Fire Breathing Jack-O-Lantern Of Death

[Rick] is at it again, this week he has conjured up an even more dangerous Halloween hack. Thankfully [Rick] has included a warning of just how dangerous this hack can be, especially if children are around. Don’t do this hack unless you know what you’re doing and you can do it safely.

For [Rick]’s number four hack of the month he gives us the Fire Breathing Jack-O-Lantern of death! This isn’t a new idea but it is a very unique and simple implementation. We always love seeing the ingenuity of hackers to repurpose existing commercial products. In this case, [Rick] uses an automated air freshener which dispenses a flammable spray for the pumpkins breath if you dare get too close, but not so close as to get burned. The trigger distance is controlled by an Arduino and a Parallax Ping))) sensor so as to fire only when people are farther than 3 feet but closer than 5 feet. You can get a copy of the Arduino sketch from his blog posting.

A small candle is used to ignite the flammable spray, which shoots out 5 to 10 inches from the pumpkin’s mouth when triggered by the ultrasonic sensor. It couldn’t be simpler. The most challenging part was getting the large air freshener dispenser in the pumpkin with the flames coming out the mouth. A little extra whacking at the pumpkin fixed the fit, but planning for a larger pumpkin would be advised.

Theoretically the Arduino shouldn’t trigger and throw flames if people are too close, but when kids are running around they may come right into the target area unexpectedly. If this hack is used in the right place it would make for a great Halloween display item and could be used safely.

After the break you can watch [Rick’s] flame breathing Jack-o-Lantern build tutorial.

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Pseudo-Random Flickering Jack-O-Lantern LED Using ATtiny13

Pseudo_Random_Flicker_ATtiny13

It’s time to get those jack-o-lanterns twinkling for Halloween. If you don’t want to use candles or buy a jack-o-lantern light this Halloween you can do like [Johannes Bauer] and code your own pseudo-random flickering super bright LED. His wife wanted their pumpkin to be illuminated this year and he knew it would be easy to do with an Arduino, but that would be overkill for such a simple project. Plus, he doesn’t have an arduino. [Johannes] used very few components; 4 slightly depleted AA batteries, a super bright LED, 680 ohm resistor and a little custom code on an 8 pin ATtiny13. The circuit does work great for a pumpkin lantern but his video is more of a tutorial on coding linear congruential generator (LCG) for the 8 bit pseudo-random LED flickering.

The code is short and can be gleaned from the YouTube video. [Johannes] used avr-gcc to compile and has packaged his code and build scripts for download. The hex file can be flashed over to the chip using avrdude or AVR Studio. If you have any ATtiny13s lying around you should cobble this hack together just in time to emulate that real look of a pumpkin candle without the hassles and hazards of real flames.

If you want something with a lot more light that still has that candle like flicker then checkout “Flickering Pumpkin Lanterns” that used the signal from LED tea lights to power some 12 V lamps.

Follow along after the break to watch [Johannes Bauer’s] video.

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Halloween Knock Box

knock_box_top

[Kyle] has been an avid reader of HaD for a long time. In fact, he was inspired by a Halloween knock box from 4 years ago! He saved the link and finally this year, he went ahead and made his own.

So what is it anyway? Well, as the name implies, when you knock on it, it knocks back. And if you knock on it a special number of times, it’ll play a secret tune… It is a great little item to have at any Halloween event — and kids love it!

Design and function of the box is basically the same as the original, with a few modifications — most notably, swapping out the original PICAXE for an ATtiny85 microcontroller. [Kyle] even managed to find the lego skeleton and chains available on eBay. He’s put together a very thorough blog post on it and shared all the code and schematics — so if you’re looking for a last minute Halloween project, this might be it!

Stick around after the break to see the knocking in action!

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Alas, Poor Yorick! I Tweeted Him

yoreck the talking skull

You know Halloween is coming around when the tweet reading skulls start popping up. [Marc] wanted to bring the Halloween spirit into his workplace, so he built “Yorick”. In case you’re worried, no humans were harmed (or farmed for parts) in the creation of this hack. Yorick started life as an anatomical skull model, the type one might find in a school biology lab. Yorick’s skull provided a perfect enclosure for not one but two brains.

A Raspberry Pi handles his higher brain function. The Pi uses the Twitter API to scan for tweets to @wedurick. Once a tweet is found, it is sent to Google’s translate server. A somewhat well-known method of performing text to speech with Google translate is the next step. The procedure is simple: sending “http://translate.google.com/translate_tts?tl=en&q=hackaday” will return an MP3 file of the audio. To get a British accent, simply change to google.co.uk.

The Pi pipes the audio to a speaker, and to the analog input pin of an Arduino, which handles Yorick’s lower brain functions.  The Arduino polls the audio in a tight loop.  An average of the last 3 samples is computed and mapped to a servo position. This results in an amazingly realistic and automatic mouth movement. We think this is the best part of the hack.

It wouldn’t’ be fair for [Marc] to keep the fruits of his labors to himself, so Yorick now has his own Livestream channel. Click past the break to hear Yorick’s opinion on the Hack A Day comments section! Have we mentioned that we love pandering?

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Light Up Earrings

light up earrings

Unfortunately [ch00f’s] been too busy to write for Hack a Day lately, but he has finished off an awesome little project — Christmas LED earrings!

As with all his projects, there is a brilliant write up that covers everything — even for the stuff that didn’t work. But what we really have to admire about this project in particular is the scale at which he was working. The tiny battery squished in between the two boards? A mere 19mAh. Which is actually enough to power the earrings for a few hours, but is only the size and thickness of a few microSD cards!

The second thing that really popped out at us was the boards themselves, there’s just no room for a programming header! To work around this [ch00f] actually made the PCBs in 3 segments, programmed it, and then cut off the programming header section! If that’s not enough ingenuity, how about this – He also included hall effect sensors on-board to turn them off while charging! Not to mention an intricate wood box to charge them in…

Stick around after the break to see the great demo video, it even has some classy music from the 1930’s which really sets the mood.

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Halloween Doorknocker Decoration Hack

halloweenDoorHack

If you’re new to hacking, Halloween is a great excuse to get started, and [Chuck] has put together an inexpensive animated Halloween decoration that you can show off on your front door. After scoring a $5 plastic Halloween doorknocker from Wal-Mart, [Chuck] gathered together a small pile of components and then set about breathing some life (death?) into its scary but motionless face.

Though he opted to use a Digispark, you should be able to use any Arduino that is small enough to stuff inside the plastic head. [Chuck] cut some holes in the eyeballs and glued in two RGB LEDs, then cobbled together a quick-and-dirty mount in the mouth area to hold a small servo. The lights and the servo are wired to the Digispark, which turns the lights on and instructs the servo to slam the ring against the door. It’s is battery powered and currently has only two settings: on or off. This should be good enough to scare the kids for this year, but [Chuck] has plans to add a much-needed motion sensor and sound via a Bluetooth connection. 

As simple as this build is, it could be just the thing to get you in the holiday spirit, or to introduce the young hacker in your home to the world of electronics and coding. Check out the short video of the doorknocker after the break, then swing by [Chuck’s] website for detailed build instructions and his Github for the source code. If you’re having trouble finding this doorknocker at Wal-Mart, [Chuck] recommends a similar one on Amazon. Don’t stop now! Make some Flickering Pumpkins too, or if you want a challenge, hack together your very own Pepper’s Ghost illusion.

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Pepper’s Ghost – Halloween Ghosting

Peppers Ghost is a classic technique for making ghosts appear in pictures, video, and even in front of live audiences. In this week’s Halloween themed Instructable, learn how to recreate the effect at home.

It’s really quite simple. By positioning a clear piece of lexan at a 45 degree angle to your “ghost” object, and having the audience (or camera) looking at the lexan at the opposite 45 degree angle, you can produce a very simple ghost effect. This is a great trick for producing some scary ghosts in your haunted house.

But wait. Isn’t this a bit too simple? This is Hack a Day isn’t it? How about making a real moving hologram, isn’t that a bit more of our speed?

Well, this is the exact same technique that is used to make real holograms — just replace that object with a projected image or video! We’ve covered it a couple of times before, explaining the Tupac hologram, and showing off a cool leap motion controlled globe hologram.

Our challenge to you is to make a moving hologram Halloween decoration. After all, you can get pico projectors for less than $100 these days, so why not give it a try? There’s a few more ideas and techniques for positioning the lexan in the video after the break.

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