Doorbell hack makes coworkers less annoying

doorbell_wav_player

Hackaday reader [Sprite_tm] works in an office building that used to house several businesses, and as a remnant of the previous configuration, a doorbell sits in the hallway just outside his office. Several of his coworkers get a kick out of ringing the doorbell each time they enter the office. While not annoyed at the practice, he was getting tired of the same old “ding-dong” and decided to shake things up a bit.

He wanted to modify the doorbell to play random sounds when triggered, but he was pressed for time as it was March 31st, and he wanted to get it installed for April Fools’ Day. Without any real plan or bill of materials in mind, he pieced things together with whatever he happened to have sitting around.

He used a design borrowed from Elm-chan in order to play wav files from an SD card with an ATTiny85, and used an L293 H-Driver as an improvised sound amplifier. After sorting out some power-related problems, and configuring the circuit to be as stingy with its battery as he could, he declared the project complete. He originally aimed to deadbug everything on the metal sleeve of the SD card socket (which is awesome), but considering the size of the speaker and the battery he selected for the project, he ended up stuffing everything into a cardboard box.

We don’t care too much about how he packaged it, we just wanted to know what his co-workers thought of his doorbell augmentation. In the end, they loved it, but we imagine this doesn’t do anything to discourage any of them from hitting the doorbell multiple times a day.

Stick around to see a quick video of his doorbell hack in action.

[Read more...]

Adjustable prank box growls and screams

growling_altoids_tin

[Brett] over at FightCube was tossing around ideas to build a screaming prank circuit that fits inside an Altoids tin. Sound familiar? We featured a story just a few days back about the construction of a very similar item by [Dino Segovis]. It seems that great minds think alike after all!

[Brett’s] version is a bit more robust than the one we featured the other day. It’s similar to [Dino’s] in that it uses a 555 timer in astable mode, triggered by a normally-closed microswitch when the tin is opened. However, this version also includes a photoresistor which is used to increase the pitch and speed of the output as more light enters the box. This creates a growling effect that builds up into a scream as the box is opened. [Brett] has also included an adjustable pot which allows the sound range to be tweaked to his liking.

Stick around for a video walkthrough of the screamer circuit as well as a demo of the Altoids tin in action.

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Screaming Altoids tin just in time for April Fool’s

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Maker [Dino Segovis] has started on a project he calls “Hack a week” where he will be putting together one hack or project per week, for a full year. The first installment of his video series was finished just two days before April Fool’s, and appropriately enough covers the construction of a circuit you can use to prank your friends.

The “Altoids Screamer” is a simple circuit based on a 555 timer that he built into a standard Altoids Tin. The 555 timer is used to generate a loud pitched squeal whenever the tin is opened. This is accomplished by wiring up the 555 in astable mode, and connecting it to a speaker to output the sound. A micro switch is installed inside the tin to detect when the top has been opened, triggering the “scream”.

While it’s not the most complex circuit we’ve seen, it definitely gets the job done and is easy enough to build in time for tomorrow’s festivities. It is a great hack for the office, the library, or any other quiet place.

Continue reading to watch [Dino's] first Hack a Week video demonstrating the prank’s construction. If you are interested in some more of his work, be sure to check out this automatic ball launcher and this other 555 Screamer toy.

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Convert an old busted phone into a voice-altering prank machine

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Have you ever wanted to be someone else, at least over the phone? Do you dream of turning the tables on telemarketers, making them hurry to get off the line instead of you? If so, [Brad] over at LucidScience has the project for you.

A bit of a prankster at heart, he walks through the conversion of a normal telephone into a Data Access Arrangement device (DAA), allowing you to interface it with either hardware or software-based audio mixers.

The process can be completed in a relatively short time period, and doesn’t require much more than an old telephone, a handful of tools, and some miscellaneous switches and jacks. He disassembled a telephone and trimmed off all of the unnecessary circuitry while retaining most of the original functionality. Line in and out jacks were then installed in place of the handset microphone and speakers, respectively. The final result is a compact box that relays altered audio from any kind of mixing device to person at the other end of the call. Since the majority of the phone remains intact, your calls still sound natural as they pass through the phone’s existing voice filter and preamp circuitry.

Once the DAA is complete, you can use any number of effects on your voice, limited only by your audio mixer. [Brad] says he has long-time friends that don’t even recognize his voice after he has run it through his effects machine, so get started on yours before April Fool’s day arrives!

Screamer doll prank toy

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While it is only the middle of February, it might be a good time to start thinking about your plans for April Fool’s day. [Dino's] Screamer Doll is his submission to the upcoming 555 Contest.  This fun little circuit can be used to easily annoy your cube or house mates and is perfect for all of the April Fool’s day pranksters out there. He fit all the components into a small plastic toy, replacing the eyes and mouth of the doll with three photo cells, and swapping the nose out for a bright LED. When light hits the photo cells, a loud high-pitched squeal is emitted, and the LED blinks furiously until the light source is removed. Shielding the device from light will cause both the sound and LED to slow down, but the brightness of the LED ensures that the toy still makes noise when covered.

It would be great to see a version of this project that is completely silent in the dark, allowing it to be hidden at night, greeting its victims come morning.

If you want to see video of the device in action, read on – just be sure to keep your speaker volume at a reasonable level!

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Fabulous Magic 8 ball prank

Hackaday forum user [arfink] has shown us a brilliant practical joke he built. This is a magic 8 ball that will blind you with a flash when you flip it over. Have you ever been in a room with one of these and not flipped it over? Neither have we. Using a basic flash circuit ripped from a disposable camera in conjunction with a mercury switch, this project took him about 2 hours to make. Admittedly, most of that time was just trying to split the 8 ball in half without completely destroying it.  The circuit is pretty simple. Just figure out what 2 wires need to be crossed to trigger the flash and install your tilt switch there. He added a power cut off so you could disable it as well.

UPDATE: video added after the break! [Read more...]

Office prank: death from above

Unsuspecting office workers beware. You may already be in the cross-hairs of a ping-pong ball launching robot. This covert robot hangs out on the other side of a suspended ceiling, waiting for its operator to unleash the fury. When put into action a hatch in a ceiling tile is raised and balls are launched at a cowering cube-dweller.

It looks like the balls are launched at a reasonable speed and won’t hurt anyone. The next generation of this bot should do a better job of integrating the trap door and be quieter. This would be a lot more fun if the victim couldn’t figure out where the heck that ball just came from.

[via BotJunkie]