SparkFun April Fool's Prank Contest

Show off your prank skills for a chance to win!

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We love a good prank. The build up, the suspense - the final's just so much fun. Today we want to invite you to participate in the SparkFun April Fool's Prank Contest. Watch the video for more details:



Did you watch? No? Ok, well here are the rules or those who prefer the written word:

  • Send us a video of your best prank! The prank must use electronics (though not necessarily from SparkFun). Send an email with a YouTube or Vimeo link of your prank to
  • We will accept entries until 11:59 p.m. MT on March 31st, 2014.
  • The next day (April Fool's Day) we will post the top three pranks on our website - the winners will get $300 in SparkFun credit for first place, $200 in SparkFun credit for second place and $100 in SparkFun credit for third.
  • You can submit an old prank project if you want, but keep in mind points will be awarded for creativity, prank effectiveness (did you get 'em good?!) and your use of electronics.

But wait - there's more!

Don't have time to build a prank in the next week? No problem! Submit your idea for a great electronics based prank in the comments below. We'll choose one winner, and after April Fool's day passes, we'll build your prank idea and then film it in action at SparkFun HQ. We'll also send you a $50 SparkFun credit! We'll accept entries for this part of the contest until 11:59 p.m. MT on March 31st, 2014 as well.

Good luck - we can't wait to see your pranks!

Comments 57 comments

  • BiOzZ420 / about 10 years ago / 4

    Fluke claiming copyright on the color yellow ...

  • Member #369980 / about 10 years ago / 3

    Not a prank but a joke: Why is everyone so tired on April 1st?

    You would be too after a 31 day March!

    • LightManCA / about 10 years ago / 1

      Uggggh!!! [I'm putting this silly joke on my facebook]

  • Member #317608 / about 10 years ago / 3

    This one would be tough to build, but I think doable. Replace a coworker's mouse with a dummy that looks the same. The dummy has a built in IR proximity sensor to detect when the coworker reaches for it. When their hand is a couple inches away, engage a small motor underneath the mouse to make it drive out from under their hand and off the desk. The USB cable would have to be faked so that it looked attached, but actually wasn't. The main trick here would be the camoflage of the dummy mouse.

  • Tozian / about 10 years ago / 3

    Something tells me that car horns are gonna sell out soon....

    • Mr Earl / about 10 years ago / 1

      Fortunately, I've got four of them allready ;-) Inspired by Secret Agent Laser Obstacle Chess (, I once set up a laser diode, an Arduino and an LDR in the corridor at home. We had some guests at night and everybody got pranked.

  • darrylh / about 10 years ago / 2

    The prank I still might do one day:

    • Hook up a sensor to detect when the elevator door is closing (and maybe a PIR Motion Sensor to confirm that there are people on board)
    • Hook up a WAV Trigger and a set of reasonably loud speakers in the elevator lobby area
    • Play a sound of footsteps approaching, then a voice calling, "Hold the elevator!" at just the right moment

  • Member #241991 / about 10 years ago / 2

    A restroom sign that toggles between Men/Women each time someone passes into the restroom. It could be an electronic display like a paper display or electromechanical with moving shutters or a rotating body. It could be done with words or standard icons.

    • Member #96918 / about 10 years ago / 1

      This would be hilarious in a place where the restroom is used a lot by the same person.

  • pjhenault / about 10 years ago * / 2

    I live in a condo, and have thought about using an array of surface transducers to make the neighbor's walls talk. I've also considered using them with some sort of noise canceling circuitry to get rid of some unwanted noise.

  • Ford Anglia / about 10 years ago / 2

    Here's my million dollar April Fool's Prank idea. A shipping box is handed off to you but without warning it tips over and you (might) catch it. A few (random) seconds later it tips (randomly) again. When placed on the table it doesn't do anything. Pick it up and the game starts over.

    How does it work? The principle is simple. Just as a top heavy (or badly stacked) truck might loose its load in a fast turn, the trick shipping box has a top heavy weight inside. The position of the weight is moved by a servo, which in turn is driven by your favorite sensor (sound, light, heat, contact, proximity). Battery, sensor, micro-controller, etc. is left to the student to create.

    The deluxe version. If allowed to fall, the box makes a sound (scream, cursing, robotic 'warning, Will Robinson', or siren). Again, details left to the student's imagination!

    Icing on the cake The box has 'Fragile' 'Glass' 'Fire hazard" and other caution stickers. The return address is: The "Tippy Box Company" or "Earthquakes to go" (address is probably "One Bumpy Road, Shakey Town, USA" )

  • CrowDojo / about 10 years ago * / 2

    Probably overkill but I would suggest a box with hidden wheels in its base that slowly crept around the office making random stops for decent periods of time. Once it has paused it uses a some sort motion detection to move away from anything approaching it. Which allows it to peak interest and orient itself for maximum surprise. Inside the box is among other things an accelerometer so the creeping box knows when it has been picked up. Once the acceleration comes to a sufficient halt out from the box springs a creepy jack with a creepy laugh. If they haven't dropped the box by this point (assuming they expected something like this) it sprays them with a squirt of water.

  • Member #155489 / about 10 years ago / 2

    The best one I ever did: We saw someone using a small portable TV outside a window (NTSC at the time). We grabbed a signal generator and quickly found out the frequency for the channel he was watching. We would jam his TV, and get him to adjust the position and his antenna and then turn the siggen off. We had fun making him do all kinds of contortions to get his signal back.

    • Member #317608 / about 10 years ago / 1

      Stephen Wozniak mentions doing just this in his bio. Unfortunately, it doesn't work well now with most TVs being cable. Ah, progress! Why must you take away all our best pranks?

  • matt pinner / about 10 years ago / 1

    great ideas! i'm unleashing this blindingly bright delightful Goggly Eyed surprise :

  • Mezeaa / about 10 years ago / 1

    This brings me back to the electronics lab at college, where people would play really really evil pranks by messing with each other's circuits. Removing one little jumper (or replacing perfect ones with internally broken ones) in a hugely populated breadboard, wiring "instant short circuit" push buttons, substituting a 10k resistor with a 330 one in a R-2R DAC, were some of the meanest ones.

    My prank idea follows the same train of thought. It basically consists in hacking an FTDI cable (or an FTDI breakout, but the cable makes it easier to hide) by adding a little 8 bitter (pic12f or attiny) that would send insulting/garbage messages (ala Sparkfun's insult generator) at random. This device would then be handed to a noob or an unsuspecting victim of course, making even the most simple Hello world example a confusing, frustrating mess.

  • Digisynth / about 10 years ago / 1

    I've been working on a very cool prank, but unfortunately I won't make it in time. Oh well, I guess I'll send it in next year. :)

  • Komrade / about 10 years ago / 1

    1.) Hang a little box with a speaker in an elevator. When you detect someone getting on the elevator (or the elevator stopping at a floor) have the speaker play a random related file from Portal's GlaDOS.

    Example: (Person breaks infrared beam or accelerometer delta indicates a floor arrival) the speaker plays "Hello, and welcome to the Aperture Science Enrichment Center," the next floor it says "Welcome to test chamber four." Have it pick a random file from an attached SD card every time a floor event occurs.

    GlaDOS's Wav files from the game can be found here:

    I started playing around with this and have random sound files playing from an SD, a small speaker+amplifier set-up, the problem is I need a reliable way to determine we've hit a floor/ had a door event and have just plum run out of time. There are any number of accessible parts of an elevator that act like a soundboard, pick your choice of temporary mounting.

    2.) Modulate whispers/audio onto a hyper-sonic carrier, rig up the speaker on one of those countless visual tracking systems to prank people that walk through various areas of the building. prerecord audio or hook up a mic and give your coworkers the heebeejeebees. When the hyper-sonic wave hits a dense medium it demodulates the carrier and the object acts as the "source" of the sound. Anyone nearby will think the sound originates from the person acting as the demodulator, and the demodulator will think the sound is coming from their own head.

  • birojow / about 10 years ago / 1

    Put a hidden camera behind the seat in a hairdressing salon, and take a picture of the hair of the victim before the haircut starts. While the hairdresser works, someone photoshop the picture, and put a big fail in the hair. When the work ends, the hairdresser uses a tablet in the frame of a mirror to show the victim the back of his head, with the photoshopped picture.

  • Member #96918 / about 10 years ago / 1

    You should create an in-line telephone ringer. Connect to the phone line and page the telephone ever so often, only to "hang up" on them. When they try to dial out, it goes to busy signal.

  • chienline / about 10 years ago / 1

    Well here is my idea: an arduino with a sound shield and a loud mini horn are hidden behind a wall clock. Two PIR motion sensors [PMSs] are hooked with the arduino, one facing diagonally to the floor and diagonally left/right from the clock [better near entrance/exit door] and the other facing diagonally to the floor and straight in front of the clock. Maybe you guys a bit confuse with the aiming but I will describe my purpose. When someone detect by the first PMS, arduino behind the clock plays 'tick tock' sound as if we hear the clock's second hand ticking loud. When the person is looking for the sound around and out of the first PMS, stop the sound. He/she must be curious and keep looking. When they enter the second PMS, the one point to the floor straigt in front of the clock, again play 'tick tock' sound and maybe louder so that they figure out where the sound comes from and most of them will approaching the clock. If the second PMS trigger several tick tock [make a counter] then turn on the horn LOUD... GOTCHA! :-D

  • Bunk / about 10 years ago / 1

    Buy a dozen donuts at a local shop. Eat the donuts. Next you will need a magnet, a reed switch, a 10k resistor, an N channel FET, a car horn and a 12V battery. Attach the magnet to the top flap of the donut box, and a reed switch on the wall so you can detect when it is open (all inside the box so it can't be seen). Connect the source of the FET to the negative side of the battery. Connect the reed switch between the gate and source of the FET. Connect a 10k pull up resistor between the gate and the positive side of the battery. Connect the car horn between the positive side of the battery and the drain of the FET. Finally Label the box with "Free Donuts"

    When someone tries to open the box to get a donut, the horn will go off.

  • ImpressedbyRocks / about 10 years ago / 1

    Mini Vandergraf generator (clocked to 50 spins around to generate a decent shock) attached to a capacitor that instantaneously discharges it on the first unsuspecting victim that walks into a room. The door handle to the room would be the trigger. Make 3 and place behind random doors in the SF office so that people are scared of opening any doors at all.

    For extra fun, include a water gun that shoots before shocking for a more evenly distributed prank.

  • Member #421207 / about 10 years ago * / 1
    • Toothpaste in an Oreo.

    • Bullion cube in shower head.

    • Not electronic?: Capture the fun with a multi-use project: a portable voice record/playback device using SparkFun's Voice Recorder breakout (

      Or give a little lovin' to Teensy's Audio board ( Teensy would fly off the shelf as a tutorial (great platform that deserves more notice). You could even add a little modulation/distortion on the playback (chipmunk to James Earl Jones).

  • You use a couple (a Dozen) of heater pads and out them into a co-workers chair or a seat in the lunch room or the toilet seat (not quite sure how that would be done) and when someone sits on the chair it slowly heats up till it be ones too hot to sit on, you would have to be careful of fire danger. Could be reapplied to anything that's picked up or used regularly, anyone got a stuffed toy in the office?

  • Member #473769 / about 10 years ago / 1

    I once took an old infrared remote and used it to control an arduino project via an infrared receiver. If you can find the HEX codes that someones TV remote transmits, and then program an elaborate arduino project to respond to those inputs from the infrared receiver, you could have the project start making noise when someone pushes power, start moving when they change the volume, and maybe stop everything when they push some other button. You can even put multiple arduino projects that either all do the same thing, or different things given the same input from the remote. The only issue is that you can't hide the actual arduino project, the infrared receiver has to be in direct view of the remote. This project is funny because most people assume that their TV remote ONLY works with their TV and their is no way to have something else respond to it.

  • My prank that I would like to do is to make some sort of circuit using an Arduino Leonardo (or any other atmega 32u4 based board), such as a little tone() based piano with little push buttons for the keys, or something like that. It doesn't matter what project you make, because the whole point of your circuit is to get the person you are pranking to let you "power" the project with their computer's USB port. Really we just want to plug it into their computer so we can send keystrokes through the cable and mess with their computer, so you want the project to be distracting so it keeps their eyes focused on your electronics, and not their computer screen. Just imagine the look on their face when they stop playing with your cool project to see that their desktop is now filled with empty folders called "New Folder (n)" (Win+D brings you to desktop, ctrl+shift+n creates a new folder in windows 7) or if you want to be really mean you can send a shutdown command into the command prompt window. I'm working on something like that now and I'll upload a video for the contest if I have time. And for those of you who want to make one for yourself, make sure you use the serial monitor as a substitute for the keystrokes until you get your code entirely debugged. I didn't do that and I ended up accidentally shutting down my computer several times before I got it fixed.

    • Here is a quick demo of the folder creating I was talking about.

  • Thetinkerer / about 10 years ago / 1

    I always had this idea of putting an led matrix display over the bus-stop's one, and showing alarming or strange messages over the real one. It could freak people out and make a great video if caught on camera :)

  • thomc / about 10 years ago * / 1

    Some ideas:

    • Glitter gun: inflate a balloon, keep end closed with a servo, attach to a hollow tube filled with glitter, house inside a box file with a hole (or similar). Remotely activate to fire over a colleague at their desk.
    • Announcer: Wave shield or similar, remotely activated, add rude phrase, house in a box file and ask victim to deliver it somewhere. As they get near people activate the announcer. Bonus: willing accomplice who pretends to be offended.
    • Loud USB drive: house a personal sonic alarm inside a USB drive enclosure so that when plugged in it activates.
    • USB Banger: house a banger inside a USB thumb drive so when plugged in it goes off. Could use an exploding resistor with high current cap or dedicated banger/rocket igniter.
    • Bad backup: modify USB HDD housing so that it contains a spring and lock, and can be remotely activated to eject the HDD out of the end. Give this "critically important backup" to an intern, and as they walk off activate and the HDD goes flying.
    • The Internet: create a box that contains a copy of "The Internet" ala IT Crowd sketch. Ultrasonic sensors so it makes noise if you get near it, lights, humming sound, the works.
    • Sound splicer: For colleagues who plug headphones into their PC. Splice a sound generator into their audio jack inside the PC. When they are concentrating play some really loud adult content. They won't be able to stop it. Or just play a second or two randomly.

  • Dragon88 / about 10 years ago / 1

    Get the dogs involved by building a remote control doggie prank machine. A static device would be cool, but a bot that is able to drive around pranking pups would be best. Some ideas for pranks:

    1. Put two ball launchers on it. One shoots a real ball for the dogs to fetch, but the second launcher shoots a ball on a string that gets pulled back in very quickly.
    2. A tasty treat on a servo arm that gets pulled back into the machine quickly, making it disappear.
    3. A tennis ball or something else inviting that causes a loud noise to play if it gets pawed. (Nothing too scary)
    4. Anything else people come up with

    Every good sport should be rewarded, so maybe put a treat dispenser on it to give out goodies after the prank is pulled.

    • LightManCA / about 10 years ago / 1

      This reminds me of a past time called "Raver Fishing" at Burning Man.Someone attaches a glow stick or some fancy blinky thing to some fishing line, puts it out in the road, and waits for someone to try to pick it up.When the mark tries to pick it up, it of course gets yanked out of reach, the idea is to "reel" said raver in.

      I think some sort of automatic mechanism for doing this would be grand. I suspect to catch a sparkfunner you would just have to attach a pro mini to the end of it. Since the fishing line is easily seen during the day, put it in the parking lot at night. maybe put a coin battery and bright LED on it so that they have something to see.

  • healthyfatboy / about 10 years ago / 1

    I don't have the wireless modules or enough hardware to pull this off but along the lines of terror-min or annoy-a-tron, you could make them all wireless and control them from a base controller. Before someone gets to work, place them all around the office. Once they're in, have a different one beep periodically on your command. As it gets more annoying, keep moving the beep around. If you have say, 8 different beepers, it would take quite a while and a lot of beeping before everything was found. You could even space it out to beep once every 5 minutes to make it difficult to find any of them as the beep would change location each time and is spaced too far out to find. I know I'm ticked off when the batteries on my CO or smoke detector starts to go out in the middle of the night and it only beeps every 30 seconds or 60 seconds. I have to go chasing around the house figuring out which one it is in the dark while half-conscious and that's with 6 of them in the house where I know the location of each one. Imagine the confusion and frustration if you could make 10 of them beep at your will AND your victim had no idea where they were beeping from.

    My other idea is to discretely gather everyone's cell phone that leaves it out in the open, find out what ringtone they use, then download each ringtone to an MP3 shield. From there "ring" one phone and put the shield in some hard to reach location or something that would require some effort to get to, only to find a ransom note for the actual location of their phone. You might get something cool out of it.

    • jma89 / about 10 years ago / 1

      My other idea is to discretely gather everyone’s cell phone that leaves it out in the open, find out what ringtone they use, then download each ringtone to an MP3 shield. From there “ring” one phone and put the shield in some hard to reach location or something that would require some effort to get to, only to find a ransom note for the actual location of their phone. You might get something cool out of it.

      This. All of this. Evil...

  • Member #528124 / about 10 years ago / 1

    A prank i'm going to do is take; some distilled water, glycerin, a silcon nitride igniter, battery pack, 315mhz transmitters, arduino pro mini, "or any other kind of micro controler" a bottle, and a targeted room. while the person is taking a restroom break or something. fog them out!!! place mini bottle fog machine in office before the day starts then set it off from your office with another micro controler and transmitter. additional idea is to switch out there lights with black lights!

  • ME heat o nator / about 10 years ago / 1

    Dress a beetlebot ( up like a rat and let it free in the break room at work.

  • LightManCA / about 10 years ago * / 1

    Thinkgeek makes 2 "annoyators".
    * A USB dongle you plug into a computer. Looks almost just like a flash drive. Its job is to send random mouse movements and key presses. The frequency and type (mouse movements, key presses, or both) can be set with little switches and dials on the side of the devlce. * Another is an occasional noise generator, that will send out random short noises in a way that it would be hard to find the device making the noise.

    Making a random noise generator that was triggered by proximity, movement, or even a noise (like say a drawer being shut) would be fun. other ideas would be a guard drone... a little quadcopter that was designed to keep entry from a particular space, like the bosses office, kitchen, or... restroom? Or how about a device that would randomly lock a door. One minute the door works, and the next... it doesn't. That may be hard to conceal though.

  • OldFar-SeeingArt / about 10 years ago / 1
    • Hard to do these days... but back when dinosaurs walked the earth, people used CRTs for computer monitors. A bit of work could reverse the wires going to the magnetic coils on the neck of the CRT and the image would then be reversed left to right. A small toggle switch mounted on the back of the case made it lots of fun...
    • Now days, this hack is replaced with a screengrab and then use the image as desktop wallpaper. "Hey, my mouse doesn't work! The cursor is frozen!"
  • Anachronomer / about 10 years ago / 1

    It would be fun to use an Arduino Leonardo's HID functionality to create a device that would infrequently inject small random mouse movements and errant keystrokes when plugged in and hidden behind a computer. The spurious HID events would need to be infrequent enough that the user wouldn't immediately think something was intentionally being done, but rather that their keyboard and/or mouse were acting up.

    That's all been done before though, so the real prank is this: Hook up a lift/shake detector (accelerometer or the like) and a loud horn/buzzer inside the enclosure. When the object of the prank decides to investigate, hopefully they will find and pick up the device (rather than just unplugging it) at which point, it would blare the horn until they get their wits about them again and disconnect it. Putting a battery in it to keep making noise after they disconnect it is maybe a step too far. Maybe.

    • M-Short / about 10 years ago / 2

      When Tim our techsupport manager got back from his travels last month we did exactly that. We left him a box of "returns" on his desk to sort threw. One of the top boxes had a couple of rare earth magnets in the bottom right under the box was a reed switch, Arduino and car horn. When he pulled out the box the car horn went off. Apparently we've pranked him too much because he just kind of stared at it funny.

  • MirithD / about 10 years ago / 1

    A small device that will emit a short beep every 10-30 minutes (preferably at random), to be hidden in a coworker's desk.

    • Or SparkFun's Terror-Min is good too...

    • dbc / about 10 years ago / 1

      Ohhh... a friend and his roommate did that in college. Except the short, barely audible beep was once every 20 or so hours, and the device was hidden in the victims' room behind the light switch plate. They installed it, and for the next couple of weeks waited for it to be discovered, and then forgot about it. Then..... several months later.... they are sitting in the victims' room BS'ing... and the hear a faint "beeeeeep".

      The two victims jump to their feet, and with some agitation, say to them each: "Did you hear that? Did YOU hear that???? ARRRRGGGGHHH!!!! MISSED it AGAAAAIIIIN!!"

      Pure evil.

      • Brodie / about 10 years ago / 1

        We did the low tech version to a friend... We went to the pet store, to the reptile section and bought 2 boxes of live crickets. These cricketts where then released in his house, predominantly the bedroom.

      • l0gikG8 / about 10 years ago / 1

        In an office with computers and cell phones, random beeps are ignored. But the cricket sound has everyone trying to find the little bugger. Comedic gold!

  • ME heat o nator / about 10 years ago / 1

    I would love to see a dog collar or disposable camera hidden into a toilet seat. It could be triggered by sound like the dog collar or simply contact. The trouble comes from the issue of a camera in the bathroom. Maybe audio of the victim screaming would be enough!

    • ME heat o nator / about 10 years ago / 1

      Sorry... to clarify, the disposable camera would be used for the large capacitor that could quickly discharge into the unsuspecting sitter.

      • I'm just going to go ahead and say...we will probably not shock people when they sit on the toilet (and film them). Some might consider that a bit of an invasion of privacy.

        But keep the ideas flowing!

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