Jeff Atwood

Our Vertigo Business Cards

I've always liked our business cards. They're one of the things that impressed me about Vertigo when I first interviewed here. Cool business cards are always a perk. Here's a quick scan of the current model:

There's a little hole in the middle and a cool spiral design on the back, so you can experience some "Vertigo" yourself by spinning it around.

We've had the same logo since 1997, when the company was founded, so we're probably overdue for a rebranding. And we're getting one February 1st-- we'll be inducing Vertigo a whole different way. I'll post side-by-side scans of the new business cards next to the old ones.

Samsung Blackjack tips and tricks

The business development team at Vertigo recently standardized on the Samsung Blackjack phone.

It's fantastic hardware. The smartphone has finally shrunk to a pocketable form factor after all these years. Ironically, it's the software that needs to improve -- the Windows Mobile 5.0 OS on the phone leaves a lot to be desired. It's not exactly intuitive.

I dug through a massive tips and tricks thread trying to figure out ways to work efficiently in Windows Mobile on the Blackjack. Here's a summary of the best:

• Hard reset the phone by holding down UP and POWER to boot. It will ask to confirm.
• You can adjust the brightness of the screen in Settings under Power (scroll down)
• Pressing and holding the Home button brings up the task manager
• Pressing and holding the jog dial brings up a list of apps
• Pressing the power button brings up the quicklist
• Hold down message key to turn off backlight on screen.
• Fn + B = Toggle Bluetooth
• Press the V key for PAGE DOWN and the T key for PAGE UP.
• Hold down any key while typing to get its "alternate" character. i.e. Hold down the Q for a moment and you'll get the + symbol. This is nice if you don't like hitting Caps/Shift Q to get it.
• if you are reading an email, press the center d-pad "action" button... it will take you to the new contact entry with that persons email address already filled in.
• Apparently the phone doesn't support automatic keylock, you have to hold down the "end call" key for 3-4 seconds and it locks the phone.
• When you have a URL in the address bar hold down the BACK button above the red hang up button and it will delete the entire URL.
• In any of the edit fields (contacts, I.E., and others) if you hold down Undo (top right U-Turn with an arrow) it will delete the contents of the field you are in.
• There is no way to get periodic reminder tones for missed calls or messages. This little app addresses that deficiency.
• Holding down the back button on the right hand edge of the device launches the Camera app for taking pictures.

If you want to sync data between the phone and the computer, you can use ActiveSync on Windows XP, or Windows Mobile Device Center on Windows Vista. WMDC replaces ActiveSync, but is still in Beta 3 as of right now.

You'll probably want a few apps on your phone. Remember this is Windows Mobile 5.0, not PocketPC, so be sure to pick the right version of the app. I highly recommend starting with a freeware registry editor such as PHM Registry Editor. There are a lot of cool settings that are only exposed through the phone's registry*. I installed "regedit.Stngr_ARM.CAB" on the blackjack and it worked fine for basic registry editing. Once of the first things you'll want to do is turn off the "application lock", either via editing the registry or by downloading and running a small registry edit file named "appunlock.cab" on your phone.

Battery life is OK, but not great. That's probably why it comes with an extra battery and a standalone battery charger out of the box. The phone does trickle charge over USB when it's connected, however, I couldn't get it to charge at all via USB when the battery was very low and the phone wouldn't turn on. There are pictures of the extended battery in action here. This might be a good upgrade if you're running into battery issues.

The phone has a lot in common with the Motorola Q, so often tweaks and files for the Q will work on the Blackjack. You can download new start page designs that work fine from koodezine and qusers. Here's the one I'm using:

And remember, the phone accepts MicroSD cards for additional storage-- they're tiny compared to their SD and MiniSD brethren.

* that's right, there's a Windows Registry on a phone. Depressing but true.

Optimizing Your Wallet

My coworker and erstwhile twin, Matt Hempey, turned me on to the superthin All-Ett wallet. I was in the market for a new wallet, as my current Tumi wallet was almost 10 years old and starting to show its age.

After seeing Matt's All-ett, I was sold. I ordered my own All-ett. As promised, the fully populated All-ett is thinner (much thinner!) than my old wallet is empty. Amazing! It's so much more comfortable to sit down with this in my back pocket. I no longer feel motivated to remove my wallet from my back pocket when I sit down. That's important, because I tend to forget where my wallet is when I remove it and leave it lying around.

I only have three minor criticisms:

• The ultra-thin spinnaker sailcloth they use is a tiny bit "crackly" in use. It's not a problem in practical use, you can't hear yourself sit down, but it is a little disconcerting at first.
• The orientation of the pockets means the contents tend to fall towards the middle when you open it. It's a little more fiddly than a "typical" wallet when opening it and fishing items out of it. But given that I tend to open my wallet maybe 3-4 times per day, at most, that's a tradeoff I'm perfectly willing to make.
• The color selection is absolutely hideous. Black works fine, of course, but you can tell this is sailcloth when you look at the color selection. Would you like your wallet in teal green, seafoam green, or kelly green? That's what I thought.

Minus those very, very minor criticisms, highly recommended.

I've always wished I could carry a pen on my keychain, but I've never found one small and convenient enough to add to my existing keychain. I already carry quite a bit of stuff on my keychain: a LED flashlight, a Leatherman Squirt, and of course my keys. I'm not sure if I want to add a pen to that list. But there's a better way: I can carry a pen in my wallet!

I found two wallet pens that worked:

The Derringer Wallet Pen is only $8. Unfortunately, it was slightly too large for my old wallet at 4" long. So I had to give it away.

The wallet pen is quite a bit more expensive at $40. But it's made of sterling silver, and most importantly, it's only 3" and even thinner. So it's even more portable.

The wallet pen, as small as it is, fits perfectly in the "crease" of a typical wallet. It does bulge up a tiny bit in the super thin All-ett, but it still works.

I'm very happy with my new wallet arrangement. It's more comfortable, it's way thinner, and now I always have something to write with, too!

Stopping real, physical mail Spam

All the email systems I currently use are extremely effective at blocking spam. Less than 4 spam emails arrive in any of my mailboxes in a given week. It pains me to say this, but I now get more physical mail spam than virtual email spam!

So how do I stop this avalanche of physical spam?

A good place to start is through the non-profit site JunkBusters:

1. Register your phone number(s) in the National Do-Not-Call Registry at http://donotcall.gov (for more information on the Registry, see our news page.)
2. To reduce the amount of junk mail you get, tell companies ``don't rent or share my name.''
3. You can ask the Direct Marketing Association to tell its members not to mail or call you.
4. You can ask list vendors and credit reporting agencies not to sell your name.
5. You can issue a ``Prohibitory order against sender'' to stop any junk mailer you object to.
6. Junk faxes are illegal; you can tell the sender they are risking prosecution.
7. Handling junk emailers generally requires very different tactics to mainstream marketers.

Unfortunately, it now costs a dollar to list yourself with the Direct Marketing Association stop list. It's not very much money, but the principle of the thing is offensive-- it feels like extortion; I have to pay people to get them to stop mailing me.

There's a little bit of Vertigo in every copy of Windows Vista

Vertigo Software did a lot of work on Windows Marketplace, which is featured very prominently in the Vista Welcome Center. That's the first thing users will see when they boot up their brand spanking new OS:

.. and we're also indirectly referenced in the new edition of Windows Media Center that comes with the premium editions of Windows Vista:

As I mentioned in an earlier post, Vertigo Software is named for the classic Hitchcock film of the same name.

Did I hear an Echo in here?

Chris Pirillo's 10 Ways to Eliminate the Echo Chamber is essential reading for any blogger.

The "Echo Chamber" effect is posting a link or a short snippet of an article without adding any additional content. Thus the same information is mindlessly echoed back and forth across the internet.

If you aren't adding unique information or content to your blog posts, you're essentially duplicating a social bookmarking site like digg or del.icio.us. It's what I call "lazy blogging".

Let's say Apple releases a new iPod, and you create a brief blog entry linking to the Apple site. Hey-- new iPod! At best you've created a news item that someone could read on any news website. At worst you've created duplicated noise, like the 30+ different hits you'll get for identical Wikipedia content that has been copied from site to site.

Whenever you post a blog entry, add some you. Tell us your experience with the iPod. Do some research and document exactly what's different about this iPod, and why you're excited about it. Share some tips on how you use the iPod. Let us know there's a person in there, not a link-generating, press-release-quoting automaton. That's the whole point of blogging!

What are YOU doing to get us out of the echo chamber?

The Mother of All Swiss Army Knives

I'm not sure if this is some kind of inside joke, but Wenger, the maker of Swiss Army Knives, recently introduced the mother of all Swiss Army Knives, the Giant Knife, Version 1.0:

The Giant Knife is $1200. It weighs 2 pounds, 11 ounces and measures 8.75 inches across. It includes the following:

1. 2.5” 60% Serrated locking blade
2. Nail file, nail cleaner
3. Corkscrew
4. Adjustable pliers with wire crimper and cutter
5. Removable screwdriver bit adapter
6. 2.5” Blade for Official World Scout Knife
7. Spring-loaded, locking needle-nose pliers with wire cutter
8. Removable screwdriver bit holder
9. Phillips head screwdriver bit 0
10. Phillips head screwdriver bit 1
11. Phillips head screwdriver bit 2
12. Flat head screwdriver bit 0.5 mm x 3.5 mm
13. Flat head screwdriver bit 0.6 mm x 4.0 mm
14. Flat head screwdriver bit 1.0 mm x 6.5 mm
15. Magnetized recessed bit holder
16. Double-cut wood saw with ruler (inch & cm)
17. Bike chain rivet setter, removable 5m allen wrench, screwdriver for slotted and Phillips head screws
18. Removable tool for adjusting bike spokes, 10m hexagonal key for nuts
19. Removable 4mm curved allen wrench with Phillips head screwdriver
20. Removable 10mm hexagonal key
21. Patented locking Phillips head screwdriver
22. Universal wrench
23. Laser pointer with 300 ft. range
24. 1.65” Clip point utility blade
25. Metal saw, metal file
26. 4 mm allen wrench
27. 2.5” blade
28. Fine metal file with precision screwdriver
29. Double-cut wood saw
30. Cupped cigar cutter with double-honed edges
31. 12/20-Gauge choke tube tool
32. Watch caseback opening tool
33. Snap shackle
34. Telescopic pointer
35. Compass, straight edge, ruler (in./cm)
36. Mineral crystal magnifier with precision screwdriver
37. 2.4” Springless scissors with serrated, self-sharpening design
38. Shortix key
39. Flashlight
40. Fish scaler, hook disgorger, line guide
41. Micro tool holder
42. Micro tool adapter
43. Micro scraper-straight
44. Reamer
45. Fine fork for watch spring bars
46. Pin punch 1.2 mm
47. Pin punch .8 mm
48. Round needle file
49. Removable tool holder with expandable receptacle
50. Removable tool holder
51. Multi-purpose screwdriver
52. Flat Phillips head screwdriver
53. Flat head screwdriver bit 0.5 mm x 3.5 mm
54. Spring loaded, locking flat nose nose-pliers with wire cutter
55. Phillips head screwdriver bit 0
56. Phillips head screwdriver bit 1
57. Phillips head screwdriver bit 2
58. Flat head screwdriver bit 0.5 mm x 3.5 mm
59. Flat head screwdriver bit 0.6 mm x 4.0 mm
60. Flat head screwdriver bit 1.0 mm x 6.5 mm
61. Can opener
62. Phillips head screwdriver
63. 2.5” Clip point blade
64. Golf club face cleaner
65. 2.4” Round tip blade
66. Patented locking screwdriver, cap lifter, can opener
67. Golf shoe spike wrench
68. Golf divot repair tool
69. Micro straight-curved
70. Special tool holder
71. Phillips head screwdriver 1.5mm
72. Screwdriver 1.2 mm
73. Screwdriver .8 mm
74. Mineral crystal magnifier, fork for watch spring bars, small ruler
75. Removable screwdriver bit holder
76. Magnetized recessed bit holder
77. Tire tread gauge
78. Reamer/awl
79. Patented locking screwdriver, cap lifter, wire stripper
80. Special Key
81. Toothpick
82. Tweezers
83. Adapter
84. Key ring
85. Second key ring

No USB memory stick? Boo.

Try putting that in your pocket. If you can find a pants pocket big enough for this thing, you should be ready for any possible situation that might befall you.

Visual Studio Debugging Tips and Tricks

Visual Studio has a ton of excellent debugging tools. There are so many, in fact, that it's easy to forget a whole slew of them even exist!

It might be a good idea to skim through these brief articles, just to be reminded of all the debugging goodness in Visual Studio:

• Peter Bromberg's Visual Studio.NET: Cool Debugging Tricks
• K. Scott Allen's Basic Debugging Features in Visual Studio 2005
• ASP Alliance Visual Studio Debugger Tips and Tricks

My personal favorite debugging trick isn't much of a trick-- it's the call stack window. And don't forget that Visual Studio 2005 adds Edit & Continue to the mix, too.

ClearType: Love It or Leave It

Vista will have ClearType on by default. IE7, until the latest beta, automatically turned on ClearType for all IE7-displayed content. And now, Office 2007 will also turn on ClearType:

If you are running on Office on Windows XP or Windows Server 2003, Office text is rendered with ClearType regardless of the system setting. This is because all of the Office fonts have been optimized to run in ClearType but most people don't know about the setting in the OS. If you don't wish to use ClearType, you can turn it off here and Office will follow the system setting. If you are running Windows Vista, Office will always follow the system setting.

I like ClearType-- it increases the effective horizontal resolution of computer displays by 3x:

It does this by leveraging the arrangement of RGB subelements in a LCD display. It's basically "colorized" antialiasing:

Looks crazy, but you have to see it in context on a LCD panel to understand where those extra pixels are coming from:

All the new Vista fonts are drawn with ClearType in mind.

The new fonts are hinted to produce optimal results if, and only if, ClearType is enabled. Unfortunately, this also means that the Vista fonts look truly awful with ClearType turned off. It's looking more and more like I better love ClearType!

I don't mean to sound ungrateful, because there is at east one set of experimental evidence that proves ClearType is more legible:

Overall, the study participants read the ClearType sentences statistically reliably faster than the sentences rendered in black & white (called aliased here). The magnitude of effect is approximately 5%. From the figure it’s clear that while ClearType improves both italic and normal (Roman), ClearType has a larger improvement on the italic text.

Although ClearType has "clearly" won the war, there are still a few edge conditions where ClearType doesn't look good:

• ClearType assumes a specific arrangement of RGB elements in an LCD screen. Fortunately, CRTs are pretty much dead; so most computer displays are now LCD by default these days. However, if your LCD supports rotation, eg, can be used in both horizontal and vertical orientations, ClearType will only work in the horizontal mode.
• ClearType is most effective when the text in question is black on white or white on black. Other colors work, but aren't quite as effective, because they interfere with the entire range of RGB colors available for the "colorized" hinted pixels.
• ClearType is particularly effective on small fonts, but not so much on large fonts. On small fonts, traditional black and white antialiasing is too granular and produces fuzzy results. That's why standard Font Smoothing only "kicks in" for fonts above a certain size. ClearType, because it actually increases resolution, can be used on small fonts. However, for larger fonts, the difference between ClearType and standard Font Smoothing is marginal.

Some other resources on ClearType:

Sub-Pixel Font Rendering Technology
ClearType, CoolType: The Eyes Have It
Wikipedia entry on ClearType

Microsoft Office 2007 Cheatsheet

A month or so ago, Jensen Harris posted an excellent one-page cheatsheet for getting started with the new Office 2007 user interface. It's available in Word DOC and PDF versions.

This is particularly relevant today because a couple e-mails went back and forth asking questions about the new UI. And it's all covered in the one-page cheatsheet!

For expedience, and greater dissemination, I created quick and dirty HTML version of this excellent reference. So I saved the Word doc as HTML and ran it through my Word HTML cleaner. With a little extra touch-up, here it is:

The 2007 Microsoft Office system includes a new user interface designed to help make Office easier to use.
Here are five things to know that will help you explore and use your new software.

	Use the Ribbon to find and use features
	The Ribbon is the area at the top of the window which contains all of the features in the program. The Ribbon is organized into several tabs (such as Insert, Page Layout, and Review) which group related features together.
	Tip: To temporarily hide the Ribbon, double-click the selected tab or press Ctrl+F1 on the keyboard.
	Contextual Tabs show features related to the selected object
	Whenever you select or insert a picture, table, chart, or any other object, the specialized tools for working with that object appear as additional tabs in the Ribbon. When you click away from the object, the tools put themselves away.
	Tip: To quickly bring forward the Contextual Tabs for an object, double-click the object.
	Click the Microsoft Office Button to do something with your document
	The Office Button contains all of the features that are used to open or start a new document and to share, print, publish, or close your existing document. From the bottom of the Office Menu you can open the Options dialog box to change the way the program works.
	Open related dialog boxes by using Dialog Box Launchers
	Some groups in the Ribbon (such as Clipboard, Font, and Paragraph) contain a Dialog Box Launcher icon. Click this icon to launch the dialog box related to the features contained in the group.
	Put your favorite features on the Quick Access Toolbar
	The Quick Access Toolbar is the customizable place to put features you always want to have one click away. To add a feature anywhere in the Ribbon to the Quick Access Toolbar, right-click the control and click Add to Quick Access Toolbar.
	Tip: Add an entire group of features to the QAT by right-clicking the title at the bottom of the group.

1 Compact Fluorescent Light Bulb = 1 Nuclear Power Plant

I'm a big fan of compact fluorescent light bulbs; they use a fifth of the energy of an incandescent bulb yet produce the same amount of light. The resulting reduction in your electric bill can be substantial, particularly if you live in a state like California where electricity is relatively expensive.

I've seen several articles recently that highlight how significant the energy savings could be if every home in America switched to compact fluorescent bulbs.

A CFL in every Home = 1 Nuclear Power Plant

There are an estimated 110M households in the US, so if you replaced one 60W incandescent with a similarly lumen-rated 13W CFL (I'd estimate a distribution cost of $100M-200M), you'd save just over $4.1B in electrical bills over the lifetime of the bulbs ($0.10/kWh over 8000 hours). At 5 hours/evening of usage (~4.4yr), we're looking at almost a billion bucks a year. That's not a bad ROI.

A global switch to efficient lighting systems would trim the world's electricity bill by one-tenth:

The carbon dioxide emissions saved by such a switch would, dwarf cuts so far achieved by adopting wind and solar power.

"Lighting is a major source of electricity consumption," said Paul Waide, a senior policy analyst with the IEA and one of the report's authors.

"Nineteen percent of global electricity generation is taken for lighting - that's more than is produced by hydro or nuclear stations, and about the same that's produced from natural gas," he told the BBC News website.

The carbon dioxide produced by generating all of this electricity amounts to 70% of global emissions from passenger vehicles, and is three times more than emissions from aviation, the IEA says.

Replacing all the incandescent bulbs in your house with fluorescents might equate to the carbon dioxide savings in driving a hybrid automobile:

We can estimate the annual greenhouse gas savings from a Prius vs a Toyota Matrix, FWD, automatic. The Prius gets an EPA-rated 55 mpg, vs 31 mpg for the Matrix. Assuming 12,000 miles annually, it will save 169 gallons of gasoline per year. Since each gallon produces 11.1 kg of CO2-equivalent GHG emissions, the Prius saves 1,875 kg of CO2-equivalent annually.

I would guess each bulb can save you about 85W (100W-15W), so 15 will save you 1275W. If the lights are on 2400 h/yr (6.6h/day), they will save 3,060 kWh. Using a national average of 1.35 pounds of CO2 per kWh, this will save 4131 lb or 1,875 kg of CO2. So it doesn't seem like an unreasonable statement that the two are comparable.

CFLs aren't cheap, though. I've found the best inexpensive sources for CFL bulbs of various types are Costco and IKEA.

For example, we leave the kitchen lights on almost continuously when we're at home; that's five 60 watt bulbs. Replacing those with 14 watt equivalent compact flourescent bulbs equates to a 230 watt savings. That alone is enough to feel the difference on our monthly electric bill!

Code Monkey very simple man

Jonathan Coulton's song Code Monkey is not only funny but also musically quite good. Listen to the Code Monkey song in MP3 format. And here are the lyrics:

Code Monkey get up get coffee
Code Monkey go to job
Code Monkey have boring meeting
With boring manager Rob
Rob say Code Monkey very dilligent
But his output stink
His code not "functional" or "elegant"
What do Code Monkey think?
Code Monkey think maybe manager want to write god damned login page himself
Code Monkey not say it out loud
Code Monkey not crazy, just proud

Code Monkey like Fritos
Code Monkey like Tab and Mountain Dew
Code Monkey very simple man
With big warm fuzzy secret heart:
Code Monkey like you

Code Monkey hang around at front desk
Tell you sweater look nice
Code Monkey offer buy you soda
Bring you cup, bring you ice
You say no thank you for the soda cause
Soda make you fat
Anyway you busy with the telephone
No time for chat
Code Monkey have long walk back to cubicle he sit down pretend to work
Code Monkey not thinking so straight
Code Monkey not feeling so great

Code Monkey like Fritos
Code Monkey like Tab and Mountain Dew
Code Monkey very simple man
With big warm fuzzy secret heart:
Code Monkey like you
Code Monkey like you a lot

Code Monkey have every reason
To get out this place
Code Monkey just keep on working
See your soft pretty face
Much rather wake up, eat a coffee cake
Take bath, take nap
This job "fulfilling in creative way"
Such a load of crap
Code Monkey think someday he have everything even pretty girl like you
Code Monkey just waiting for now
Code Monkey say someday, somehow

Code Monkey like Fritos
Code Monkey like Tab and Mountain Dew
Code Monkey very simple man
With big warm fuzzy secret heart:
Code Monkey like you

I previously discovered Jonathan Coulton through his amazing cover of Sir Mix-a-Lot's "Baby Got Back." Which I also recommend highly.

He's also done background music for John Hodgman's readings of his book, The Areas of my Expertise. You may recognize John as the PC side of the "I'm a Mac, I'm a PC" ads for Apple Computer.

I pledge my allegiance to the human race

I know I'm more than a little late for the Fourth of July, but this essay by Howard Zinn was fascinating reading:

On this July 4, we would do well to renounce nationalism and all its symbols: its flags, its pledges of allegiance, its anthems, its insistence in song that God must single out America to be blessed.

Is not nationalism -- that devotion to a flag, an anthem, a boundary so fierce it engenders mass murder -- one of the great evils of our time, along with racism, along with religious hatred?

These ways of thinking -- cultivated, nurtured, indoctrinated from childhood on -- have been useful to those in power, and deadly for those out of power.

Zinn is, of course, the iconoclastic author of the People's History of the United States. To quote Matt Damon in Good Will Hunting:

Have you ever read Howard Zinn's 'People's History of the United States'? That book will knock you on your ass.

But maybe Groucho Marx said it best:

I sent the club a wire stating, PLEASE ACCEPT MY RESIGNATION. I DON'T WANT TO BELONG TO ANY CLUB THAT WILL ACCEPT ME AS A MEMBER.

A Love Letter to Microsoft PowerShell

As a long time fan of Windows Script Host, I've been following Microsoft's PowerShell (previously known as codename Monad) with great interest for a while now. PowerShell is a next-generation command shell that, believe it or not, puts uber-powerful UNIX shells like BASH to shame:

The name Monad comes from a philosophy called Monadism, a form of pluralistic idealism created by the 18th-century philosopher G. W. Leibniz, who also co-invented calculus. The idea behind Monadism is that the world is an aggregation of simple substances, the smallest of which is called the monad. The Monad product team is focused on this concept of composition, which drives the syntax, naming conventions, and many other aspects of this product.

In the context of Windows, Monad is a new shell and scripting environment. It makes use of small commands, known as Cmdlets (pronounced command-lets), which can be combined in rich and powerful ways to create a first class administration environment.

Monad itself is an environment that can be hosted within other applications, such as the new command shell, msh.exe. Monad is implemented as a DLL that you can host within your own applications, as well. You can create new administration tools on top of Monad (MMC snap-ins, for example, may eventually be layered on top of Monad), allowing you to use a GUI application to perform an operation, then use the script generated by this action to repeat the operation across multiple systems.

I'm currently working through the excellent Guided Tour of PowerShell with Release Candidate 1, and it's amazing.

PowerShell gets the highest compliment I can possibly give: everything works like you expect it to. It's totally intuitive. You'll ask yourself "hey, I wonder if this works", and the answer, nine times out of ten, is a resounding YES.

Who knew a command shell could be this exciting and innovative? And who knew that it would come from Microsoft, of all companies?

Highly, highly recommended. Get RC1* and try it yourself.

* if you work at Vertigo, no need to download; it's in the expected place on the Microsoft share.

You Are Officially Old Now

Here's a cautionary tale from the UK of teens subverting anti-teen technology:

A high-pitched alarm which cannot be heard by adults has been hijacked by schoolchildren to create ringtones so they can get away with using phones in class. Techno-savvy pupils have adapted the Mosquito alarm, used to drive teenage gangs away from shopping centres.

They can receive calls and texts during lessons without teachers having the faintest idea what is going on

The alarm, which has been praised by police, is highly effective because its ultra-high sound can be heard only by youths but not by most people over 20.

Schoolchildren have recorded the sound, which they named Teen Buzz, and spread it from phone to phone via text messages and Bluetooth technology.

Now they can receive calls and texts during lessons without teachers having the faintest idea what is going on.

If you're curious, like I was, about what this sounds like, here you go:

• MP3 of real mosquitos (592kb)
• MP3 of 18KHz sine wave (158kb)

I can hear the sound if I crank the volume really high, which is consistent with the article's statement -- A teacher would be able to hear the sound only from 1 meter away. Teenagers could hear it from much further away.