Build Your Own Mini Fogging Cauldron

The best cauldrons are full of bubbling, steamy potions of great magical potential. We don’t have many of those in the real world, though, so sometimes we have to make do with a simulacra. [wannabemadsci] has built just that, with this fogging cauldron prop that uses no fog fluid or dry ice, running solely with water instead.

The heart of the build is a piezo element that vibrates at ultrasonic frequencies to atomize water. They’re available from websites like AliExpress complete with a driver circuit to energize the piezo element. The water is delivered from a wetted fiber wick, and quickly becomes a fog when the piezo is energized.

The disk was installed in a custom PVC water cup with the wetted wick, along with the electronics. The assembly was then lowered into an off-the-shelf plastic cauldron party favor to complete the look. The trick is to mount the piezo element sideways to get a nice-looking distribution of fog. A green LED was installed to light the cauldron from within.

The resulting effect is a sinister-looking glowing cauldron with a steady stream of fog emanating from the top. It’s a great piece of Halloween decor, and as a bonus, it doesn’t require any fancy chemicals to make it work. If you’re thirsty for more, be sure to check out the winners of last year’s Halloween Hackfest. Video after the break.

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Halloween Mirror Offers A Mighty Fright

Jump scares are controversial in the horror world, whether you’re talking about movies or video games. You can bring that same irritating thrill into real life, too, with this Halloween mirror from [jasonwinfieldnz].

During the day, or simply when it’s bright inside, the mirror appears normal, like any other. However, behind the special two-way mirrored glass surface is a spooky 3D print, such as a skull or an annoying yellow cartoon character. When the lighting level gets low, everything changes. A light-dependent resistor hooked up to a Digispark detects the change, and then fires up some 5V LEDs to light the scary image, revealing it behind the mirror. Even better, it plays a loud screaming sound with the help of a DFplayer MP3 module.

We’d love to see the concept taken even further, too. It would be quite something if, when a passer-by approached, the room lights suddenly cut out and the mirror activated in its full glory.

We’ve seen some great Halloween builds over the years. If you’re eager to get one out this season, you might wanna get hacking now! Video after the break.

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Creepy Halloween Doll Might Make You Betsy Wetsy

If you want to terrify your neighborhood this Halloween, you might go for the old standbys like skeletons or zombies. But you don’t have to go gory to find glory. Consider the talking doll. Those things are creepy enough already, right? Well, [cabuu] says no, the doll should be animated with servos and have remote control. She should still be able to talk, just not when you expect her to.

Forget pushing on her stomach, ’cause Baby’s got a Wemos D1 mini and her own Blynk app now.  A set of sliders in the app control a micro servo that animates her eyes, and another servo that twists her head from side to side. Her head doesn’t go all the way ’round, but that’s probably for the best. There are preset fright modes [cabuu] can set and forget until she springs to life via motion sensor.

We particularly like the bracket [cabuu] designed and printed that joins the eyeballs with the servo, along with his clever use of printed mate brackets to hold the servos in place within the head. If you think you can stomach it, there’s a demo video after the break. Stay tuned for total doll dissection after that as [cabuu] builds and inserts the terrifying tidbits.

We love hacks that combine innocence with insanity. Have you ever seen Thomas the Tank Engine singing Rick Astley?

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Sort Your Candy With A Raspberry Pi And Google Cloud Vision

If you have been off trick-or-treating and returned home with an embarassment of candy, what on earth can you do to mange the problem and sort it by brand?

Yes, it’s an issue that so many of us have had to face at this time of year. So much a challenge, that the folks at [Dexter Industries] have made a robotic candy-sorter to automate the task.

OK, there’s something of the tongue-in-cheek about the application. But the technology they’ve used is interesting, and worth a second look. Hardware wise it’s a Lego Mindstorms conveyor and hopper controlled by a Raspberry Pi through the BrickPi interface. All very well, but it’s in the software that the interest lies. They use the Raspberry Pi’s camera to take a picture to send off to Google Cloud Vision, which they then query to return a guess at the brand of the candy in question. The value returned is then compared to a list of brands to keep or donate to another family member, and the hopper tips the bar into the respective pile.  They provide full build details and code, as well as the video we’ve put below the break. So simple a child can explain it, sort of.

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BOO! Teach Arduino Basics With This Fun Ghost

Halloween is just around the corner, and the spooky themed tips are just starting to roll in. If you’re looking to one-up the basic store-bought decorations, and maybe teach your kid the basics of an Arduino while you’re at it — why not build a Peek-A-Boo Ghost!

Using an Arduino, two servo motors and an ultrasonic distance sensor it’s pretty easy to make this cute little ghost that covers its eyes when no one is around. They’re using cardboard for the ghost, but if you have access to a laser cutter at your hackerspace, you could make it a lot more robust using MDF or plywood.

When the ultrasonic distance sensor senses someone coming towards it, it’ll trigger the arms to move — though it’d be easy to add a small speaker element too and get some spooky music going as well!

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"Stomach Shot" lets you see through your zombie corpse.

“Stomach Shot” Halloween Costume

Halloween may have come and gone, but [Luis] sent us this build that you’ll want to check out. An avid Walking Dead fan, he put in some serious effort to an otherwise simple bloody t-shirt and created this see-through “stomach shot” gunshot wound.

The project uses a Raspi running the Pi Camera script to feed video from a webcam on the back of his costume to a 7″ screen on the front. [Luis] attached the screen to a GoPro chest harness—they look a bit like suspenders—to keep it centered, then built up a layer of latex around the display to hide the hard edges and make it more wound-like. Power comes from a 7.4V hobby Lipo battery plugged into a 5V voltage converter.

After ripping a small hole in the back of his t-shirt for the webcam and a large hole in the front for the screen, [Luis] applied the necessary liberal amount of fake blood to finish this clever shotgun blast effect.

Halloween Hack Night At Pololu

Have some servos and an Arduino lying around? It isn’t too late to get your freaky on! Last night, tech enthusiasts of Las Vegas gathered at Pololu Robotics to show off their hacks for a Halloween flavored edition of their bi-monthly robot club. These projects created by those in the community as well as the Pololu engineers themselves are fun and have a relatively short list of materials. So, if the examples below give you some inspiration, this is permission to Macgyver something together before your big Halloween party tonight…

roboFingersImpatient Severed Fingers – [Amanda] came up with a cute use for some mini servos and a zombie hand prop. The five severed fingers were attached to one end of a plastic rod. The other end was mounted to each of five servos which were laid out in the appropriate hand shape and attached to a fixed base. An Arduino running a basic sweep sketch animated the motors at slightly staggered intervals, creating a nice rolling effect. Even with the moving parts exposed this prop would be awesome to have on display, or set the ambiance with its continuous tapping…

deltaSpectorAngry Spectral Delta – [Nathan Bryant] made an actual costume for his delta robot from Robot Army. By attaching a small plastic skull to the end effector and draping a tattered piece of fabric over the rest of the mechanism he effectively transformed the delta into a little ghost with a sassy personality. The head swiftly bobbed about, all while staying parallel to the table… until it intermittently came unhinged and hung limply, which was a nice added effect!

 

exorcismBabyRobotic Exorcism Baby – This doll could turn its half skeleton, half baby face 180 degrees and then laugh at your fear. By attaching two servo motors together, [Jeremy] was able to create a pan and tilt mechanism which acted as the baby’s contorting neck and chattering jaw. The micro controller sending commands to the motors was hidden modestly under her dress.

 

shadowBoxStabby Animated Cardboard Shadowbox – Among the animatronic devices seen at the event was a shadowbox made by [Brandon] hidden in a dark conference room nearby. When one happened to walk past the seemingly unoccupied space, they’d glimpse the silhouette of an arm stabbing downward with a knife through a windowsill. Being lured in for further investigation you’d find that the shadow was being cast by some colored LEDs through a charmingly simple device. A cutout made from recycled card stock was attached to a single servo. This whole mechanism itself rocked back and forth slightly as the motor moved, which wasn’t intentional but added some realism to the motion of the stabby arm.

There were many interesting projects present last night ranging from remote-controlled skeletal arms to other reactive devices ready to deliver a scare. If you’re interested in knowing more, those made by the Pololu crew are documented on their blog. Since video does these projects better justice, you can check out a compilation of clips here:

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