Instructables

Mystery Beeping Prank

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The Mystery Beeping Prank is a device hidden in a hollowed out book that beeps intermittently at different frequencies. I made this because I am surrounded by a lot of incredibly creative people who have a penchant for pranking one another, and this seemed like the most subtly annoying thing that I could think of. In fact, I imagine this will be outright maddening for all those not in on the joke. Hopefully these people will have a good sense of humor about it, and not be too permanently scarred by the experience. It is all in good fun, after all.
 
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Step 1: Go Get Stuff

Picture of Go Get Stuff
You will need:

(x1) Arduino micro (Radioshack #276-258)
(x1) 40 pin socket (Radioshack #276-1996)
(x1) LM386 audio amp (Radioshack #276-1731)
(x1) 220uF capacitor (Radioshack #272-1029)
(x1) speaker (Radioshack #273-092)
(x1) Prototype circuit board (Radioshack #276-150)
(x2) AA x 4 battery holders (Radioshack #270-391)
(x1) Book
(x1) Rubber cement
(x2) 12" x 9" x 1/4" wood blocks

Step 2: Socket

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Solder the socket onto the circuit board.

Make sure to leave room for the LM386 chip.

Note: The schematic shown here applies to the next 7 steps.

Step 3: LM386

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Solder the LM386 chip onto the circuit board next to the socket.

Step 4: Capacitor

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Solder the positive lead of the capacitor to pine 5 on the LM386 chip.

Solder the negative lead to any free terminal.

Step 5: Wiring

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Wire the Arduino micro's ground pin to ground, and the VI (voltage in) pin to the 12V rail.

Solder pin 6 from the Arduino micro to pin 2 on the LM 386 chip.

Connect pins 3 and 4 on the LM386 to ground, and pin 6 to power.

Note: I made some of these connections with solder below the board.

Step 6: Battery Packs

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Connect the battery packs in series on the circuit board.

Connect the single red wire to the 12v power rail, and the lone black wire to the ground rail.

Step 7: Speaker

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Solder the red wire coming off of the speaker to the negative lead of the 220uF capacitor, and the black wire to ground.
skittrell2 months ago

Very clever idea, definitely have some people in mind to use on already...! I was just curious, as I was going to head up to Radioshack later today, how much did all of the parts cost you in total? (Except for the book) Thanks!

BGreenHVAC2 months ago
I want to build several of these and have them timed to make the sound at a slightly different time and a proximity sensor to silence when movement is nearby. The sound will "move" around the room away from the individual being annoyed.... Ha! Ha! Ha!
astral_mage7 months ago
go check out think geek.com why they beat u there! its called( annoy a-tron )
sealog4448 months ago
Love this project, starting making one last night to torment my brother. Since this is my first time posting I'll say this up front, I'm just trying to be helpful and not trying to offend anyone. I did notice some mistakes in the code, the "for" loop should read more like this "for( int i ; i < randomTime ; i++) { " and for the last line "randomTime = random(900,5400); " I image that most people on here would be fine, just looking out for those that wouldn't be. Thanks again for the great post, I look forward to using it a great deal.
v6konablue8 months ago
Im new to programming and having trouble. I copied and paste the sketch and verify. I keep getting "I is not declared in this scope". Referencing for(i = 0, i < randomTime, i++).
LaserDave8 months ago
Very cool project. I have been designing circuitry for this exact idea for a month or so, but I am using an entirely different approach. Since there are numerous ways to accomplish essentially the same thing, I'll briefly describe how I'm doing mine to give alternatives others may want to think about.

Mine is going to consist of one (or two) coin cells for power, a piezo beeper, and a microcontroller. The idea behind mine is to make it about the size of a quarter so it will be easily hidden. The microcontroller can be either the PIC12F675 or a PIC10F200 because they are small, the former is a DIP8 and the latter is a DIP6 or surface-mount package SOT23-6. The code will be simple, it will keep the processor asleep until it is told to wake up, beep several times within a 30 minute timeframe, and then go back to sleep until the next night at around the same time. The aim is to have a random number of "BLIP" beeps (say, 6 or less) to occur at random times at night, with a random length of time between beeps, for around a half hour to avoid detection.

Piezo sounders are very inexpensive, and its sound is very hard to pinpoint in a room, perfect for under a bed, above a picture frame, in a chandelier... almost anywhere will work because it's very small. The tiny microcontroller draws so little power while asleep that a power switch isn't needed, it will still last a year or more on a pair of coin batteries. Once I get it finished and field tested, I will eventually make an instructable for it.

Peace!
wingerr8 months ago
Maybe make it more stealthy and maddening by using some kind of proximity sensor like an ultrasonic ranging device, so it'll stop beeping when the person approaches it. As soon as he gives up waiting for it to sound off again and walks away, start beeping anew.
Shades of crickets!
DaniloDara8 months ago
Once Elektor pulished some "Electronic Nuisance", which was easier, but included a phototransistor in order to silence the disturber when the light was lit, and start it again after some five minutes of darkness.
hmmm....
interesting added value.... :)
Excellent, other than the part where you destroyed a perfectly good book. grr
Lindie8 months ago
You're too funny! At it again! :-)
Titankeepr8 months ago
Very nice!
mikeasaurus8 months ago
If this ends up in my mailbox, Randy...
poofrabbit8 months ago
Oh this is just plain funny! I can think of so many people I'd love to do this to! Voted!
randofo (author)  poofrabbit8 months ago
The person I really wanted to get with this discovered my plan. I just have to wait long enough for them to forget.
M.C. Langer8 months ago
Wait a moment... When we moved from 2nd Street, I saw that book and I wanted to keep it, but I said "Nah. I have enough books to read, and somebody will learn more reading it". But you destroyed it and you are using it for EVIL!!!

Great project! :-)
randofo (author)  M.C. Langer8 months ago
Evil is a very subjective term.
Every villain thinks he is the hero of his story... LOL!
andrea biffi8 months ago
very funny! :-D
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