Tutorial: How to improve your Wi-Fi signal

There are loads of ways to get a faster wireless network connection at home - some of which are more practical than others.

You can hire some heavy machinery and knock down a few walls in your house so the Wi-Fi signal can travel through more efficiently. You can chuck out your current network hardware and buy a new set with the latest specification.

Or you could go down the easier, less destructive, and perhaps most importantly, free route of making sure your network is operating on the right channel and tweaking its settings for maximum speed. It's much like tuning a radio to a different station.

There's a simple reason why you might need to change your router's network channel. When there are many other wireless networks in your local area (which is likely if you live in a city), wireless signals can clash, causing interference that makes network traffic slow down.

There are several possible channels that your wireless network can operate on. We're going to show you how to look at the traffic in your area and move your network to the least clogged part of the spectrum, ensuring you get the best results.

1. Download time

To analyse your local network traffic in greater depth, we're going to use a tool called inSSIDer. It's a full network analyser capable of some incredibly complex things, but we're really only going to skim the surface of its abilities. Download and install the program from here - just click 'Next' repeatedly to get it installed.

2. Scan for networks

Run inSSIDer - you'll find it inside a folder marked 'Metageek' in your Start menu. Click on the tab marked '2.4GHz channels', then look at the top of the screen for a button labelled 'Start'. This sets inSSIDer hunting around your local area for networks. It'll probably find many more than Windows does. Click 'Stop' when you're done.

3. Find a channel

Look at the graph - this is a map of where the networks in your area fall along the 11 main wireless channels. Their height represents their signal strength from your current location. It's down to you to interpret your graph, since it won't be the same as mine. Find an area with some empty space, or a quiet channel, and note its number down.

4. On the router

The channel you picked will be your network's new home. If it's nice and clear, you should get a decent speed boost. To change the channel on your router, you need to log in to its admin interface, which is different for every model. I'll show you the steps we took for our Asus WL700ge - you may need to search the internet for specifics.

5. Log in

I'll start by firing up a web browser and going to the local IP address of my wireless router - in this case 192.168.1.1. This brings up the login screen, where I need to enter my credentials. If you don't know yours, it's likely they haven't been changed from their defaults, so dig out the manual or search online and you should find them.

6. Set the channel

From here I need to access the advanced settings screen, which gives me more options. It's easy to change the channel on this particular router - there's a drop-down box in the middle of the screen that lets me do it. While I'm poking around, I can also look for a number of other settings that will keep my router speedy.

7. More tweaks

I'm given the option of setting a wireless mode - in this case turning off the older 802.11b service. If you still have devices that use it, you'll want to leave it switched on, but since I only have 802.11g devices in my house, I can safely switch it off and claw back a tiny speed boost. Then it's time to head to the advanced wireless page.

8. Radio settings

Here I can fiddle with all sorts of things, but I'll stick to the bits I know will help my wireless speed. Turning the radio power up should mean I get better signal at a distance. The 'afterburner' mode is only useful if you have wireless cards or dongles in your PCs that support it, so I'll leave it off. Frame burst, lower down the page, is a must.

9. Check the changes

After you've made the changes, you'll need to apply them and save your settings. Your router will probably reboot. Once everything is back online, run inSSIDer again to check the results of your changes and ensure that your wireless connection has moved to its new channel. Try a download - you should see the benefits immediately.

10. Speed for free

So you've checked out the wireless channels in your area, found the ideal one for your network and hopefully, depending on your router, switched its channel to an empty space. If it seems to have made things worse, there may be some other interference in the new channel, like a cordless phone, so try a few until you find the best one.

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By: Dilusha On 9:48 PM

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Tutorial: Power retro gaming with a Raspberry Pi

There are many fine national institutions this sceptred isle has to offer: fish and chips, the perfect pint and Great Yarmouth Pleasure Beach to name but a few.

There is one institution, however, that stands proud, shoulder to shoulder with the iconic monuments that make Britain great. One that has bred a generation of imaginative free thinkers. One that symbolises everything that was good back in 'the day'. That one is none other than the mighty 8-bit home computing revolution.

These revolutionary creations were the heavyweight champions of 80s gaming, and some of the most cherished items of computing memorabilia to grace the pages of eBay. To relive those bygone days often requires us to install any number of emulators onto our hulking behemoth PCs, which takes away some of the spirit that embodies the golden age of the home computer.

There's another option, of course; we could purchase one of our beloved machines from eBay and hook it up to the old 52-inch plasma TV. However, these computers are getting a bit long in the tooth, and unless they've been cherished and looked after there's the possibility they could go zap and pop once plugged in to the wall.

There is an alternative, though - one that combines the modern with the not-so-modern.

The Raspberry Pi - arguably one of the best innovations since the home computer, and one that is heralding a new golden era of computing.

This credit-card-sized computer is seeing its fair share of imaginative doings from the public; being sent to the edges of space, turned into a 40s wireless set, home automation controllers and many other projects that have gone to prove just how versatile and elastic the users, and the RPI, can be.

Therefore, we're going to take a leaf from their books, and see what we can do with a few items from eBay, a Raspberry Pi, sticky-backed plastic and help from the growing population of RPi owners, in order to help us re-create a classic 80s retro home computer.

The legal bit The legality of emulation is something of a grey area at the best of times, but in essence: if you own the console, and game, then you are allowed to obtain a copy of the corresponding roms to emulate them. At least that's what we think. If you're not sure, it's always best to look it up, just in case.

Our first port of call is that lovable rubber-keyboarded gem, popularly known as the Speccy. Indeed, the ZX Spectrum 48k was a powerhouse of innovation back in its day, turning bedroom programmers into commercial software giants overnight, where teenagers could come home from school and tap away until dinner time to create some of the best-loved games in computing history.

Anyway, enough nostalgia as it's bringing a tear to the eye. After a brief browse through the pages of eBay, we found a dead ZX Spectrum that came in at the paltry sum of £2.99 - after all it would be sacrilegious to mutilate a living Speccy. It looked a little worse for wear, but then most of us who can recall playing on one of these don't look overly healthy these days either.

Our first task was to make sure the RPi was up to spec; we'd been playing around with it since its arrival in the post, and as things move fast in the world of Pi we felt it was time to do an upgrade to Wheezy.

The system download can be found on the Raspberry Pi pages, along with full instructions on how to transfer it to an SD card, and get up and running. After that we did the necessary sudo apt-get update/upgrade, and within minutes our RPi was up to date and running like a charm.

Next came the dismantling of the ZX Spectrum, easy enough once the five screws on the bottom of the machine had been removed and the keyboard ribbons detached. The motherboard had a single central screw, which after being removed left only the bare plastic casing. The RPi is considerably smaller than the original Spectrum motherboard, so some careful placement was needed to make sure the RPi was situated conveniently and securely within its new housing.

To that end, we found that the RPi's RCA Video and Audio ports lined up nicely with the Spectrum's original Mic and Ear ports, but the RPi's SD card ran into the side of the plastic casing. A quick snip from the pliers made a slot that would allow us to swap SD cards, even when the case was screwed back together, and extending the homemade slot also gave us access to the power via an HTC charger.

Next, we hooked up the HDMI and Ethernet, and with the help of some ever-faithful black electrician's tape, we secured the RPi to the base of the Spectrum case, and taped the cables to the chassis to stop them from ripping the RPi out of its allotted place should they ever be moved.

Now we had the problem of the keyboard. Although there was a project previous to us trying this out, whereby a chap called Brian rebuilt a ZX Spectrum using a BeagleBoard, and successfully managed to get the keyboard working, our attempts fell somewhat short.

In other words, we failed miserably, making a bit of a mess of the keyboard ribbons and the USB interface we shanghaied from a USB keyboard for just the purpose. Still, never mind, we simply caved in and ran a traditional keyboard and mouse through the Spectrum's large IO port.

Once the case was back on, the ZXRPi didn't look too bad, albeit something that would send Heath Robinson spinning gaily in his grave. However, when hooked up to the TV and stylishly, yet discretely, placed in the TV cabinet, things didn't look too bad.

The only thing left now was to install a decent Spectrum emulator and get hold of some old games. The Spectrum emulator itself was easy enough to install and get running; for this project we're using Fuse Emulator, and to get it working do the following:

Drop in to a terminal and type: sudo apt-get install fuse-emulator-common and press Enter. Type, 'y' to confirm the download and install.

Once Fuse has been installed, and you are returned to the prompt, type: sudo apt-get install spectrum-roms fuse-emulator-utils and press Enter. When, once again, you return to the prompt, type in: sudo amixer cset numid=3 2 and press Enter.

This will allow the sound through HDMI, although it's rather flaky, so replacing the '2' with a '1' will force the sound through the audio port on the RPi.

When you're ready, come out of the terminal, and click the Start LXDE button, and navigate to Games > Fuse Spectrum Emulator (GTK+ Version). Click on this and expand the window by dragging one of the corners.

Next, download a Spectrum game, from somewhere such as World of Spectrum; once it's downloaded, from the Fuse top menu select Media > Tape > Open, then in the Spectrum window type, 'J' for Load, followed by 'Ctrl+PP' for "".

Your game should now load up, with sound coming from the audio port, which can be hooked up to a stereo or headphones. All that's left now is to try to complete Manic Miner, which you failed at nearly 30 years ago.

The thought of having a retro-styled case for our Raspberry Pi appealed to us greatly, despite the lack of hardware hacking to get 100% functionality, so we started to look around for other retro machines that tickled our fancy.

Our attention was drawn to an old friend, the Sega Mega Drive; a discrete, sleek-looking unit, even by today's standard, that like the Spectrum would make an ideal retro case for our RPi.

First, though, we need to prepare the RPi for its new life inside one of the best consoles ever made; and we want it to be able to play not only Sega Mega Drive games, but a plethora of other games from the hardware of the era.

To do this, we installed the excellent RetroPie project from petRockBlog; all you need to do is follow the instructions as they are given here.

In this instance, we decided to compile the most recent sources of programs, scripts and cores by selecting the second option from the main menu, the Source-based (custom) installation method. As is mentioned on the site, though, it takes several hours to compile everything, and the RPi is pretty much maxed out for the entire time, so don't expect it to do any work during the three hours of the installation; but bear with it, it's certainly worth the wait.

Once the installation had finished, the RPi got a well-deserved break in the form of a reboot. After that, it was a simple case of locating a game (we're assuming you're following the copyright guideline, as mentioned in this article) and running it, via a terminal, in this format: retroarch -L /home/pi/RetroPie/emulatorcores/Genesis-Plus- GX/libreto.so /home/pi/RetroPie/roms/megadrive/Sonic.md

In the example above, we had a Sonic the Hedgehog rom, which was located in the roms folder under 'megadrive'. Obviously, you will have to alter the command to represent your machine emulation, and the game you want to launch.

Picking up a dead Mega Drive was easy enough, and it cost less than a few quid to get it to the doorstep; but rather than rip out the insides straightaway, we had another cunning plan: would it be possible to house the Raspberry Pi inside the cartridge of a Sega Mega Drive game?

The Mega Drive we received was a little worse for wear; since its birth in 1992 it has seen its fair share of action, so although it was rough we thought this just added to its retro charm somewhat. Obviously, the game would have to be Sonic, and once we got an old Sonic the Hedgehog cartridge it looked as though it may be possible to squeeze the RPi into its innards.

Indeed, the RPi does fit in to a Mega Drive games cartridge, but it leaves very little room for cable management, even with sections of the cartridge plastic snipped away to accommodate the SD card. So, rather than having a savagely hashed cartridge atop the Mega Drive, with a tangle of cables, we decided to install the RPi within the body of the Mega Drive, and use what items we had lying around to try to keep some functionality from the original console.

We planted the RPi onto the Mega Drive base, with the SD card within easy reach through the side expansion port, which can be sealed with the plastic cover, and ran two USB extension cables from the RPi, and fitted them into the front gamepad controller ports.

The HDMI and Ethernet cables were pushed through the power and TV ports at the rear of the unit, and the power came via the side expansion. After making sure everything was battened down, and that the Raspberry Pi wasn't in any danger of sliding out of the side of the case, we started to feed the necessary cables through the correct holes. We carefully attached the lid of the Mega Drive, making sure the screws didn't catch any of the cables or the RPi itself, slid it into its new home under the TV and fed the now reconditioned MegaPi some power.

Obviously, the power and volume controls at the front of the console didn't work, but they added to the retro appeal of having a 90s console, with a modern spin. Our MegaPi functioned perfectly and we settled in for an evening of Mega Drive classics, via the Genesis emulator in RetroPie.

Our next software project bordered on the perverse, from the point of view of a Linux magazine. We managed to get DOS 6.22 and Windows 3.1 running under QEMU on the RPi.

Rather than building the image directly from within QEMU, we used a pre-built VirtualBox image, which we converted to a raw IMG file by issuing the following command: vboxmanage clonehd "image.vdi" "image.img" --format RAW

Replace image.vdi and image.img with the name of your images, then convert the raw image to a QEMU qcow image by typing in: qemu-img convert -f raw image.img -O qcow2 image.qcow

The result was extraordinary, and oddly satisfying to see Windows 3.1 start up and hear those 'ta-da' chimes. Needless to say, it ran like a pig in treacle, but the RPi hasn't got a whole lot of RAM, and after several minutes of running Microsoft's retro OS the screen froze and QEMU refused to boot the image until we deleted and re-converted it. Perhaps Ebon team coded in some kind of Microsoft failsafe kill switch?

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By: Dilusha On 9:24 PM

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Tutorial: Recover lost photos: how to repair corrupt images

Digital photos are an incredibly convenient way to preserve life's most important memories and moments, and are so easy to use that it's tempting to take them for granted.

And why not? You see a thumbnail, double-click it and the image always appears, so you assume it always will.

But of course life isn't always so straightforward.

It only takes something tiny - a scratch on a CD; a bad sector on your hard drive. And, suddenly, a photo could be trashed: split into chunks; colours displayed incorrectly; bits missing; maybe you can no longer view it at all. Your photo - or photos - have been corrupted.

Don't panic, though - there are several programs around which claim they can repair JPEGs.

They're almost all commercial products, but if you want to fix corrupted photos then you can always pass your images through their trial versions, which will give you an idea of what can be recovered (although repaired images tend to come with a bulky watermark until you buy the full package).

So which tool is best?

To find out, we've tested seven of the most well-known contenders, and the differences are absolutely amazing: some programs really deliver, while others are entirely useless. Keep reading to find out more.

To benchmark our repair tools we needed some corrupted JPEGs. And so we set about creating some, by intentionally damaging four groups of images in very specific ways.

Test 1, 'Zero Signature', was the simplest: we just zeroed the first two bytes in every image. No critical data was lost, so we would expect any capable recovery tool to fix the problem.

Test 2, 'Zero Header', was an extension of the same idea, zeroing the first 32 bytes. This would be a little more difficult to fix, but should still be recoverable.

Test 3, 'Lost intro', saw us delete the first 8KB of every file (that is, the corrupted file started at original file byte 8193). Obviously this missing data can't be recovered, but could our tools make at least something visible?

This is a tough test.

And test 4, 'Lost middle', saw us delete 8KB from the middle of each file (so the data isn't zeroed, it's removed entirely and the file is 8KB shorter). Again, the lost data can't be restored, but would our test programs make the photos more viewable?

It was time to find out.

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By: Dilusha On 8:11 PM

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Tutorial: Turn your Linux PC into a gaming machine

You don't need a cutting edge card for Linux gaming

Linux-based operating systems have long been the alternative OS for us PC users, but there are several reasons why they haven't garnered the mainstream following they perhaps deserve.

Most of the issues stem from the unfamiliar way they work compared with the operating system we've all used a million times before: Windows.

For most of its life it's demanded that its users get elbow deep into command lines - something most of us forgot when Windows 95 happened. It's also had very patchy support for different components, and gaming on a Linux box was generally an exercise in needless frustration.

Things are changing quickly though, and the latest versions of Linux stalwart Ubuntu have been increasingly familiar and functional, and more importantly, easier for the general public to use and get their heads around.

With Windows 8 radically changing the way you interact with your operating system, demanding that you learn these new ways before you can feel comfortable in the new Windows' new surroundings, it's never been a better time to pick up a Linux distribution and learn the ropes on something that's a lot more customisable.

When it comes to gaming though, things are still a little tricky. Gaming through WINE is still rather hit and miss, but the good news is there's a version of steam built specifically for Linux setups that could ensure Linux gaming becomes a viable alternative to the Microsoft-dominated PC scene.

Component compatibility is something the manufacturers will have to become more au fait with though, and we're going to investigate just how well the big players are doing right now.

We've picked some of the most vital parts for penguin-based systems - the processor, graphics card and solid state drives - to see how they fair in the alternative operating system.

We'll see how they get on with the latest manufacturers' drivers and, where we can, with any open source drivers that might be available.

Can you still be a gaming, component-swapping guru running a Linux-based PC? We say hell yes, but you're going to have to be picky with the parts for penguins.

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By: Dilusha On 9:26 PM

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Tutorial: How to save time when editing in iMovie

By Steve Paris from MacFormat Issue 251 November 18th 2012 Master the basics of Apple iMovie

Editing is often the trickiest part of building a home movie - which is rather inconvenient, since this is the one task that takes up the most time when working with video.

As a result, the way you interact with your footage is crucial: if it's too tricky, you'll most likely give up in frustration and move on to the other things you have to do in your day.

Calling editing 'fun' depends on how fascinated you are in the process of picking clips, trimming them and putting them together to tell a story. Even if you feel resentful at having to do any of that, but have to get that movie ready for others to enjoy, you'll find that iMovie does its level best to make the process as organic and intuitive as possible.

In fact, Apple had such confidence in the way editing worked in iMovie that when Final Cut Pro was rewritten, that very concept migrated from a consumer program to a professional one. The advantage here of course is that once you've outgrown iMovie, moving to Final Cut will feel like a natural progression.

But we're getting ahead of ourselves; this tutorial shows how some of the basic editing concepts work in iMovie, and we'll hopefully teach you that editing with precision can indeed be fun.

Start a new project (Command+N) and select an Event from iMovie's Event Library (lower left). Move the cursor over one of the clips to see it appear on the main preview section (upper right). Skim through your footage to find the right piece you need. When you have, click on it.

This automatically selects four seconds of footage which you add to your project by dragging it over. To choose a different amount, click and drag on your clip, or use the handles to fine-tune your selection. Add multiple clips to your project and slowly build your story.

The order of your clips isn't set. To change it, drag a clip and a green bar previews where it will end up. You can also add a clip in the middle of another: drag one from the Event onto an existing one in your project. A menu appears; select Insert. This cuts the existing clip in two.

There's another option called 'Replace'. This replaces the existing clip with the one you're dragging in. It won't match the existing clip's duration, but removes it and adds the new one instead. Think of it as delete and replace; to just delete a clip, select it and hit the key.

With a clip in your project, you may need to make fine adjustments so it fits better within the flow of your story. To do this, move your cursor over the clip and a cog icon appears. Click on it and select 'Clip Trimmer'; the whole Event section is replaced with another tool.

The Clip Trimmer shows all the footage available from the selected clip. You can use the yellow handles to resize your selection as you did when you first chose the clip or you can drag the highlighted portion to select an entirely different part.

If you just want to extend or reduce your clip's duration by a few frames, you don't need the Clip Trimmer at all: hold down Option+Command and move to a clip's edge: it turns orange. With those keys still pressed, you can add or remove up to one second by dragging that edge.

If you're not a fan of keyboard shortcuts, go to iMovie's Preferences (Command+,), select the Browser tab and tick 'Show Fine Tuning controls'. This adds a new button on either side of the clip your cursor's over. Clicking on it enables you to trim that edge without having to press any keys.

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By: Dilusha On 7:22 PM

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