Smack Your Mac to Switch Spaces

Back in March 2005, Apple introduced a new feature to its laptops line called the Sudden Motion Sensor (SMS) to protect hard drive with the data inside it. This feature utilizes an accelerometer to detect a sudden movement (such as falling or heavy bumping) and then quickly lock the hard drive’s head if such condition is present.

But the geeks see this feature from different point of view – fun. Few “unordinary” SMS-based applications came to life. One of the favorites is Smackbook Pro which function is to switch virtual desktop every time user “lightly smack” the side of laptop’s monitor.

Knock-knock! Who’s there?

As time goes by, maybe the geeks decided that SMS is no longer fun, thus abandoned the development of many – if not all – of the applications. So most Apple’s newbies never knew that there were such cool applications available for their Macbooks.

Meanwhile, Apple developed its own version of virtual desktop called Spaces and put it as a part of Leopard.

I’m sure that here are a lot of people who realize that the same cool trick that was so popular before could also be applied here. But I only could find one – a dude called Chris – who takes some action to materialize the idea.

He created “Screen Knock” and made it available to public. To use it, you have to download the small (less than 300 Kb), install it, and adjust some settings.

Adjusting the Spaces Settings

In the video on the screen knock page, Chris explained that for his app to work, Spaces has to be set to work with the Command + Arrow (Left, Right, Up, Down) shortcut keys.

Chances are, the settings on your computer are different (such as Control + Arrow), so you need to check and adjust them. Here are the how:

1. Go to ‘System Preferences’ (Apple –> System Preferences) and choose ‘Expose & Spaces’.


2. Choose ‘Spaces’ tab.


3. Tick the ‘Enable Spaces’ checkbox.

4. Look at the lower part of the window and find the drop-down option box called ‘To switch between spaces’ and choose ‘Command + Arrow Keys’


Run the Screen Knock application and you are ready to go!

Wish List

When you open the ScreenKnock application for the first time, you are in for a surprise. There’s just a small empty window there. No instruction, no options, no preferences, no nothing.


Maybe Chris thought that the app needs nothing else but does what it is built to do: switch Spaces whenever you (lightly) knock the side of the Macbook. But…

If I may suggest something to add to improve this little cool app (and I hope Chris read this), it would be to add the option for ordinary users:
– To change the sensitivity of the “knocking”
– To choose what shortcut keys Spaces uses.

Reason: Sometimes it took me quite a knock to finally able to switch spaces (and I intend to keep my white Macbook for a little bit longer…) And, as a writer, I already got use to Command + Arrow keys as the mean to go to the beginning/end of the line/paragraph. So, with ScreenKnock application open, my writing workflow is disrupted by Spaces switching wildly every time I tried to move between my words.

Have you tried ScreenKnock? Are you familiar with the old Smackbook? Share your thought, experience and opinion using the comment below.

Jeffry Thurana Jeffry Thurana

Jeffry Thurana is a creative writer living in Indonesia. He helps other writers and freelancers to earn more from their crafts. He's on a quest of learning the art of storytelling, believing that how you tell a story is as important as the story itself. He is also an architect and a designer, and loves traveling and playing classical guitar.


  1. Hey dude, i’ve been using smackspaces for a while.
    it do has a calibration screen, and a star &stop button,
    but t also has 2b set to command + arrow keys to work

    It’s running well on leopard )10.5.6( and i’m pretty hapy with this

    A tip for you
    if u (i know ur in a white) r on an aluminium (MBP/MB unibody or a MBP) with multitouch the preference pannel multiclutch can save ur ass in those replaced key combinations.
    it let’s u add custom multitouch gestures to any app, so u don’t have to press teh shortcuts

  2. Just came and read, this is wow! I was seek from many blogs, but here is the best, I love it.

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