Halloween Pumpkin Scares With An Evil Eye

These days, a classic Jack O’ Lantern just doesn’t cut the mustard. Kids are expecting to be scared by high-quality animatronics at a minimum. This haunting work by [Zero To Infinity] might just do the trick.

A real pumpkin is pressed into service in this build, with the usual threatening grin and candlelit interior. However, where it differs is in its single, animated eye. The eye itself is constructed of a pingpong ball, drawn upon with markers for a creepy bloodshot look. A pair of servos allow the eye to twitch and roll, under the command of an Arduino Nano. For further interactivity, an ultrasonic sensor is used to only trigger the pumpkin when it senses a person approaching.

It’s a fun holiday build that also serves as a great primer on how to work with servos and microcontrollers. We can imagine a more advanced setup using more sensors and pumpkins to train multiple eyes on the unsuspecting visitor. If that’s not scary enough, perhaps just make your pumpkins breathe fire instead. Video after the break.

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Haunted TV Does Mirror Scares With Raspberry Pi

Hallowe’en may be over for another year, but that just means you’ve got more time to prepare your build for next time. [gocivici] has a fun twist on the classic mirror scare that might be just up your alley.

The build starts with an old black and white TV, hooked up to a Raspberry Pi 3. The Pi films the scene in front of the television through a camera secreted into the screen’s headphone jack, and displays it on screen. The camera feed is run through OpenCV, which runs face and eye detection algorithms to determine when a person is looking at the screen. Based on a basic timer script, when a viewer has looked long enough, a ghostly apparition is displayed, lurking behind the viewer. When the user looks over their shoulder, the apparition quickly disappears, as per the classical horror trope.

It’s a fun build that would make an excellent set piece for your next Hallowe’en party. For extra effect, be sure to secret it down a dark hallway with some IR LEDs illuminating the scene for the camera only. If you prefer something with a little more whimsy, consider these animated singing pumpkins instead. Video after the break.

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Raspberry Raven Pi Security Camera Does Double Duty

The worst thing about holiday decorations is that while you could leave them up all year, your neighbors probably won’t like you very much for it. Christmas lights on your house are one thing, but as far as Halloween decorations go, [MisterM]’s raven security camera is one of the few exceptions to this rule.

Nevermore will [MisterM] wonder who goes there. As soon as this raven lays its beady red LED eyes on whatever is lurking in the garden, it comes to life with a bit of head swiveling and some random sounds. The bird either goes CAW! or quotes Christopher Lee’s reading of Edgar Allen Poe’s “The Raven”.

Inside this bird’s chest cavity is a Raspberry Pi 2 and standard camera, a servo to swivel the head, and an audio amplifier and speaker. This bird is running MotionEye on top of the Raspi OS so it can run a script whenever it senses motion.

We like that [MisterM] was able to find right-sized bits of plastic to mount the servo in the neck and the horn to the head. It just goes to show that not everything needs a 3D printer, a CNC, or woodworking. Check out the scary demo after the break.

Want to scare the whole neighborhood? Check out the science behind good-looking house projections.

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Hackaday Links: November 1, 2020

We normally chuckle at high-profile auctions where people compete to pay as much as possible for items they clearly don’t need. It’s easy to laugh when the items on the block are things like paint-spattered canvases, but every once in a while some genuine bit of history that really piques our interest goes on sale. Such is the case with what is claimed to be an original Steve Wozniak-built Blue Box, going on sale November 5. The prospectus has an excellent summary of the history of the “Two Steves” and their early business venture making and selling these devices to Berkeley students eager to make free long distance phone calls. The item on sale is a very early rev, most likely assembled by Woz himself. The current owner claims to have bought it from Woz himself in the summer of 1972 while on a roadtrip from Sunnyvale to Los Angeles. Estimated to go for $4,000 to $6,000, we really hope this ends up in a museum somewhere — while we’ve seen attempts to recreate Woz’s Blue Box on Hackaday.io, letting a museum study an original would be a great glimpse into our shared technological history.

Not in the market for old tech? No problem — Digilent wants to get rid of 3,000 PCBs, and quickly. They posted the unusual offer on reddit a couple of days ago; it seems they have a huge stock of populated boards for a product that didn’t quite take the market by storm. Their intention is likely not to flood the market with scopes cobbled together from these boards, but rather to make them available to someone doing some kind of art installation or for educational purposes. It’s a nice gesture, and a decent attempt to keep these out of the e-waste stream, so check it out if you have a need.

Speaking of PCBs, SparkFun has just launched an interesting new service: SparkFun À La Carte. The idea is to make it really easy to design and build prototype boards. Instead of using traditional EDA software, users select different blocks from a menu. Select your processor, add components like displays and sensors, and figure out how you want to power it, and SparkFun will do the rest, delivering a fully assembled board in a few weeks. It certainly stands to suck the fun out of the design process while also hoovering up your pocketbook: “A $949 design fee will be applied to all initial orders of a design”. You can get your hands on the design files, but that comes with an extra fee: “they can be purchased separately for $150 by filling out this form”. But for someone who just needs to hammer out a quick design and get on with the next job, this could be a valuable tool.

Another day, another IoT ghost: Reciva Radio is shutting down its internet radio service. A large banner at the top of the page warns that the “website will be withdrawn” on January 31, 2021, but functionality on the site already appears limited. Users of the service are also reporting that their Reciva-compatible radios are refusing to stream content, apparently because they can’t download anything from the service’s back end. This probably doesn’t have a huge impact — I’d never heard of Reciva before — but it makes me look at the Squeezebox radio we’ve got in the kitchen and wonder how long for the world that thing is. It’s not all bad news, though — owners of the bricked radios will now have a great opportunity to hack them back into usefulness.

By the time this article is published, Halloween will be history and the hordes of cosplaying candy-grubbers who served as welcome if ironic respite from this non-stop horror show of a year will be gone. Luckily, though, if it should come to pass that the dead rise from their graves — it’s still 2020, after all — we’ll know exactly how to defeat them with this zombie invasion calculator. You may remember that last year Dominik Czernia did something similar, albeit with vampires. Switching things up from the hemophagic to the cerebrophagic this year, his calculator lets you model different parameters, like undead conversion percentage, zombie demographics, and attack speed. You’ve also got tools for modeling the response of the living to the outbreak, to see how best to fight back. Spoiler alert: everyone will need to bring Tallahassee-level badassery if we’re going to get through this.

Animated Pumpkins Sing And Scare On Halloween

The animated video combined with the 3D-printed prop makes for an excellent effect.

Carving Jack O’ Lanterns out of pumpkins is a favorite Hallowe’en tradition for many, but relying on candles and knives is decidedly low-tech. [Lewis] of [DIY Machines] decided to whip up something a little more animated to scare the local trick-or-treaters instead.

The build consists of 3D printed pumpkins, lit from behind with a low-cost projector. Driven by a Raspberry Pi, the projector plays video files that project animated faces onto the pumpkins. The effect is great, giving the illusion of a real anthropomorphic Jack O’ Lantern sitting on your very porch. To control the system, a series of arcade buttons are hooked up to the Raspberry Pi allowing visitors to activate a song, a scare, or a story.

It’s a fun build that is a great way to add some interactivity to your Hallowe’en decorations. If you want to take your work up a notch, consider projecting on to your whole house. Video after the break.

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Five-Axis Pumpkin Carving

The day of carved pumpkins is near, and instead of doing manually like a mere mortal, [Shane] of [Stuff Made Here] built a five-axis CNC machine to take over carving duties. (Video, embedded below.)

[Shane] initially intended to modify his barber robot, but ended up with a complete redesign, reusing only the electronics and the large ring bearing in the base. The swiveling spindle is a rotating gantry with two sets of aluminum extrusions for vertical and horizontal motion. The gantry isn’t very rigid, but it’s good enough for pumpkin carving. Software is the most challenging part of the endeavor due to the complexity of five-axis motion and mapping 2D images onto a roughly spherical surface. Cartographers have dealt with this for a long time, so [Shane] turned to Mercator projection to solve the problem. We’re also relieved to hear that we aren’t the only ones who sometimes struggle with equation-heavy Wikipedia pages.

Since there are no perfectly spherical pumpkins, [Shane] wrote a script to probe the surface of the pumpkin with a microswitch before cutting, appropriately named “TSA.exe”. The machine is capable of carving both profiles and variable depth lithophanes, mostly of [Shane]’s long-suffering wife. She seriously deserves an award for holding onto her sense of humor.

With projects like explosive baseball bats and CNC basketball hoop, the [Stuff Made Here] YouTube Channel is worth keeping an eye on.

Projecting Halloween Peril

Every holiday has a few, dedicated individuals committed to “going all out.” Whether they’re trying to show up the neighbors, love the look, or just want to put a smile on the faces of those passing by; the results are often spectacular. A recent trend in decorations has been away from analog lights and ornaments and towards digital light shows via a projector. [Georgia Clegg] and [Luma Bakery] have written up a fantastic guide detailing the involved process of house projection for those feeling the holiday spirit.

There is more to the effect than simply pointing a projector at a home and running a video clip. The good displays make use of the geometry of the home and the various depths of the walls don’t distort the picture. The house itself is mapped into the image being displayed.

There are generally two approaches to mapping: point of view mapping and neutral/orthographic mapping. The first is just setting the projector in a fixed position and designing the graphics in such a way that they will look correct. The downside is that if there are multiple projectors, each projector will need to be separately designed for and they cannot be moved or adjusted. The second maps the house in an actual 3d sense and figures out how to display the content according to the viewpoint that the projector is currently at. This means you can create one source content and simply export it for the various projectors.

As you can imagine, the second is much more involved and this is where [Georgia Clegg] has stepped in. There’s a whole series that covers creating your house in MeshRoom, cleaning it up in Blender, creating the videos in After Effects, and setting up your projector to keep it running through the season.

We’ve seen other amazing projector mapping displays with lasers here at Hackaday. Now you can make one yourself. Just don’t get bogged down refurbishing your vector projector along the way.
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