Annoy Your Enemies With The Hassler Circuit

January 29, 2015 by Rick Osgood 62 Comments

[Craig] recently built himself a version of the “hassler” circuit as a sort of homage to Bob Widlar. If you haven’t heard of Bob Widlar, he was a key person involved in making analog IC’s a reality. We’ve actually covered the topic in-depth in the past. The hassler circuit is a simple but ingenious office prank. The idea is that the circuit emits a very high frequency tone, but only when the noise level in the room reaches a certain threshold. If your coworkers become too noisy, they will suddenly notice a ringing in their ears. When they stop talking to identify the source, the noise goes away. The desired result is to get your coworkers to shut the hell up.

[Craig] couldn’t find any published schematics for the original circuit, but he managed to build his own version with discrete components and IC’s. Sound first enters the circuit via a small electret microphone. The signal is then amplified, half-wave rectified, and run through a low pass filter. The gain from the microphone is configurable via a trim pot. A capacitor converts the output into a flat DC voltage.

The signal then gets passed to a relaxation oscillator circuit. This circuit creates a signal whose output duty cycle is dependent on the input voltage. The higher the input voltage, the longer the duty cycle, and the lower the frequency. The resulting signal is sent to a small speaker for output. The speaker is also controlled by a Schmitt trigger. This prevents the speaker from being powered until the voltage reaches a certain threshold, thus saving energy. The whole circuit is soldered together dead bug style and mounted to a copper clad board.

When the room is quiet, the input voltage is low. The output frequency is high enough that it is out of the range of human hearing. As the room slowly gets louder, the voltage increases and the output frequency lowers. Eventually it reaches the outer limits of human hearing and people in the room take notice. The video below walks step by step through the circuit. Continue reading “Annoy Your Enemies With The Hassler Circuit” →

Using Facebook Ads To Prank Your Friends

September 19, 2014 by Rick Osgood 38 Comments

Most tech savvy individuals are well aware of the vast amounts of data that social networking companies collect on us. Some take steps to avoid this data collection, others consider it a trade-off for using free tools to stay in touch with friends and family. Sometimes these ads can get a bit… creepy. Have you ever noticed an ad in the sidebar and thought to yourself, “I just searched for that…” It can be rather unsettling.

[Brian] was looking for ways to get back at his new roommate in retaliation of prank that was pulled at [Brian’s] expense. [Brian] is no novice to Internet marketing. One day, he realized that he could create a Facebook ad group with only one member. Playing off of his roommate’s natural paranoia, he decided to serve up some of the most eerily targeted Facebook ads ever seen.

Creating extremely targeted ads without giving away the prank is trickier than you might think. The ad can’t be targeted solely for one person. It needs to be targeted to something that seems like a legitimate niche market, albeit a strange one. [Brian’s] roommate happens to be a professional sword swallower (seriously). He also happens to ironically have a difficult time swallowing pills. naturally, [Brian] created an ad directed specifically towards that market.

The roommate thought this was a bit creepy, but mostly humorous. Slowly over the course of three weeks, [Brian] served more and more ads. Each one was more targeted than the last. He almost gave himself away at one point, but he managed to salvage the prank. Meanwhile, the roommate grew more and more paranoid. He started to think that perhaps Facebook was actually listening in on his phone calls. How else could they have received some of this information? As a happy coincidence, all of this happened at the same time as the [Edward Snowden] leaks. Not only was the roommate now concerned about Facebook’s snooping, but he also had the NSA to worry about.

Eventually, [Brian] turned himself in using another custom Facebook ad as the reveal. The jig was up and no permanent damage was done. You might be wondering how much it cost [Brian] for this elaborate prank? The total cost came to $1.70. Facebook has since changed their ad system so you can only target a minimum of 20 users. [Brian] provides an example of how you can get around the limitation, though. If you want to target a male friend, you can simply add 19 females to the group and then target only males within your group of 20 users. A pretty simple workaround

This prank brings up some interesting social questions. [Brian’s] roommate seemed to actually start believing that Facebook might be listening in on his personal calls for the purposes of better ad targeting. How many other people would believe the same thing? Is it really that far-fetched to think that these companies might move in this direction? If we found out they were already doing this type of snooping, would it really come as a shock to us?

Rickrolling Remote Control Prank

September 10, 2012 by Mike Szczys 18 Comments

This device is a prank or gag that [Eric Heisler] came up with. It will intercept IR remote control codes and play them back after a bit of a delay. The example he shows in the video (embedded after the break) catches the television power signal from a remote, then sends it again after about thirty seconds. This shuts off the TV and would be extremely annoying if you were unable to find the device. Fortunately (for the victim), [Eric] included a piezo buzzer that Rickrolls after sending each code. Just follow that tune to find the offending hardware.

He chose to use an ATtiny10 microcontroller. It looks like it’s realizing its full potential as the six-pin package use all available I/O to control the IR receiver module, an IR led, and the buzzer. It runs from a coin cell without regulation and the circuit was free-formed on a tiny surface mount breakout board which hosts the microprocessor.

Fool Me Once… Or As Often As Possible

March 26, 2012 by Mike Szczys 45 Comments

There was a time when posting a fake story was fun for all involved. But in this age of constant trolling, it’s near impossible to pull it off with our savvy readership. Instead of letting you down with a really poorly advised how-to, we’re putting in a call to hear what you’ve got in your own bag of pranks. Consider this another holiday theme and tell us what you’re planning for April Fools’ Day.

As always, we’re looking for your own posts on the topic. We always want to give credit where it’s due so post your prank on your blog or other favorite corner of the interwebs and send us the link. Don’t have a place to put it? You can always start a thread in our project log forum, or check out this for additional spots to stake your claim.

In case you need some help coming up with something, we’ve got a few examples to get you thinking. You can go the route of fake video demonstrations like this Gmail gestures hoax, or the more recent Human BirdWings Project. But those require a lot of production time and a clever seed idea. Perhaps something really simple will go a long way with the roommates. We’re thinking soap covered in clear nail polish to prevent sudsing, or perhaps you want to reconfigure your router to render pages upside down. We can’t wait to see what you come up with!

Human-shaped Planes Troll NYC

February 28, 2012 by Mike Szczys 30 Comments

It looks like a genetic leap has unleashed the age of mutants, but this is really just a few guys trolling New York City with some custom RC aircrafts. The video after the break shows the fliers up close. They’re pretty much full size, we’d guess 5’10” from head to heel. The outstretched arms and body act as wings, while the legs act as ailerons and rudders. But from afar (or even a medium distance) it’s quite difficult to make out the flat surfaces… they look like office workers loosed from their cubicles. ~~Unfortunately we don’t have more than a flight demo to share with you. If you know where to find build info (or any extra details at all actually) don’t forget to send in a tip.~~ We wonder if these are the same guy who made the flying hero we posted back in July?

There’s another nugget of delight right at the beginning of the video. A sweet octocopter which looks much like this one was used to capture the aerial footage.

Continue reading “Human-shaped Planes Troll NYC” →

Prank Gift Keeps Curious Hands At Bay

December 19, 2011 by Mike Nathan 23 Comments

gift-prank

You all know that person.

The one who picks up every present with their name on it, shaking it before busting into their best Carnac the Magnificent impression. Heck, you might even be that person.

[Jason] was thinking about how to combat the gift shaker in his life and put together a simple prank that’s sure to provide him some enjoyment when the shaking and guessing commences.

He bought a premade audio module that stores about 20 seconds of sound, replacing the pushbutton trigger with a pair of wires that can easily make contact when the box is vigorously moved. Everything was carefully mounted in a gift box before being wrapped and set under the tree to surprise the eager gift shaker.

We definitely like the idea, since there are a plethora of ways to customize/enhance [Jason’s] work to fit your specific needs. Whether you go with the kitten/puppy in a box theme, or wire in an incredibly loud alarm, your resident gift inspector will never look at presents the same way again!

Continue reading to see [Jason] explain his gift prank in more detail.

Continue reading “Prank Gift Keeps Curious Hands At Bay” →

Vintage Camera Retrofit Perfect For Trolling Strangers

October 12, 2011 by Mike Nathan 22 Comments

vintage_camera_retrofit

[John] likes making things out of unusual junk, and decided to build something for the sole purpose of trolling others. He thought it would be funny to stuff a new digital camera into the body of an old, obsolete camera, just to see how people would react to it.

He considered several different cameras, including a bulky old Polaroid, eventually settling on a far more manageable Argus C3. The camera wasn’t quite big enough to fit his new digicam inside, so he built a mock body using black micarta. He attached the Argus’ front and back to his plastic box, then spent some time fitting his digital camera inside. He transferred knobs from the original camera to his new false body, adding to the authenticity, before taking it out for some test shots.

You can see the final result above, and we think you would be hard pressed to notice that there’s something amiss with his camera unless you spent some time taking a closer look at it. He says that it works well for the most part, and it’s definitely a conversation starter. People are always puzzled by the fact that he is using such and old camera, and doubly so when he tells them it can take about 4,000 shots before he has to “develop” his pictures.