Build This Halloween-Themed TensEGGrity Sculpture

October 21, 2022 by Lewin Day 5 Comments

Tensegrity sculptures are fun things, and often sold as office desk toys or scientific novelties. You can build your own too, and [seabirdhh] has whipped up a fun holiday-themed version.

The first part to build is the egg-hat-stand. This consists of the base of the structure, with the “hat” of the egg character hanging in the center. The other half of the structure is built separately, with the rest of the “egg head” sitting in a cup in the bottom of the upper structure. A series of nylon threads are then tied between the components. These can then be tensioned to give the structure its shape, allowing the egg’s “hat” to hover above its “head”. [seabirdhh] passes the nylon threads through small pieces of rubber that allow the tension to be adjusted just right. Too little and the structure falls down, but too much, and it will bend over time. Tuning it carefully is key.

It’s a fun build, and a cheap way to experiment with tensegrity concepts at home. You can even use these same techniques to build a quadcopter, or apply them in the world of LEGO. Video after the break.

Continue reading “Build This Halloween-Themed TensEGGrity Sculpture” →

Halloween Mirror Offers A Mighty Fright

August 16, 2022 by Lewin Day 22 Comments

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.

Continue reading “Halloween Mirror Offers A Mighty Fright” →

Children playing a zombie shooting game on a big screen

Halloween Game Lets You Shoot Zombies With A Laser-Powered Crossbow

November 12, 2021 by Robin Kearey 1 Comment

Suppose you were looking for all the essential elements to make a great Halloween-themed shooting game. Zombies? Check. Giant “lasers”? Check. Crossbows shooting forks? We’ve got you covered. Check out “Fork The Zombies“, which was set up by [piles.of.spam] to entertain the neighborhood kids this Halloween.

The game is played on a big screen, which shows a horde of angry zombies marching toward the player, who has to shoot as many as possible before they reach the front of the screen. The weapon provided is a crossbow; when the trigger is pulled, a fork is launched and hopefully skewers one of the ghouls. The game was written using an open-source engine called Urho3D, which takes care of all the hard-core 3D and physics work, allowing the user to focus on designing the gameplay and visuals.

To give the game a bit more of a physical feel, [piles.of.spam] made an actual crossbow for the player to wield. Its handle was cut from a scrap piece of wood, using a band saw for the general shape and a CNC machine for the delicate cut-outs that hold a laser pointer, an ESP32 and a microswitch-based trigger. The laser shines onto the game screen, while the ESP32 sends out a data packet over WiFi when the trigger is pulled.

The location of the shot is tracked using a clever trick: a webcam is pointed at the screen, with a red color filter in front. This way, it only sees the red laser dot moving across the screen. The resulting image is processed using the Python OpenCV library, which provides functions to convert the relative motion of the pointer on the screen to an absolute position along the playing field.

The computing hardware consists of a pair of Jetson Nano boards, which sport quad-core ARM A57 CPUs as well as powerful graphics hardware to generate the game’s visuals. The end result is impressive, especially given the fact that all of this was designed and built in just three weeks. It was apparently a great hit with its intended audience, as visitors queued to try their hand at shooting the hungry zombies.

Laser pointers are an obvious tool for creating shooting games: we’ve seen ones with a single round target, a set of shapes set up around you, and even metal cans that fall over and stand up again. But if you need to protect yourself in case of an actual zombie apocalypse, a slingshot that shoots knives might be more useful.

Continue reading “Halloween Game Lets You Shoot Zombies With A Laser-Powered Crossbow” →

Halloween Hack Requires Minimum Code, Produces Maximum Fun

November 7, 2021 by Adam Zeloof 11 Comments

Every year, [Conor O’Neill] hacks something together to spook and entertain trick-or-treaters who happen by his home on Halloween. He’s noticed a pattern — every year the project involves a mess of code, often slapped together using different frameworks and languages. Attempting to alleviate that, and maybe make things a bit more friendly to beginners who understandably find code-intensive project daunting, this year he set out to write as little code as possible.

Rather than take the electronics-only route, which would undoubtedly include a few 555 timers and some other classics, [Conor] elected to stick with higher-level embedded boards, including fan-favorites such as an ESP32 and a Raspberry Pi, while still trying to keep code to a minimum. Thanks to the visual languages Espruino Blockly and NODE-RED, he only needed to write a couple lines of “traditional code,” as he calls it: a simple JavaScript HTTP request. The project itself consisted of an ultrasonic sensor hooked up to an ESP32, which would detect when children approached the door. The ESP32 used Espruino visual scripting to notify a Raspberry Pi when it sensed motion. The Raspberry Pi would play some spooky sounds, and coordinate with some old conference badges to turn on some lights and trigger a fog machine. The Pi also used a service called Tines to send a door notification via Telegram.

Okay, so this is still by no means simple, but it is interesting how much can be done without writing much code (and the end result was great!). [Conor] says he’s been building similar Halloween projects every year for the last ten or so, and it shows — we wrote about another one of his haunted doorbells back in 2015. We’re looking forward to seeing what he cooks up next year, and we hope you’ll have some awesome automated Halloween decorations as well!

Continue reading “Halloween Hack Requires Minimum Code, Produces Maximum Fun” →

Spooky Winners Of The Halloween Hackfest Contest

November 4, 2021 by Kristina Panos No comments

It was a tight race, but the results of the Halloween Hackfest contest are in. We asked you to scare up a terrifying build in one of three categories, and as usual, you didn’t disappoint! These three hackers have each won a $150 shopping spree at Digi-Key to fund their future frights.

Best Undead Tech: 3-Axis Skull Mod for a 12-Foot Skeleton

Nelson Bairos

[Nelson] has been in the Halloween-based animatronics business for more than a decade, but always gets beaten to the punch when it comes to doing the really fun stuff like making things move and speak. Once [Nelson] got their hands on a 12-foot skeleton from the big box hardware store, it was time for the gloves to come off and the fun to begin.

The three axes of movement come from a rotation servo, a tilt servo, and a nod servo, all of which are connected to each other and the skeleton with 3D-printed supports. Lucky for us, [Nelson] documented this first build quite nicely and provided the 3D models, should you suddenly get the urge to go see if they have any of these magnificent skeletons left on clearance.

Best Haunted Smart House: Safety Coffin Grave Bell

Glen Atkins

What’s scarier than the undead? How about people who were buried alive, whether accidentally or not. Can you imagine hanging around in a graveyard, innocently doing tombstone rubbings or some ritualistic sacrifice when suddenly you hear someone ringing a bell and/or a terrified, muddled voice screaming for help?

[Glen Atkins]’ Safety Coffin Grave Bell build forgoes the body part, but in the dark, it’s easy to let your imagination run wild. It looks like a bell on a post, but pass too close and the ultrasonic rangefinder detects unsuspecting trick-or-treaters and gives them a scare by frantically ringing the bell with a big servo hidden inside. We hope they brought spare underwear.

Best Crazy Costume: Computer Head

Skye Rutan-bedard

[Skye] won a lot of people over last year with their computer head costume that featured a lone blinking eye and a voice. What those people didn’t know was that it suffered from three big problems: it had poor ergonomics from a heavy monitor shell, the blinkenlights matrix used to display emotions was underutilized, and using a keyboard proved to be an inconvenient UI for running the voice. This year, [Skye] set out to fix all the problems and make the costume even more awesome and comfortable to wear.

The brain of this computer head costume is a Raspberry Pi 4. As for [Skye]’s actual head, it is safely enclosed inside a hard hat that’s epoxied to the inside of the case. A wide range of emotions dance across the 16×16 RGB LED matrix that looks great behind some mirrored film, and they go great with the new voice method — [Skye] speaks softly into a small microphone, and the Raspi uses Mozilla’s DeepSpeech to repeat whatever they say in a robotic British accent.

Hack-y Halloween

Congratulations to all the winners, and a big thank you to all 45 entrants for your hair-raising hacks. Thank you also to Adafruit and Digi-Key for sponsoring this contest. We hope you had a great Halloween!

Skeleton Watches You Intensely Because It’s Halloween, Okay

October 30, 2021 by Lewin Day 1 Comment

If you’ve ever seen a painting in which the eyes follow you around the room, you might have found that a bit uneasy. [CuriousInventor] has taken that concept further with a skeleton that literally holds a gaze on anyone in its field of view.

The heart of the system is a Raspberry Pi Zero, fitted with a Pi Camera. Running OpenCV, code is set up to track humans and turn the skeleton’s head to face any that are detected. This is achieved via a servo in the skeleton’s neck. A servo bonnet is used to drive the servos without unnecessarily straining the Raspberry Pi.

The skeleton itself doesn’t look modified in any way, though most of the electronics are mounted inside a pretty obvious plastic box. We’d love to see a version 2 with all the hardware housed neatly inside the skull.

It’s a fun hack that makes for an enjoyable Halloween decoration. OpenCV can do other useful things, too, however, like spotting weeds. Video after the break.

Continue reading “Skeleton Watches You Intensely Because It’s Halloween, Okay” →

Halloween-Themed Talking Clock Relies On Pi Pico

October 27, 2021 by Lewin Day 3 Comments

Many of us learn to read clocks at a young age, however, talking clocks eliminate the need to do that entirely. [Alberto] whipped up one of his own, in this case designed with some Halloween holiday spookiness.

A basic clock movement is used to display the time in the typical fashion. However, the movement also features a built-in trigger signal, which it sends to an attached microcontroller on the hour, every hour. The build relies on the Raspberry Pi Pico for sound, chosen for its USB programming interface and its 2 MB of onboard flash storage. Sound is stored in simple 16-bit WAV files, and played out to a speaker via a PWM output. Alternatively, a CircuitPython version of the code is available that uses MP3s instead. A light sensor is used to avoid triggering any sounds at night time that could disturb one’s sleep. The entire circuit can be built on a single-sided board. [Alberto] etched one at home in the old-fashioned way, though one could also order one online, too.

Halloween is an excellent time for hacks, and this year we have the Halloween Hackfest contest to show them off. It’s ending soon though, you have until the stroke of midnight Pacific time on Friday (that’s the moment Thursday night ends) to enter your Halloween-themed hacks.

Talking clocks have been around for some time, but are nevertheless a fun and educational project to build. We’ve seen some other great Halloween hacks lately, too. If you’ve been busy with projects this fall holiday, don’t hesitate to drop us a line!