Laser tripwire water balloon prank

laser_tripwire_prank

Even though it’s a bit late for April Fool’s jokes, [Ameres] wrote in to share a project guaranteed to catch your friends (or enemies) by surprise.

Like us, he had some old CD-ROM drives sitting around and thought that there must be some way to put them to good use. He gutted one, saving the laser’s carrier unit for use as his mechanical trigger. He placed the unit above a doorway, soldered a pin on to the end of the laser carrier, and positioned a water balloon at the end of the CD-ROM’s rails. The laser carrier’s motor was then connected to a photocell located about half way down the side of the door.

He mounted a laser on the far side of the door, which is pointed at the photocell. Once the laser beam is broken, the CD-ROM motor is actuated, popping the balloon over the unsuspecting victim.

It’s not the most high-tech prank out there, but how high tech does a water prank need to be? We just wonder how easy it would be to attach one of these things to our cube at work…

Have any ideas as to how he can make a bigger splash with his friends?  Share them with us in the comments.

Comments

  1. Harley says:

    I’m curious how he learned to do this through a career in electrical engineering possibly?

  2. jeditalian says:

    well.. when i took apart my old dvdburner, i tore out the lasers and reassembled it as a ‘cupholder’ no idea how you’d mount a cd drive on a door supporting a bucket of water though.

  3. paranoid says:

    Using a DVD-R or BluRay-R laser to pop a water balloon would be more impressive and elegant..

    Or arranging a row or column of balloons to be popped in succession by a moving beam..

  4. Professor P says:

    I was expecting a laser to pop the balloon…

  5. holly_smoke says:

    Should have used a mirror to reflect the laser beam, that way he would have only had one box.

  6. Dax says:

    The question is, how high tech a water prank doesn’t need to be.

    A thin fishing line one foot from the floor and a simple paperclip hook that jabs the water balloon when the line is pulled would have been among the most elegant solutions.

  7. holly_smoke says:

    You could see it as a prank, r you could see it as a proof of concept.

    In the future the guy could end up with a government grant to set up his business recycling DVD and CR drive internals to be made into home security systems…

    Very sustainable and all that.

  8. qwerty says:

    I don’t know how much dangerous could be a CD-ROM laser beamed accidentally into an eye, but just to be sure I’d use instead an IR LED through a collimating lens.

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