pi just did not find it. Rather than struggle with sorting it out on the Pi,  I plugged it into a USB3 port on my PC which simply showed a device called ASMT 2115 SCSI Disk Device.  The Seagate disk manager software refused to do anything because it could not detect a Seagate disk.

So I went to the Windows Run command and started the disk manager using the command run diskmgmt.msc.  This showed the Seagate drive but said it was uninitialized. Being careful not to select the wrong drive by mistake, I selected that drive and clicked initialize.  I assigned an arbitrary drive letter and gave it a volume name, SeagPiMedia.  Then I formatted it with NTFS.  This file system is readable on both the PC and the Pi, which means I can put files onto the disk using either machine.

After putting some video files on it, I plugged it back into the Pi.  It was then visible in /media/pi/SeagPiMedia. Brilliant!  I put some video files on it and they play beautifully using OMXPlayer and Kodi.  The keyboard works very well too.  Maybe we can view our my old videos again.

Repairing LED Fairy Lights

LEDs with rusted lead
LEDs with rusted lead

LEDs are supposed to be long-lasting, so why have mine lasted only two seasons?  The answer turned out to be RUST!

Before I say any more, I must issue the customary warning not to tamper with anything electrical unless you are familiar with the risks involved and take care. You could get an electric shock or burn your house down.

I had a string of 240 ‘multi-coloured’ LEDs – in fact, four single coloured lamps alternately red, blue, green and amber along the string. In two separate parts of the string, the red and green lamps did not light.

It seemed fairly clear that the controller was working, as in some parts of the string all the lights came on.  The wiring looked fiendishly complex, with five wires running along parts of it, although only three wires came from the ‘multi-function’ controller.  I speculated as to how they controlled four colours with only three wires: I could not see why so many wires apparently went into one lamp in some places, but the covering of shrink-sleeving around the lamp connections made it impossible to work out. In particular I was puzzled as to why red and green had failed in two places, but blue and amber were OK.

After some hesitation, I decided they would have to submit to the knife.  Out came Stanley and I slit along the length of the sleeving on the first dead lamp and to my surprise, at the base of the lamp was a good coating of rust.

I had not expected this – in the old days, electrical devices used copper and brass for all the conductive parts, but device leads, such as in resistors, transistors and LEDs are now made from plated iron or steel.  Since electrical circuits need to be kept dry, this may be acceptable in general, but these were clearly marked for ‘Indoor and Outdoor use’, with a rating of IP44 ‘Splashproof’. If that means they can’t be immersed, I’m not bothered.  I’d put them over a shrub in the garden and no doubt they were rained on quite a bit.

The rust only seemed to be superficial on the first lamp, so I slit the sleeving off another dead one – there was a lot of rust and one of the wires broke off at the bottom of the lamp — or was it already broken? Not only was the lead rusted, but the metal electrode within the lamp was red with rust.  In the end I decided that I’d have to cut off the insulation on all the dead lamps. On several, one of the wires broke off – and I soon realised that in each case this was the positive wire.  I had tried to measure the voltages, but on the DC setting I got some silly low, unsteady value.  On AC I got about 5 volts. Interesting!  I was aware that on ‘multi-function’ lights, the brightness is controlled by switching the lamps rapidly on and off – on simple controllers, this is done by ‘phase control’ – the lamp is only lit for part of the mains sine-wave cycle.  Clearly, my inexpensive voltmeter was not able to cope with the fluctuating cycle on the DC setting. Probably the voltage was not accurate on the AC setting either, because (I imagine) it is designed to measure the RMS value of a sine wave, probably at mains frequency. Of course, on AC, you can’t measure the polarity, so how did I guess the polarity?  On common LED lamps, the positive lead is made longer than the negative lead.

Connections in LED
Connections in LED

Simple! Not!!! The leads had been trimmed before fitting and in some cases they’d already broken off. The saving grace was that on most LEDs, the two connections inside the lamp are completely different – one is large and has a cup or bowl right in the centre of the lamp moulding.  This is the negative or ‘cathode’.  The positive is a smaller and thinner electrode.  If you have good eyesight, you can see that a very fine wire runs from the end of this electrode and loops over to touch the centre of the cup on the cathode, which contains the light-emitting semiconductor material.

Puzzling out the wiring, I soon realised that the red and green lamps are connected with 12 in series, and the blue and amber lamps likewise with 12 in series.  So the string of 240 lamps is made up of 10 sections, each section containing 12 lamps red and green and 12 blue and amber lamps.  So if one green lamp fails, for example, all 12 red and green lamps in the section will go out.  The diagram below shows the schematic of two of the ten sections.  There is a 100 ohm resistor in each chain to limit the current. Given that each LED requires a forward voltage of about 2.1 v (the exact value depends on the semiconductor material being used) and that the power supply is nominally  30 v, this gives a total forward voltage of 25.2 v, and thus 4.8 v across the resistor, giving a current flow of 48 mA. In fact, LEDs are normally limited to a current of 10 to 20 mA, so it is possible that the output voltage of the controller is slightly less than 30 v.

Wiring of LED string
Wiring of LED string

I went to Maplin and bought a ‘lucky bag’ of mixed LEDs.  I just unsoldered the broken lamps and soldered in new ones of the same colour, taking care that I put them with the ‘cup’ or cathode facing towards the same end of the string as the good lamps.  Making sure that there were no short-circuits, I switched on.

Hey Presto! Nothing happened. No loud bang, but the new section was still dead. What a waste of time! But, out with the voltmeter. I accidentally short-circuited across the leads to one of the new lamps. Abracadabra!! the other lamps all came on.  For some reason, the lamp at one end of the circuit should actually be connected with the cathode facing the other way. A quick dab with the soldering iron and all was working.

The final job was to replace all the heat-shrink sleeving. Well I haven’t got any, and I haven’t got a heat gun either. So I used cling film. It’s not pretty – it’s not waterproof. But it will be fine around the picture rail or on an inside tree.

So why have the leads rusted like that?  Obviously, the heat-shrink sleeving isn’t water-tight and the warming and cooling of the lamp will tend to draw moisture in. There must then be some sort of electrolytic action – in each case the anode (positive) connection had rusted through.  Rust (iron oxide) does not conduct electricity, but water contains dissolved salts (carbonates and chlorides) that do. The flow of current, albeit tiny, speeds up the corrosion. Iron expands as it rusts, and this can cause cracks within the plastic casing of the LED and allow moisture to get inside, causing further corrosion. The makers could stop this by using a flexible sealant, but it’s not worth it for lights intended to sell cheaply and be replaced when they fail.  I can’t explain why the green ones failed most: do they heat up more? Was the plating on them thinner?

If I’d costed my time, the repair wasn’t cost-effective either, but I’ve learned a lot.


PS – I should say something about the ‘Positive’ and ‘Negative’ connections on a diode – be it an LED or rectifier.  LEDs light up when a ‘forward current’ is passed through them. This means that the current flows from the positive pole to the negative pole. For a diode, current goes into the device at the Anode and out at the Cathode. [This is a convention decided by early physicists  long before they discovered that electrons flow in the opposite direction: and it still remains true.]  If you make the cathode positive and the anode negative, no current will flow, unless the voltage is so high that the device breaks down. However, when a diode is connected as a rectifier, the current comes out of the cathode.  This makes it look to be positive, but it is still at a lower voltage than the anode, so as far as the diode is concerned, current is still flowing in the correct direction.  You can see this in the Bridge Rectifier circuit I have drawn below.  The positive terminal of the rectifier is actually the cathode of the diode.  I think this is why the cathode of a silicon (rectifier) diode is marked with a line around it. Anode actually means ‘leading to’ and cathode means ‘leading from’.

Bridge Rectifier
Bridge Rectifier

A further question is ‘Why is this called a Bridge Rectifier’?  It’s because its shape is the same as in a ‘Wheatstone Bridge’, although that was used for measuring resistance.


As a youngster, I had a point and shoot Kodak camera that used 127 film and you got eight black-and white photos out of a reel of film. It was quite expensive to get them printed and they were of variable quality as there was no focus or exposure control.  The rule was to take them in bright sunlight with the subject facing the sun, so people often had their eyes screwed up against the light. When I became a teenager, I had saved enough money to buy an Ilford 35 mm camera which had shutter and aperture controls, and a little light meter so that I could get more accurate exposure.  This was essential for taking colour slide film – Kodachrome II which had a speed of 25 ASA (now called ISO).  You had to send the film away to Hemel Hempstead for processing.

This was a very slow film but had fine grain and produced excellent colour.  However, you still needed bright light otherwise a slow shutter speed would mean blurring.  I did some night photography, but a tripod was essential to avoid camera shake.  Of course, you couldn’t change the focal length, but this was good discipline as you had to find the right viewpoint to get a good shot.  Colour prints were far too expensive for me as a teenager – the film itself was costly and then you had to pay for the processing and the prints.

When I got a job, I bought myself a Pentax Spotmatic F SLR.  This had a fabulous 55 mm standard lens with an f1.8 aperture, which was great for colour slides as it had accurate TTL (through the lens) metering and it was easy to set the exposure.  Also, colour prints were getting much cheaper and over time, I moved to using print film.  I became adept at making my own colour prints, too.

I did buy myself a 135 mm telephoto lens but I never used it very much as I preferred landscape photography.  Both lenses were superbly sharp.  But I realised that zoom lenses and automatic exposure were becoming the norm – these allowed quicker photography in a wider range of situations, especially as films were becoming faster with 125 and 250 ASA films giving good, sharp images.  This meant that the smaller apertures available with a zoom lens was not a problem, and print films are in any case more tolerant of inaccurate exposure.  So I bought a Canon EOS camera with a standard zoom kit lens.  I was sadly disappointed with this camera.  The lens sharpness and aperture was not a patch on the Pentax.  I started to read about digital cameras and one day I took in film into the local photographic shop, and saw some small digital cameras in the window.  I asked for a demo and came out with a small Nikon Coolpix, which was expensive – about £300.  I thought it would just be a bit of a toy, but I was gob-smacked at the quality of the images and when I went back to collect my photos, I said the owner of the shop that I reckoned it was the end of ‘chemical’ photography. “Oh, no, not at all”, he said, “It will see me out.”  Whilst I’m sure it was not what he meant, the shop had closed within a few years: it had relied too much on the flow of customers getting their films processed.

Now, of course, the quality of digital photographs far exceeds what silver nitrate films could achieve – both in terms of definition and in terms of effective ‘film speed’.  I see that 25,000 ISO (formerly ASA) sensors can take photographs with a definition and colour accuracy that was inconceivable a decade ago, but needing only one-thousandth of the amount of light.

Sadly, this doesn’t mean that it is any easier to take a good photograph – namely one that perfectly captures a mood, expression, the essence of a place or event.

But it is easier to have a go.

Using a video editor

I’ve been rather busy – bell-ringing, going on holiday, doing work – so I have not had time to write my blog – sorry!

I’ve installed Photoshop and Premiere Elements 15, and I have made a video of how to repair a Bosch TMX 25 Garden Shredder. More of that below.

Firstly the software. What has changed between Version 8 and Version 15?  A great deal – some for the better, and some for the worse.  Looking at Premiere (video editing):

Better –

  • it now expects people to be using HD 1080  or 720 pixels
  • it is simple to render to High Definition
  • it makes it easy to upload to YouTube or FaceBook

Worse –

  • The interface has been ‘simplified’;
  • Everything is chunkier;
  • Features have been hidden or even entirely removed.

This even applies in the ‘Expert’ mode, and it will be frustrating to those of us who know and understand the old system.  There are now so many different parts to the ‘Adobe Creative Cloud’ that it is really difficult to know which one to use at times – and they don’t always integrate properly.  Despite the chunkiness of the user interface, Adobe have decided to use mysterious icons for the various parts of the system.  I find it really difficult to tell the icons apart.

Worst of all, as I’ve said before, the Help is not dedicated to the piece of software that you are using. I was trying to make a slide show: you can use LightRoom, Photoshop or Premiere for this. They are entirely different processes, though. I wanted to find out how to control the transitions between slides, so in Photoshop Elements, I clicked on Help and the web-based help opened to give guidance on practically every item of Adobe software where transitions apply. Not helpful: eventually I found that in Photoshop Elements 15 they have removed any possibility of controlling transitions!

Furthermore, I had some problems installing the software, with mysterious error messages.  In the end, I had to uninstall and re-install. I think it is working – time will tell.

The Bosch Shredder

I bought this shredder a few years ago to dispose of some Leylandii and other garden pruning – a huge stack of them. It worked brilliantly – I was able to take all the shreddings to our local recycling centre, which didn’t charge at the time (they do now).  It was an expensive machine – over £400 at the time – but it cut up branches up to about 1 1/2 inches diameter with no problem.

Then the council rented us garden waste wheelie bins for about £35 a year, and again the shredder enabled me to fill it with prunings that I would never have got in just by cutting them up.

I had some more stuff recently, and I was puzzled that the branches were not pulling through properly and the shredder was just jamming. It was extremely annoying. My better half then noticed that the cutter was turning backwards – it did not matter whether you pressed the forwards button or the backwards button it still went backwards.

Since it seemed to be working perfectly otherwise, I surmised an electrical fault – I took the cover off the control panel and saw that there was a complex circuit board.  A web search showed that this ‘backwards only’ problem was a known fault with a certain batch of these machines.  A further search showed that it was possible to buy a new circuit board. Since there was no visible sign of other damage, I decided to take the plunge and buy a new circuit board.

My video shows that it was easy to fit (apart from being a bit fiddly) and cured the problem.

More to follow – but need to get some bell-ringing in just now!

Video Editing Software

I have been asked what video editing software I use and can recommend.

Years ago I bought Adobe Premiere Elements and I have used this a lot.  More recently, I bought Sony Vegas Movie Studio HD Platinum.

They are both good systems and both have their strong and weak points.  Although they are aimed at amateurs, this does not mean that they are totally intuitive – far from it.  You need to get your head around many new concepts if you haven’t done any video editing before.  Both systems are very similar in concept – the main differences are in the implementation – the tools provided and their ease of use.

Premiere Elements (Prel) is aimed more at the person who wants to create a movie quickly and with the least fuss.  It is also less demanding on screen ‘real estate’ – i.e. it can be used on relatively small screens.  Vegas is harder to use on small screens: this is partly due to the fact that it has more windows, but also because the ‘handles’ used to access the trimming, fade and effects functions are smaller, perhaps because there are more of them.

If you intend to invest in Vegas, you will probably also be investing in a large monitor, and perhaps two monitors.   I presume Prel handle ‘surround sound’ but so far I have only used this with Vegas. A big downside is that you end up with five extra audio tracks to manage.  My movies tend to be of the documentary type, that don’t really benefit from the extra fuss and bother. You definitely need the extra screen ‘real estate’ if you’re into this.

There are three main parts to a video editor – the media (the video and audio clips that you are going to make into a movie), the timeline (the sequence of clips in your movie) and the monitor window where you review your work.  Both systems allow you to add media to the timeline in the sequence that you desire.  You can ‘trim’ the ends of each clip to shorten them and remove wobbly bits.  You can cut a clip at any point and then trim out bits from the middle of the clip.  This is easy to do in both systems.

I like the fact that when you start to preview your movie, Prel keeps the position marker in the middle of the screen and the time-line scrolls past it.  This means that you always see where you are.  The disadvantage is that it doesn’t fully update the thumbnails on the time line until you pause the replay.  Vegas moves the timeline cursor, which means that it drifts out of sight.  This means you can’t always see where your track overlays begin and end whilst watching a preview.   Worse than that, if you accidentally double-click on a clip in the media bin, it automatically adds it to the time line at the position of the cursor.  If this is off the screen, you don’t see the mayhem you are creating!!

In addition to the raw clips from your camcorder, you will need to add other things like titles and possibly ‘voice-over’.  Avoid the temptation to do this too soon, because keeping them in the right place on the time-line can be a nightmare.  This is a problem that still bugs me.  Prel seems better at keeping titles in the right place even when you do a lot of editing.  I have had a lot of trouble with Vegas on this issue.  Admittedly, my Vegas movies have had surround sound, two video overlay tracks, narration and music, so it is a lot to keep in sync.  Sometimes, you want to reposition narration relative to the video, but I find it almost impossible to see whether the ‘ripple edit’ button is active or not, or to be sure which tracks it is going to affect.

Prel, perhaps given its origins from graphics experts, is actually really good at producing brilliant-looking but straightforward titles, where as Vegas permits titles of the utmost cleverness, but which would take hours or days to get right.  Only professionals or those with time on their hands would ever use these features.

An issue that seriously bugs me is that of context-sensitive help.  You will not be able to use either of these systems without extensive use of help, because many features can only be accessed in ways that seem quite bizarre to me.   Vegas has proper context sensitive help that gives accurate and non-patronising instructions.  Prel always opens help from the web showing for example ‘essential and fun things to do today’.  So you have to start a search for what you want, such as editing a title.  But of course, there are umpteen versions of Prel and unless you have the very latest version, you may find that the instructions are almost, but not quite, accurate.  This bugs me so much that it is a real deterrent to using Prel.  And whilst I said that Prel is modest with screen space, the help (which it would be nice to keep open in a corner of the screen) is beautifully arranged to take up the most space possible.

What is my final verdict?   Unless you really intend to produce dramatic videos, I think that Premiere Elements  has everything you are likely to need.  It is a lot cheaper than Vegas and less demanding on screen space.  If I do decide to update, I will be updating Prel rather than Vegas, I think.

A GUI for omxplayer

The Pi is a wonderful device for those who enjoy a bit of tinkering. TBH, it won’t do very much until you’ve tinkered!

So, I’ve shown that I can play my AVCHD videos on the Pi by using omxplayer, which is pre-installed (but not obviously).  Although omxplayer is very versatile, it relies on you typing all sorts of obscure instructions on the command line. If you’re adept at scripting you can automate a lot of this, but if you’re running the desktop – aka a Graphical User Interface or GUI – then that’s what you want for omxplayer too.  I have found one called tboplayer which seems fine.  I have only one issue so far – it leaves a space at the bottom of the screen for a progress bar, and so the picture doesn’t stretch to the sides either. Presumably there is an option to avoid this.

The other issue that is puzzling me is whether I need to install an mpeg2 codec.  According to the forums, the codec enables hardware decoding by the gpu, rather than using software decoding. I know that AVCHD requires more decoding power than MPEG4, but the picture is smooth and without stuttering as it is. [My Sony Bravia TV has AVCHD decoding built in, but I have been getting some stuttering when using a file stream from my NAS.  However, this is more likely down to the network speed.  But it meant that the only way I could enjoy my home videos was to put them onto Blu-ray disk.]

I have also read that the hardware decoding gives better picture quality (presumably because software decoding takes some shortcuts to reduce demand on the processor).

Since the codec costs less than £3 from Raspberry, I think I can justify the cost.  It’s just a pity that it isn’t easier to find a reliable source of information about this. It seems that the Pi Foundation is a little bit diffident about the subject as their original concept was for the cheapest possible worthwhile educational tool, and they didn’t intend it to be used as a media player, as in its original form it didn’t have the power to do it well.

[Talking of which, I was searching for information about codecs, when my browser came up with a red screen and dire warning that my PC was infected with a Trojan.  I couldn’t close the browser and had to use Task Manager to close it. Luckily my anti-malware system kicked in and a scan seems to show no ill-effects.  Sites offering ‘free’, i.e. illicit drivers, codecs, etc often have a malware payload.]

So, I think there is a bit more tinkering to do, but it looks as though I will be able to really enjoy my home videos again.

PS – I have now bought the licence codes and enabled the MPG2 and VC1 codecs. VC1 is something to do with Windows Media Player files.  You install the codes in a file called config.txt in the boot directory. Anyway, it has now enabled a video that I couldn’t play before, so it was worth the price of a pint. [I think that people who get upset about paying a few shillings for things like codecs are misguided.  These are incredibly complex both conceptually and in the implementation. Very few people have either the mathematical or coding ability to understand them and most would be old men before they succeeded in writing one for themselves.]

Play a video with omxplayer

The Pi is such an amazing but frustrating device.  It actually comes with a fully-featured Video Player called omxplayer built in, but for some reason they seem to hide this fact. No doubt there are reasons, such as whether it is sufficiently reliable and easy to use.  But also, it seems that only the Pi 3 really has the oomph to play high definition video, as it has a dedicated video chip to do the decoding.

It has taken me several days of ploughing through the forums to appreciate that this viewer exists and to get it working. When I say that the viewer is fully-featured, I mean that it seems to be able to play a wide range of formats, but so far I only have a ‘command-line’ version. This means that you have to start it by typing instructions at the $ prompt, which can be slow and annoying if you’re as bad at typing as I am.

But the other thing is that in my release of Raspbian at least, it doesn’t run straight out of the box, at least not for mpeg4  HD videos. This is because by default there isn’t enough memory dedicated to the video chip, known as the gpu (graphical processing unit). To correct this, you have to edit the file at /boot/config.txt and at the end of it, add the line
Note that you need superuser status to edit confix.txt, so from the $ command line, use
sudo nano config.txt
to open the file in the nano editor.

If you’re not familiar with sudo nano, search this blog to find my earlier post about it. Don’t try to be ‘pretty’ by putting spaces around the gpu_mem=128 as the config interpreter won’t understand it and the extra memory won’t be allocated.

I will write some more about omxplayer when I’ve done a bit more work on it.   However, I can say that it played my HD holiday video of East Africa with greater clarity than I’ve ever seen before. As I said in my previous post, these were recorded using AVCHD encoding on a Panasonic camcorder, and hitherto I have very frustrated that the edited picture quality was never a match for viewing directly from the camera onto the TV.  I’m beginning to realise that this was a defect somewhere in the playback system.