Picture of Prank Box
The prank box is basically a sealed wooden box with an electric bell inside that is activated by a key switch. Once it is turned on, a relay inside the box is latched and it cannot be turned off without knowing the secret trick (Spoiler Alert: magnets). Quite understandably, a completely sealed box with a ringing bell inside that doesn't seem to stop can quickly become maddening. It is very funny to watch people ponder the implications of the device, reluctantly turn it on, and then stress out when they cannot turn it off. It is even funnier to get panicked emails from your friend in Canada after you mail it to him without any explanation, and he decides to ignore the directions on the box and turn it on.

Step 1: Go get stuff

Picture of Go get stuff
You will need:

(x1) Laser cut 1/4"-thick plywood box template**
(x1) 6V electric bell
(x1) 4 x D battery holder
(x1) Reed switch
(x1) Latching DPDT relay
(x1) Key switch
(x1) 9V battery holder
(x1) 9V battery snap
(x1) 4-40 x 1/2" wood screws
(x8) 8" zip ties
(x1) 4" x 4" x 1/8" matte white acrylic
(x1) Black and red acrylic paint
(x1) 5-minute epoxy
(x1) 30-NF Fastbond contact cement
(x1) Wood glue
(x1) Masking tape
(x1) Red and black wire
(x1) Wood stain and 220 sandpaper (optional)
(x1) Shrink tube

**The laser cut template should be etched (when appropriate) and cut. The "DO NOT INSERT AND TURN KEY" shape should be etched and cut from 1/8" acrylic.
BenM125 months ago

I was working my kit up and am fairly new to this electronics, my bell rings as soon as I put the D batteries in, any thoughts on where I may of crossed my wires?

Make sure the key is not engage. Try again.
Greasetattoo5 months ago

How do you charge the battery?

Next version could be lower power, with a sound chip playing a Justin Beiber song on repeat.

djairjr5 months ago

Remove the word "NOT"and the bell is turned off.

djairjr5 months ago

It will be a good thing if the red "NOT" word is the deactivator. Maybe with a magnet sheet...

joshabgvghn5 months ago
I'd put it into a welded steel box, with shock mounts or foam padding so if its hammered or drowned it'll survive I'd add a reed switch which needs a super strong magnet to activate, not your average hdd magnet strong but something even stronger
GingerS6 months ago

Very interesting prank, i found a "prank" on stumbleupon, mixxloud dot com, you can troll your friend or enemy with beeps all day long, it's crazy!!

Oh nice prank I can keep my important things

Musicman413 years ago
I have another idea: oscillating solenoids attached to weights to make the box shake.
A weight attached to a motor is usually an easier solution.
Roshy101 year ago

If they shake it it should get louder

wow... i would hate to have you all you guys as my enemies

great ideas from all..

swim111 year ago
Rad man!
swim111 year ago
Wow you must be a good wood worker
jelimoore1 year ago

Try using the car horns from <a href="http://www.sparkfun.com/products/10966">Sparkfun</a>. That would be LOUD and hilarious...

mykiscool1 year ago

Use a steel box with security screws so they can't break it open lol.

they would try and drown it

gmessenger1 year ago
Lol! Great, just great! Our neighbours to the south are now starting to entertain themselves by sending us curious Canadians pranks through the mail... Lol! Good one, eh!
It needs three things.

1) A button that is labeled "Push To Turn Off" which does nothing.
2) A dummy cord, plugged into a wall outlet, which can (and will) be unplugged after the "Off" button is pushed.
3) A dummy battery that can (and will) be removed after the "Off" button has been pushed and the cord unplugged.
No the dummy batteries button and cord should make it permanently louder once tampered with or make it stop for a few seconds and start again giving a false sense of hope and relief
That's a good one..
The wall plug could be used to charge the batteries and
if you make it electronic:-
each time you try to turn OFF with the key or push the OFF button the volume, frequency and or pitch increases
or have the OFF button turn off for 3 seconds before it blasts louder...
Add a ticking sound with a blinking LED if it is unplugged or a count down timer
all my evil juices flowing as I am drooling
I work for an engineering firm... Are there any more button-pushing-prone people on the planet?
your evil :)
batman963 years ago
It's got the batteries to run for a week
It's simple
It's tough enough to take a beating
There's no expensive circuit boards to get damaged when it is thrown against the floor
And it's almost impossible to figure out

The only ting it needs is a computer socket type power jack to recharge the batteries

The only thing better would be a clock so when they get it they turn the switch and it does nothing, so they leave it sitting there, but after the switch has been turned it triggers at 2AM. (adjusted for their time zone) Imagine trying to get it to stop at 2 AM!
Or, better: They turn the key, the bell goes off. Some small button on the side or under the box, under a lid that needs to be unscrewed with some weird bit, stops the bell. PHEW! Found the button! Finally, peace!

A clock triggers the bell again at 2AM.

Don't blame me if you end up with an axe planted firmly in your skull though.
Also add a fake unscrewable panel with a set of AA's that do nothing when removed or even make it louder stressing the victim of the prank even more
Godash1 year ago
Awesome! I like it!
peny1231 year ago

my mom was scared

Did you have to move with your Auntie and Uncle in Bel Air?

lperkins3 years ago
The bell is nice, but did you know that if you take the chip out of one of those musical greeting cards (that used to be really popular and that you can still find sometimes) it will run continuously for approximately two and a half *years* on a single, alkaline C cell?
Not done that for ages!
I like to stick one of these into some sort of waterproof container (35mm film canisters etc) with only one hole for the sound to get out of the peizo - then throw it up on a neighbours roof into the gutter above their bedroom!
(not next door though!)
Fantastic idea :) If you can get it stuck inside the gutter down pipe that would be perfect. They'd have to remove the whole pipe to get it out!
That's awesome. But won't removing the chip remove the song as well? I think the song is more annoying than a flat tone.
You throw the card away and just use the chip. You don't need a 4X8" card to hold a chip and a speaker that are each the size of a quarter.
Ohhhhh... that's what you meant. I get it. Thanks for replying.
Xolin lperkins3 years ago
Hah ha ha ha!!! Now THAT would be a great long-term, insanity-driving prank!!!
darman122 years ago
Fantastic 'ible! I just don't have the woodworking tools required.
Whiternoise3 years ago
I have one word for this: Library.
Just imagine: you set it on the table beside your friend with the key, and act as if you are walking out. Hide behind a bookshelf and watch as he freaks out, frantically searches for a solution, and decides to just book it (no pun intended) out of there! SO funny!
Awesome :)
You could modify the box to look like a book. It should activate when removed from its position!
Well, with your idea it seems more like a set-up and less like your own stupidity led to the annoying noise. It's a cool idea though.
srilyk Muniosi3 years ago
To be fair, I think many (most?) people would equate picking up a copy of Twilight with stupidity ;)
twilight series....
T-K Whiternoise3 years ago
Oh you are bad but I do like your thought process:)
Dbro395 2 years ago
Your Evil just pure EVIL I tell you but I must say it scared the hell out of my friend I customized it a bit to my likings lol it cracks me up all the time. Lol
ryukyu3 years ago
How about a smoke detector instead of a bell? Seems like it would be much more annoying...
Yes, that is the perfect noise.
yapoyo2 years ago
How did mike react to the prank?
I was hilarious.

my revenge will be swift and unyielding
Rich1402 years ago
I bought the key switch from the "kit" doesnt seem to be right- theres no common.... am I doing something wrong?
randofo (author)  Rich1402 years ago
I have contacted Jameco (who puts the kit together) and they will help you get the right part.
exotictoad3 years ago
im making mine so you spin the box to turn it off;)
wheellan3 years ago
I think im going to try and get it to shock you when you turn it...
srilyk wheellan3 years ago
This would be incredibly easy - just hook up the switch to the capacitor poles from any one of those "make a stun gun from a disposable camera". Though maybe a milder shock would be appropriate. Unless the key is actually isolated, they tend to be a great conductor.

If you really wanted to be evil, do that but add the bell. Then require holding the key in the "on" position for a second or two to turn it off instead of the magnet. I'm not sure what you'd have to do to make the circuit work, but that would be super fun.
SteamCap srilyk3 years ago
oh that is a great idea
timbon773 years ago
I've decided to make one of these, but I plan to use a sturdier, more hammer-resistant box and I plan to omit the magnetic switch simply because it will be more satisfying to be able to say "oh, sorry, there's no way to turn it off"
randofo (author)  timbon773 years ago
Good idea. My initial plan was not to have one, but I was convinced to add one.
exotictoad3 years ago
i made it, I than had the idai to test it out. i could not turn it off. fun.
Rimwulf3 years ago
what would be funny is after they turn the key and let there guard down it would set off caps or poppers.
oldmechanic3 years ago
Pretty cool!
What tech shop do you go to?
Just for an extra twist, why not have, turn the key, a little beep comes out and an led comes on, then the bell starts if the victim tries to turn it off...
oldmechanic3 years ago
you could turn it into a thing that rings a bell for 15 seconds, and then, lets say, it does the most unexpected...
Lindie3 years ago
Funny! :-)
flamekiller3 years ago
I've gotta wonder how you could get this through the mail without getting in LOTS of trouble.

That said, favorited (on to my 80+ item Instructables project list it goes!) I think I'll build one with an aoogah-type horn in it.
-max-3 years ago
to further improve the concept, i would use a alarm or siren instead of a bell and put a gient flashing red lamp on it and many useless switches and buttons with there own flashing lights to confuse the victim

(the switches would not conect to anything other than maybe a small led light next to each one, and only the magnets would stop the loud siren and giant rad light)
I made one once with a siren. It had a trip wire that set it off, which then closed up so you could not stuff the trigger back into it. We froze it to the grond under a buddy's car... He could not get the box open and his kids were crying, the wife was unhappy and his neighbors were calling and complaining about the noise :) He destroyed the box with a hammer, but let us know how much he appreciated the engineering!
nerd123 years ago
this is evil... and that is why i am building one. :D great 'ible
I'd smash it the second I would realize that the bell wasn't stopping.
imark773 years ago
TV show ? S2
mikeasaurus3 years ago
It's been days and it's still ringing...MY EMPIRE FOR A MAGNET AND SILENCE!
-max-3 years ago
another idea is the huge glowing red button instead of a key, and says "DO NOT PRESS"
randofo (author)  -max-3 years ago
I was afraid something like this might get triggered in the mail. That would be bad.
-max- randofo3 years ago
one of those buttons that have a cover, like in deal or no deal.
danbeckr3 years ago
perfect application for inductive charging.
sprinter3 years ago
How about a real diary book labeled "private", hollowed out with an unlabeled, sealed bell box inside. When the cover is opened (and it will be), it activates the bell and cannot be silenced without the secret magnet method. Up to you to rig it up. One way to find out who you can trust! Better me careful, though, it may embarrass someone you don't want to!
mgilbert7543 years ago
But how do you change the batteries???
That was my very first thought.
Next version should have rechargeables/LiPo, with a connector to plug in the charger.
Also, the key should be always attached to the box with a string or chain, so that it doesn't get easily lost.
mtnredhed3 years ago
I wouldn't invest a lot of money in this box with expensive batteries. After about a minute, I'd be using a hand sledge to find out what was inside, or some other way to introduce Sudden Deceleration Syndrome (TM).
Spokehedz3 years ago
Amazing... You can mail batteries, various bits of wire, switches and a mechanical bell through the mail to another country entirely with no issues...

I can't mail a remote to my parents on the other side of town because it gets flagged as suspicious.

randofo (author)  Spokehedz3 years ago
You should have labeled the remote "media art box"
stumitch3 years ago
GREAT!!!! i am SO doing this next year with my group of grade 8 students. perfect combination of wood and electronics. thanks for such an excellent 'ible.
randofo (author)  stumitch3 years ago
I can give you Mikeasaurus' address. You can mail them all to him! ;-)
Did you consider laser etching the instructions?
randofo (author)  dustinandrews3 years ago
They are etched and then painted.
I meant etched into the wood. Sorry for not being clear.
This screams retribution prank!
davmaldo3 years ago
this could also work well with a drawer or cabinet you do not want opened
vulgrin3 years ago
Pretty funny. Though in this day and age I'd be really careful with who you sent it to. The last thing you need is to clear an office building when someone thinks its a bomb. :)
scoochmaroo3 years ago
Yet again one of the best things I've ever seen. Ever.
heathbar643 years ago
You are just EVIL!!