To truly prank somebody, you have to catch them off-guard. And where are people most susceptible to surprise?...

A small project motor and 9V battery power a pulley belt (rubber band) which is attached to a roll of TP. When pulled on, even slightly, a toggle switch is flicked and the TP rapidly dispenses! This prank requires a bit of investment, but the payoff is supreme!

Update 3/31/12: Wow, 10k views in one day! I didn't think this prank would be popular, but since it is I decided to update step 3 for those of you who actually want to attempt this. Good luck!
4/1/12: Successfully pranked my roommate with this today! This prank was immediately preceded by another great prank. Ah, it was a hilarious moment...

Step 1: Prepare the prank

The first step is to prepare the cardboard insert. This will allow a motor to turn the TP roll.
  1. Create a cardboard tube that is slightly smaller in diameter than a TP tube, but bigger than the plastic cylinder that the TP rotates on. I used an empty TP tube and cut out a section, then taped it back together
  2. Glue or tape a few small strips of cardboard to the tube.
  3. Insert the tube inside a roll of TP. It should fit easily and snugly.
to do this to the staff only bathrooms at a public high school would be priceless<br>
i just now put this into my parents bathroom with a pressure switch under the seat and the wires hidden as best as i can. Now all i have to do is wait for it. One other prank i did is plug in my wireless mouse to my parents computer and pretend to be using it on my computer.
Ah a pressure switch under the seat is a much more elegant trigger. good thinking
awesome 'ible! nice vid too, did anyone else watch the drunk guy sing bohemian rhapsody? it caught my attention.
Great idea! Now, you cold also try reversing the motor to cause the roll to spew out an uncontrollable stream of toilet paper (although it would most likely cost you a roll of paper).<br><br>Keep it up!
Yeah really... Did you happen to watch the video?
Ahh, my bad. I only watched the one where it went backwards and rolled itself up. Thanks for pointing that out.
Or April Fool's Day, if you prefer that version of the day. (more caffeine, please.)
What a thought for April's Fool Day!<br><br>Wonderful!
Hi-larious! Suggested mod: Design a circuit to roll it out a few feet and then reverse the motor to snap it back.
you so NEED one of these!!
Wish I'd seen this earlier! Excellent.. will save it for next year. Mwaa ha ha ha
this is SOOO going in my parents house tomorrow =D
Could we get a video of it dispensing all of the toilet paper? This is a funny prank!
Brilliant prank, good work!
You're not using the washrooms here the next time you visit the lab.

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Bio: I create project-based engineering projects for my after school program, which is what you see on Instructables. I also develop hands-on science curriculum for a ... More »
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