Optical illusion gingerbread house from an odd perspective

An Engineer’s Perspective On Baking Gingerbread Houses

If you’ve ever wanted to merge the worlds of holiday cheer and clever geometry, [Kris Wilk]’s gingerbread house hack is your ultimate inspiration. Shared in a mesmerising video, [Wilk] showcases his 2024 entry for his neighborhood’s gingerbread house contest. Designed in FreeCAD and baked to perfection, this is no ordinary holiday treat. His pièce de résistance was a brilliant trompe l’oeil effect, visible only from one carefully calculated angle. Skip to the last twenty seconds of the video to wrap your head around how it actually looks.

[Wilk] used FreeCAD’s hidden true perspective projection function—a rarity in CAD software. This feature allowed him to calculate the perfect forced perspective, essential for crafting the optical illusion. The supporting structures were printed on a Prusa MK4, while the gingerbread itself was baked at home. Precision photography captured the final reveal, adding a professional touch to this homemade masterpiece. [Wilk]’s meticulous process highlights how accessible tools and a sprinkle of curiosity can push creative boundaries.

For those itching to experiment with optical illusions, this bakery battle is only the beginning. Why not build a similar one inside out? Or construct a gingerbread man in the same way? Fire up the oven, bend your mind, and challenge your CAD skills!

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Antenna Hidden In Holiday Lights Skirts HOA Rules

For all their supposed benefits, homeowner’s associations (HOAs) have a reputation of quickly turning otherwise quaint neighborhoods into a sort of Stanford prison experiment, as those who get even the slightest amount of power often abuse it. Arbitrary rules and enforcement abound about house color, landscaping, parking, and if you’ve ever operated a radio, antennas. While the FCC (at least as far as the US is concerned) does say that HOAs aren’t permitted to restrict the use of antennas, if you don’t want to get on anyone’s bad side you’ll want to put up an antenna like this one which is disguised as a set of HOA-friendly holiday lights.

For this build, a long wire is hidden along with a strand of otherwise plain-looking lights. While this might seem straightforward at first, there are a few things that need to be changed on the lighting string in order to make both the antenna and the disguise work. First, the leads on each bulb were removed to to prevent any coupling from the antenna into the lighting string. Clipping the leads turns what is essentially a long wire that might resonate with the antenna’s frequency into many short sections of wire which won’t have this problem. This also solves the problem of accidentally illuminating any bulbs when transmitting, as the RF energy from the antenna could otherwise transfer into the lighting string and draw attention from the aforementioned HOA.

Tests of this antenna seemed to show surprising promise while it was on the ground, but when the string and antenna was attached to the roof fascia the performance dropped slightly, presumably because of either the metal drip edge or the gutters. Still, the antenna’s creator [Bob] aka [HOA Ham] had excellent success with this, making clear contacts with other ham radio operators hundreds of miles away. We’ve shared another of [Bob]’s HOA-friendly builds below as well which hides the HF antenna in the roof’s ridge vent, and if you’re looking for other interesting antenna builds take a look at this one which uses a unique transformer to get wide-band performance out of an otherwise short HF antenna.

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Spooky Coffin Bell Spooks Passers By On Halloween

Being buried alive isn’t fun, we imagine. Fear of it led to the development of various safety coffin ideas in the 18th and 19th centuries, and [Glen Akins] wonderful Halloween prop riffs on that tradition today. 

The safety coffin was a simple solution for those afraid that this might happen to them. One concept had a bell which was installed above freshly dug graves with a string extending into the coffin. One who found themselves accidentally buried alive could then pull the string to ring the bell and summon help.

[Glen’s] installation eliminates the coffin and the dead body, and simply mounts a bell on a post. Inside, there’s an ultrasonic rangefinder that detects passers by. When someone walks closely enough to the prop, a microcontroller triggers a servo which rings the bell with a haunting urgency.

It’s a simple build, but appropriately installed with its LED lighting, it really does pop. It would be a wonderful way to add atmosphere and mood to a Hallowe’en party or haunted house. We’ve seen some great Hallowe’en hacks over the years, and some of the best are pumpkins. Video after the break.

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Join Us For The “Holiday With Hackaday And Tindie” Meet-Up

It’s a ritual in workplaces around the world this time of any other year but 2020: the office holiday party. Too much food, perhaps too much alcohol, and garish sweaters that you wouldn’t be caught dead in on any other occasion. Things are, of course, a tad different this year, which is why we’re putting our community’s party online with the Holiday with Hackaday and Tindie meet-up on Tuesday, December 15 at noon Pacific time!

Why should you come to this hangout? Because why not! This is going to be a loose, informal meet-up that will give us all a chance to get to know one another. We’ve got an amazing community here, and just putting faces to names can be really valuable. You’ll be able to connect with old friends and perhaps make new ones. It’s your chance to reach out and find someone to collaborate with, or perhaps just find an answer to a thorny problem you’ve been stuck on. Be sure to bring your latest projects to show off, and maybe even consider giving everyone a virtual tour of your shop. Ugly sweaters are optional, of course, and we don’t judge.

The Holiday with Hackaday and Tindie meet-up is being held on Remo. Those of you who joined the Friday night Bring-a-Hack session at Remoticon this year will no doubt remember the platform, which we got a lot of good feedback on. You’ll want to check browser compatibility ahead of time and reserve your spot, so head over to Remo and make it so. If you need help with timezone conversions, we’ve got you covered on that too.

We’re looking forward to seeing everyone at the Holiday with Hackaday and Tindie meet-up!

Love Songs To The Microphone

A biographer of Frank Sinatra once commented that for singers like Sinatra, their instrument is the microphone. We tend to think of microphones as ideal transducers, picking up sound faithfully. But like most electronic components, microphones are imperfect. They have a varying frequency response. They pick up popping noises when we say words like “popcorn” that are normally lost to someone listening live.

[Cheddar] has an interesting video (see below) that covers how performers like Sinatra, Bing Crosby, and Billie Holiday learned to use the microphone to their advantage. They suggest that the microphone changed the way humans sing, and they are right.

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Christmas POV Display Makes Viewer Do The Work

Hackaday readers have certainly seen more than a few persistence of vision (POV) displays at this point, which usually take the form of a spinning LED array which needs to run up to a certain speed before the message becomes visible. The idea is that the LEDs rapidly blink out a part of the overall image, and when they get spinning fast enough your brain stitches the image together into something legible. It’s a fairly simple effect to pull off, but can look pretty neat if well executed.