Lock & Unlock Windows With Bluetooth


I’d love to automate as much as possible and also get some great UIs along the way (Minority Report / Iron Man anyone?). An article I came across from How To Geek was a step closer to the dream. Using a bluetooth device to lock and unlock your computer.

Why Bluetooth

Bluetooth is a short distance radio communication so this makes it ideal for detecting the distance. Wifi is a medium range so if it was employed for locking and unlocking the computer it will never happen till your out of the house or even further (which may work for some people). Near Field Communication and RFID are possible candidates but this is even shorter range than Bluetooth. Also it means having to touch in and out so that doesn’t work.


BTProximity by Dave Amenta is a free (as in beer) software for Windows which allows a Bluetooth device to perform certain actions when a Bluetooth device comes and goes from range of the computer. Actions available include:

The software monitors for a specified MAC address of a Bluetooth device. This device can be paired or unpaired with the computer. There are settings to control how often it polls to check if the device is still in range and the number of tries and timeout in milliseconds before it performs an action. The latter setting allows for interferences or bad connections between the computer and the device.

The poll time allow for more frequent checks but at the detriment to more power use of the device but can detect the device a lot quicker.

One of the limitations with the software is that the Bluetooth adapter on the computer must use Microsoft’s Bluetooth software stack. I’m currently using a Belkin F8T012 without the Belkin software installed on a Windows 7 computer which works.



One of the main cons for using this type of set up was the drain on the battery. I had tried to find a bluetooth device that was wearable and didn’t have to do much but connect to a computer. Alas there was hardly anything that existed.

Also sometimes the software failed to work and seems to not lock / unlock when the device is in range again. It constantly showed a red icon and I have only had it work once by selecting reset option from the right click menu of the tray icon.


The software works really well and does what it says. I’m fortunately enough to have a Bluetooth dongle which uses the Windows Bluetooth stack to enable the software to work. The icon in the task tray changes colour depending on if the device is detected within range or not. The only issue I have ran into, which may not be entirely the software’s problem is that it may unlock the computer when the Bluetooth device is within range but it does not wake my monitors up from standby. I know it has unlocked itself because Windows play the unlock sound and I can hear it through the speakers.

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

About Danny

I.T software professional always studying and applying the knowledge gained and one way of doing this is to blog. Danny also has participates in a part time project called Energy@Home [http://code.google.com/p/energyathome/] for monitoring energy usage on a premise. Dedicated to I.T since studying pure Information Technology since the age of 16, Danny Tsang working in the field that he has aimed for since leaving school. View all posts by Danny → This entry was posted in Security, Windows and tagged , , , . Bookmark the permalink.

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