2023 Halloween Hackfest: Haunted Keyboard Is Free From Ghosting

This may look like another DIY mechanical keyboard, but it’s hiding a secret. [Mx. Jack Nelson] has combined Halloween and keyboards in glorious, haunted fashion. Type a line, any line into this bad boy and you get a spooky, sort of cryptic response generated by AI.

Essentially, a Raspberry Pi Pico W does all the work, it handles the keyboard matrix, connects to Wi-Fi, sends the input to ChatGPT, and spits the response out on the screen wherever the cursor happens to be. Incidentally, it turns out [Mx. Jack Nelson] used ChatGPT to generate much of the CircuitPython code.

The layout is a custom 40% that is heavily influenced by the Akko 40%, with the Ctrl, Alt, and Win keys replaced by Ctrl, Cmd, and Opt. This was [Mx. Jack Nelson]’s first PCB, and you never forget your first. You don’t want to miss the demo video after the break.

Are keyboards just not spooky enough for you? Here’s a creepy baby doll that does basically the same thing.

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2023 Halloween Hackfest: Candy Basket Sees You Coming

On Halloween, some people can’t or don’t want to open the door for various reasons. Maybe they have a cat that likes to escape every chance it gets, or maybe their favorite TV show is on during prime trick-or-treating time. Whatever the case, we think it’s perfectly acceptable to leave a bowl of candy outside the door, especially if there are electronics involved.

In this case, the bowl detects trick-or-treaters and candy eaters using an LD2410 60 GHz radar sensor and an RP2040. A light pipe shows orange when a person is detected, and switches over to green as they come closer, as if to say you may have candy now.

Nothing happens after that, but now that we think about it, it would be cool to add an MP3 decoder and a speaker to play a little witch cackle or something once they’ve had a chance to stick their hand in the bucket.

[Mike Kushnerik] actually designed the PCB a few months ago for non-Halloween purposes: some home automation projects. But then they were trying to think of something for Halloween, and this delightful light-up bucket came to mind. In addition to the RP2040 chip, there’s a 128 MB flash chip, a WS2812 LED, and a header for communicating with the radar sensor over UART. Be sure to check out the brief demo video after the break.

If you’d like to stand outside and give out candy, at least send it down a light-up slide or something.

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Hello, Halloween Hackfest!

Halloween is possibly the hackiest of holidays. Think about it: when else do you get to add animatronic eyes to everyday objects, or break out the CNC machine to cut into squashes? Labor day? Nope. Proximity-sensing jump-scare devices for Christmas? We think not. But for Halloween, you can let your imagination run wild!

Jump Scare Tombstone by [Mark]
We’re happy to announce that DigiKey and Arduino have teamed up for this year’s Hackaday Halloween Contest. Bring us your best costume, your scariest spook, your insane home decorations, your wildest pumpkin, or your most kid-pleasing feat!

We’ll be rewarding the top three with a $150 gift certificate courtesy of DigiKey, plus some Arduino Halloween treats if you use a product from the Arduino Pro line to make your hair-raising fantasy happen.

We’ve also got five honorable mention categories to inspire you to further feats of fancy.

  • Costume: Halloween is primarily about getting into outrageous costumes and scoring candy. We don’t want to see the candy.
  • Pumpkin: Pumpkin carving could be as simple as taking a knife to a gourd, but that’s not what we’re after. Show us the most insane carving method, or the pumpkin so loaded with electronics that it makes Akihabara look empty in comparison.
  • Kid-Pleaser: Because a costume that makes a kid smile is what Halloween is really all about. But games or elaborate candy dispensers, or anything else that helps the little ones have a good time is fair game here.
  • Hallowed Home: Do people come to your neighborhood just to see your haunted house? Do you spend more on light effects than on licorice? Then show us your masterpiece!
  • Spooky: If your halloween build is simply scary, it belongs here.

Head on over to Hackaday.io for the full details. And get working on your haunts, costumes, and Rube Goldberg treat dispensers today.

Spooky Noise Box Has Post-Halloween Potential

There’s more than one way to scare people on Halloween. Sure, there’s always the low-brow jump scare, but that will generally just annoy the person and possibly cause a heart attack. No, what you need is a sustained soundscape of hellish audio. And where does one find hellish audio? Well, you make your own with a spooky-sounds noise box.

And no, we’re not talking about a soundboard that goes ‘boo’ and ‘ooo-OOO-oooh’ and whatnot. This is a full-on DIY instrument that has potential beyond Halloween. Essentially, the wooden box takes input vibrations from various doodads, and these vibrations are picked up by a piezo disk or two glued to the underside of the lid. The piezos are wired up to a 3.5 mm jack, which runs out to the PC and [SvartalfarQc]’s favorite Digital Audio Workstation (DAW). From there, it’s just a matter of playing around with the sounds — looping them, running them through various instrument voices, adding effects, and so on.

We love the the things that [SvartalfarQc] came up with, including a wind-up walking heart thing, a retractable badge holder, and that noise box mainstay, a sproingy doorstop.

We all know piezos are awesome, but have you ever considered that they can be used to digitize old wax cylinder recordings?

Angry Robot Face Is Less Than Friendly

Sometimes you just need to create a creepy robot head and give it an intimidating personality. [Jens] has done just that, and ably so, with his latest eerie creation.

The robot face is introduced to us with a soundtrack befitting Stranger Things, or maybe Luke Million. The build was inspired by The Doorman, a creepy art piece with animatronic eyes. [Jens’] build started with a 3D model of a 3D mask, with the eyes and mouth modified to have rectangular cutouts for LED displays. The displays are run by a Raspberry Pi Pico, which generates a variety of eye and mouth animations. It uses a camera for face tracking, so the robot’s evil eyes seem to follow the viewer as they move around. In good form, the face has a simple switch—from good to evil, happy to angry. Or, as [Jens] designates the modes: “Fren” and “Not Fren.”

[Jens] does a great job explaining the build, and his acting at the end of the video is absolutely worth a chuckle. Given Halloween is around the corner, why not build five to eight of these, and hide them in your roommate’s bedroom?

Video after the break.
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Realistic Animatronic Eyes Are An Easy DIY Build

It’s not Halloween yet, but if you’re planning a technically-complicated costume, it might serve you well to start building now. To that end, here’s a guide from [Ikkalebob] on how to produce a compact animatronic eye mechanism.

The eye is inspired by mechanisms used in professional animatronics. However, that doesn’t mean it’s hard to build. Complex machining is done away with in favor of readily reproducible 3D-printed components. The eyes are able to look in different directions and can move realistically, and the build includes working eyelids that have a great blinking action to them that feels very natural. An Arduino Uno is charged with running the eyes, paired with a bunch of hobby servos and an Adafruit PCA9685 servo driver. A hefty 5V, 4 amp power supply is on hand to deliver enough juice so the servos move smoothly without stuttering.

It’s the kind of thing that’s perfect for your spooky familiar, or installing eyes in the back of your head. It would be perfect to hide behind a window or in the bushes, too. Video after the break.

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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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