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  1. Is the name ‘Unicorn Buster’ a result of malicious coworkers changing your background to pictures of unicorns when you left your computer logged in?

    I usually used hello kitty on mine.

    1. It’s more evil to take a screenshot of the current desktop and set that as the background. Then remove all icons. It usually takes a quite a while before the victim figures out why he can’t click on icons anymore.. :-)

    2. Or doing a NetWare send to all: “I am an idiot who forgot to lock before i left the terminal” and the ever popular unix prank of putting ‘exit’ in someones .login (or similiar) file :-)

  2. @Ross yea almost right. If you leave your computer unlocked someone will send an email from your machine proclaiming your love for unicorns. Normally goes out to the whole office.

    I’m still waiting for some parts, so I’ll hopefully have a finished prototype done in about 2 weeks.

    I’ve also designed and 3D printed cases for the key-fobs, I should post some photos.

  3. I’m throwing my $$ at the screen but it isn’t working. Why isn’t this a kickstarter? I can solder, but don’t have the right tools to solder SMD parts. I want this, preferably in a case.

  4. I’m highly interested in such a thing. Even thought about doing exactly this kind of thing myself when I first saw the nRF51822.

    Do you plan to have you keyfob constantly send or do you want to enable it with the button and have it then send pings until it loses connection?

    Do you plan to automatically unlock the screen if you get a connection again within a reasonable time (like an hour or so)?

    For what OS do you plan to write software? Do you plan to fully open source this?

    1. @Electronic Eel

      There are two parts to the project. The key-fob uses a nRF8001 proximity Bluetooth controller. The USB dongle side uses a TI CC2540 in a BlueGiga BLE112 module. Just note, the nRF51822 can’t run in the master/central role, it’s great chip for peripheral devices though.

      The key fob constantly sends. You can turn this off by holding down the button, the button is also used to sync it to a new master. There are two advertisement modes on the key-fob. Fast – for the first 60s after losing connection send broadcasts at 40ms intervals. After 60s this rate drops to once every 60s. Doing this should last about 18 -> 24 months.

      You can do what ever you want, but currently the USB side emulates a keyboard and when connection is broken(+ some timeouts) it sends a keyboard command the lock the machine, this can be configured.

      OS, all this is developed under Linux, but since it’s just a USB keyboard it works with any machine without additional software (that was one of the original requirements.) There is also a virtual serial port for configuration, probably just going to be a text interface to change config. There will also be a bootloader that will work with avrdude.

      I will eventually open source the code and hardware. But currently I’m not planning to sell this online, might sell it to a few friends at the office.

      1. Thanks for your answer.

        Wouldn’t the nRF51822 work for the keyfob? I thought you just need master/central on the pc.

        Using a USB HID-Keyboard on the pc makes it easy to lock, you just have to program the lock hotkey once and you are done, no software changes on the pc neccessary. But unlocking in a secure way is nearly impossible.

        Why not go for a HCI interface on the pc side. This should be easy to get running with a regular linux bluetooth stack. When you then make sure that pairing can just be done when properly authorized and there is no “accidental” re-pairing, it should be fairly secure and also possible to offer unlocking.

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