Sure, you could opt for a laser tripwire that puts intruders on blast via Twitter, but there's something to be said for the simplicity of the latest security system to come from Instructables user EngineeringShock. You've seen this setup before: a group of mirrors are strategically positioned to bounce a laser beam across an open space, ensuring that even the most nimble of invaders -- excepting MacGyver, perhaps -- will set sirens blaring. Consisting of a programmable keypad, a laser and detector, a series of six carefully aligned mirrors, and an LED-equipped siren, the system does Hollywood-style security on a budget -- the siren being the most expensive element at $20. If you're looking to lock your stuff down like they do in the movies, follow the source link for full instructions, or check out the video demo after the break.