Is It Finally Time For Christmas Decorations?

December 3, 2021 by Orlando Hoilett 14 Comments

[Arnov] is trying to get into the holiday spirit and is doing so the way he knows how. He was thinking of some cool decorations for his Christmas tree and decided the best decorations are the ones you make yourself, so he made his own blinky Christmas tree ornament.

The famed “blinky circuit” is certainly one that we are no strangers to here at Hackaday. Some of our readers will be very pleased to see that he did in fact use a 555 timer and not an Arduino. The 555 timer is wired to drive the clock pin of the CD4017 decade counter and the outputs of the decade counter are wired to the LEDs. The LEDs are lit up sequentially upon each low to high transition of the clock pulse though you may try getting creative with your LED wiring scheme to achieve different blinking effects.

What readers might really take away from this build is [Arnov] detailing how to import images into his CAD tool of choice, OrCAD in his case. We know that can be a bit tricky sometimes. Finally, we love that this project doubles as PCB art and a soldering challenge. It would definitely make for a good demo project at your next beginner soldering workshop.

Cool project [Arnov!]

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Why Deep Frying Turkey Can Go Very Wrong

November 24, 2021 by Lewin Day 93 Comments

Tomorrow is Thanksgiving and that means Americans across the United States will be cooking up a turkey feast. One of the most popular ways to cook the bird is by deep frying it in oil.

Local TV stations everywhere spend this week warning about turkey frying. They’re not wrong… if things get out of hand you can end up burning down your house, if not your entire street. Let’s talk the science behind November turkey fires, and hopefully avoid a turkeyferno.

Simple Errors

The typical setup for deep frying a turkey involves lowering the bird into a big pot full of oil sitting on a gas burner. Ropes and pulleys are often used to lower the turkey into the pot to avoid getting one’s hands near the hot oil. Ideally, this should be done in a backyard, away from structures, to provide good ventilation and plenty of room in the case something does go wrong.

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showing the ramp and sprayer of the cider press

The Spiced (Cider) Must Flow

November 12, 2021 by Matthew Carlson 18 Comments

A fresh-squeezed glass of orange juice with breakfast seems like a trope that’s straight from a late 1980s sitcom. Making orange juice is easy; press until the liquid comes out. Apple juice (and, by extension, apple cider) is the same principle but requires much more force to squeeze out the juice. So what if you, like [Peter], have 900 lbs (408.2 kg for those metrically minded) of apples that you want to make cider out of? The obvious solution is to create a somewhat automated homemade cider press with lasers.

An earlier effort to make 25 gallons of cider took several full days of struggle for four people, so [Peter] knew he had to plan better next year. [Peter’s wife] milled and glued red oak into a large, sturdy frame that could press down with proper force and not break. [Peter] reached out to the local metal shop to fabricate a stainless steel tray with a custom drain. The cider basket itself and the pressboard were maple with waterproofing oil.

However, just because you can press apples, doesn’t mean you’re ready to make cider. They still need to be washed, cut, and ground into a pulp. A ramp was fashioned that it could be set in a truck bed with sprayers to wash the apples as they rolled by. A laser circuit with an LM393 opamp and a photoresistor allowed the sprayers to only activate when there was actually an apple to spray. Apple grinders are tricky as they need to survive the drop of several one-pound balls while staying at a reasonable speed. The grinder dispenses the pulp into a mesh nylon bag in a 5-gallon bucket, ready to be pressed. For the curious reader, 900lbs of apples yielded 60 gallons of delicious cider.

If you’re looking for a smaller scale press, here’s a cider press that’s a little simpler to make.

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.

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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!

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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.

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