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How To (Un)Lock Your PC By Being Nearby (With a Bluetooth Phone)

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Imagine: you walk into your room, sit in front of your computer, and it unlocks itself. You finish what you’re doing, walk away, and it locks itself. No, it’s not magic – it’s Bluetooth and it’s easy to set up!

What You’ll Need

  • A computer with a Bluetooth connection
  • A phone or other device that can connect via Bluetooth
  • Either the Microsoft or WIDCOMM Bluetooth stack (for Windows)
  • Appropriate software

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Essentially, you’ll have to pair your device with your computer so that the computer can recognize its MAC address, and allow both the computer and your phone to be “discoverable.” Then, the respective software for each operating system should take over from there, locking the computer. Each method should use the OS’s default locking mechanism, no fake proprietary garbage here. Additionally, you should be able to use any kind of device that will connect via Bluetooth. I’ve only used smartphones – an iPhone 4 and a Droid X – so I know they work for sure, but there are various reports online of success on OS X and Linux with Wii remotes and other devices.

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The Windows software, BTProximity, only works with the Microsoft and WIDCOMM Bluetooth stacks. On OS X, you need to have Proximity installed and configured to get this trick to work, but the actually execution is done by AppleScripts that you can find on the internet. If you don’t mind paying some money, Rohos Logon Key can use Bluetooth as well as USB drives to accomplish the same task, though it’s a little steep at $32 for a personal license. They also have an OS X version. The Linux software BlueProximity seems to offer the best package. You can tweak your settings a little bit better and it has support for distance approximation, too.

We’ll be doing a step-by-step guide for Windows, but it shouldn’t be too hard to figure this out on OS X or Linux. The same basic steps should apply.

Configuring BTProximity

Make sure you Bluetooth stack is running and your device is paired properly.

After you download and install BTProximity, it should be running automatically. If not, find it in the Start menu.

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Right-click the icon in the system tray and select “Configure…”

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You’ll see the main window pop up.

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The first thing you should do is click the “Install Unlock” button. Not doing this will still allow your computer to lock itself when you leave, but it won’t unlock when you get back automatically. You’ll see a little pop-up message when it installs successfully.

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Click OK and then click the “Manage Credentials” link in the Configuration window.

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You can type in your username and password, and select whether or not to remember it. Since I’m using this at home, I’m not too worried about security, so I checked that option. Click OK.

To choose your device, click on the “Select…” button in the Configuration window. My computer’s Bluetooth device had some problems finding things this way, so I manually typed in the MAC address of my phone in the field. This worked for me without any problems.

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You can change the polling time from the default of 90 seconds. If you decrease this too much, your battery may not last as long, so remember that.

Be sure to check the “Lock when device goes out of range” box, and adjust the number of attempts accordingly. Devices that cut out sometimes may need a higher amount of connection attempts before the computer locks.

Next, check “Unlock when device comes into range”. The “Fask Unlock” option will allow your computer to unlock as soon as the MAC address of your phone is seen.

Screenshot-W7 [Running] - Oracle VM VirtualBox

That’s it! Keep in mind that Bluetooth distances can vary depending on your surroundings. As such, it works very well for me at home – when I leave the room the computer locks, and when I enter again it unlocks. If you’re having issues, you may want to uncheck “Secure (Ignore unpaired devices)” in the Configuration window.


This a pretty simple setup that works pretty well for home use. I can automatically unlock my computer when I’m in any given room so long as I have my device’s Bluetooth connection on. Do you have a better way to log in? Have you thought of a better use for a simple trick like this? Share your thoughts in the comments!

Yatri Trivedi is a monk-like geek. When he's not overdosing on meditation and geek news of all kinds, he's hacking and tweaking something, often while mumbling in 4 or 5 other languages.

  • Published 07/7/11

Comments (29)

  1. jon_hill987

    Nice idea, but with the battery life of modern smartphones being what it is this seems a good way to make it even shorter…

  2. Steve K

    If the phone battery dies, is there a bypass that will let me login and still keep working?

  3. PCPIMP

    Pretty cool if it worked right :) Lock works perfect but unlock not so much :)

  4. শাওন

    Wow!!!

  5. TheMrBugz

    Just what I needed going to try it out now

  6. Arcanite

    @Steve K: It doesn’t prevent you from logging on without the bluetooth device. It just makes it more convenient and auto-locks/unlocks for you when you’re nearby. If the phone dies, just simply enter your password like you normally would. It’s not a lock replacement.

  7. Jurgen

    Mmmm… My laptop is part of a domain; however I enter my credentials, they are not accepted, and the user tile has a red text on it: ‘Event’. Any clues anyone?

    syntax used:
    1)
    2) @
    3) \

  8. Jurgen

    some automatic scrubbing in my message above…

    syntax used:
    1) username
    2) username@domain
    3) domain\username

  9. transcender

    I too can not get the unlock feature to work on my domain laptop? insights anyone?

  10. ericssonfan

    Unlock doesn’t work for me either.
    It would have been so nice though.
    Everyone in my non-tech-savvy office would have given a big ‘woooooow’…

  11. transcender

    i dont think its the most secure thing to have ur phone just unlock ur station but yah i’m annoyed it doesnt work. curious what the battery life impact is going to be

  12. Frank

    thanks

  13. Harshit Sethi

    I m facing problems with the unlock feature…I use Win 7 32 bit…any ideas??

  14. Brent

    Any solution for Windows XP? My company is still on XP and the BTProximity app only does Vista & 7.

  15. Tom T

    sorry for the OT (but not much)

    Converserly, what about some bluetooth keychain gadget to beep if you move away from your cellphone?

    This gadget would prevent a cellphone to be stolen or forgot

    It would be even better if the keychain gadget beeped and the cellphone rang, automatically, allowing the user to locate it

  16. Sikas

    it doesn`t work for me … it doesn`t find any device and it doesn`t lock even when I added my device address manually!!

  17. Cormin

    I always keep a bluetooth headset connected to my xperia play (im too lazy to hold the phone up to my ear, im on the phone too much haha..) would it still work when my phone enters the proximity while connected to my bluetooth headset?

  18. Sonusmac

    Awesome app… Its really good..

  19. Steve K

    Thanks Arcanite and others. Here’s the reverse question. If the phone battery dies, will it lock me out even if I log in manually?

  20. Victor Solis

    Has anyone tried BT Proximity on a machine that’s not in a domain? Perhaps it’s inability to unlock stems from having to press CAD prior to typing the password.

  21. Bessie Ball

    I paid $32.67 for a XBOX 360 and my mom got a 17 inch Toshiba laptop for $94.83 being delivered to our house tomorrow by FedEX. I will never again pay expensive retail prices at stores. I even sold a 46 inch HDTV to my boss for $650 and it only cost me $52.78 to get. Here is the website we using to get all this stuff, BidsG et.com …..

  22. Alex

    This is a fantastix application (the linux one) I used it with my phone and after about 3 minutes of fiddling with the levels and settings. This will be sure to give many of my friends a lovely nerdGasm :)
    Unfortunately it doesn’t work with my iPod 2nd gen, no doubt due to the first generation apple bluetooth on it, anyhow, a wonderful geeky app. Exactly what this site should be about!

  23. Shawn

    I downloaded BTProximity and Microsoft Security Essentials indicated a potential threat “Adware:Win32/Hotbar”. Has anyone else run into this?

  24. Stefan Zabunov

    Nice application, but I need it at work and we’re in domain. And, unfortunately, the unlock feature doesn’t work for me too. Would be nice if there is any solution!

  25. Jurgen

    I guess Victor Sollis is right: it’s the CAD which causes the problem. I seem to remember vaguely there’s some policy change you can make to disable the need for that…

  26. buddy

    I’m not able to find Bluetooth option in Windows 7. How to get the Bluetooth option.

    Would anyone assist me in this regard?

  27. Jared

    I’m having the same problem as Jurgen above and I don’t need to CAD before entering a password, any progress on a solution yet?

  28. AJ

    Cool but probably counter productive. First thing I would think if my flatmate showed this to me would be..

    ‘Challenge Accepted!’

  29. Otto

    What if your laptop is already locked? How do you unlock it?

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