Fire Breathing Jack-O-Lantern of Death

fire_pumpkin

[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.

[Read more...]

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.

[Read more...]

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!

[Read more...]

DIY Pneumatic Skeleton and Air Horn Gag to Scare Those Trick-Or-Treaters

Horn_Skeleton_Gags

[Rick Osgood] has been busy making more scaring gags for Halloween. This week he’s sharing great ideas for an air horn and pneumatic jumping skeleton, both actuated by 24 V sprinkler valves. These two new gags can easily be activated using [Rick’s] cardboard floor plate switch and three 9 V batteries cleverly snapped together in series for a 27 V supply (we can’t resist dropping in this link to a 2196 V supply from 9 V batteries just for fun).

The air horn construction is quite unique using a latex balloon strategically located as a reed valve for the air to vibrate over as it rushes out making a very loud honking sound. [Rick] then connected his manual bicycle pump to an air supply so that when an air valve is actuated the bicycle pump handle with a skeleton wired to it pops up. It then lowers back down via a bleed hole in the air line. Both the air horn and pneumatic pop-up skeleton seem simple to construct and his tests show them functioning perfectly.

Being the air storage chambers are small the re-trigger setup seems too repetitive to be practical for a continuous stream of Trick-Or-Treaters. Perhaps one could hide an air compressor with a long feed line to supply the gags? Plus, using an air compressor would come in handy for other scary blasts of air. Of course you would want to lower the compressor’s output regulator to safe levels so you don’t risk blowing apart your pop-up skeleton rig or any pipes.

Follow along after the break to see how to build these two great gags and get some tips from Mr. Safety.

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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.

[Read more...]

DIY Pressure Plate Switch for your Haunted House

Pressure Plate

Yes, its Halloween time again and the hacks are going to be crawling out of the woodwork for the rest of the month. [Rich Osgood] is off to a good start promising one hack every week until Halloween. Judging from this first project, a DIY pressure plate switch, we think there’s going to be a common theme to follow. [Rich] constructs his pressure plate for almost no cost using cardboard, tinfoil and duct tape. It couldn’t be easier, so make lots of these if your haunting project requires pressure plate triggers to activate any spooks. Judging by the cardboard construction it’s likely they will fail after multiple uses, but you can switch one out quickly requiring only two hookup wires and a bit of tape.

Hopefully we aren’t stealing [Rich’s] thunder by recommending using Xbee wireless remote sensors to covertly monitor guests or trigger spooktacular scares.

We will be keeping an eye out for [Rich's] follow-up Halloween hacks. Join us after the break to watch the tutorial video on making homemade pressure plates.

[Read more...]

LEDs turn the heat up on flameless pumpkin lights

led-peter

When tea lights just won’t do, why not move up to a 5 channel LED candle simulator?

Halloween is fast approaching. Peter’s local hackerspace, The Rabbit Hole had a meeting to carve pumpkins and talk Halloween hacks. After seeing how poorly a tea light illuminated a medium size pumpkin, this hack was born. We’ve seen LED jack-o’-lantern hacks before, but this one was worth a second look.

In true hackerspace style, [Peter] used what was available to him. A PIC12F508 is the heart of the project. The 12X508/9 series has been around for at many years, and is still a great chip to work with. We remember using the ‘C’ version of this chip to bypass region locks on original PlayStation systems. [Peter] created a simple circuit with two basic modes. In “value mode” the 508 drives LED’s directly from its I/O pins. This limits the total output to 60mA. In “premium mode”, some 2N3904 NPN transistors are brought in to handle the current.  This allows the PIC to drive up to 5 LEDs.

Candles can be tricky to simulate with LEDs. [Peter] used 5 independent 16 bit linear feedback shift registers to generate pseudo random bit streams. The effect is quite impressive. A “wind simulation” completes the illusion of a real flame. [Read more...]

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