A Musically-Reactive LED Christmas Tree

December 10, 2025 by Lewin Day 6 Comments

Regular Christmas trees don’t emit light, nor do they react to music. If you want both things in a holiday decoration, consider this build from [dbmaking].

An ESP32-D1 mini runs the show here. It’s hooked up to a strip of WS2812B addressable LEDs. The LED strip is placed on a wooden frame resembling the shape of a traditional Christmas tree. Ping-pong balls are then stacked inside the wooden frame such that they act as a light diffuser for the LEDs behind. The microcontroller is also hooked up to an INMP441 omnidirectional MEMS microphone module. This allows the ESP32 to detect sound and flash the LEDs in time, creating a colorful display that reacts to music. This is achieved by using the WLED web installer to set the display up in a sound reactive mode.

It’s a fun build, and we’d love to tinker around with coding more advanced visualizer effects for a build like this. We’ve seen builds that go the other way, too, by toning down excessive blinkiness in Christmas decorations.

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Dark lab setup with scientific looking drink dispenser

Scared For A Drink?

October 31, 2025 by Heidi Ulrich 1 Comment

Halloween is about tricks and treats, but who wouldn’t fancy a bit to drink with that? [John Sutley] decided to complete his Halloween party with a drink dispenser looking as though it was dumped by a backstreet laboratory. It’s not only an impressive looking separating funnel, it even runs on an Arduino. The setup combines lab glassware, servo motors, and an industrial control panel straight from a process plant.

The power management appeared the most challenging part. The three servos drew more current than one Arduino could handle. [John] overcame voltage sag, brownouts, and ghostly resets. A healthy 1000 µF capacitor across the 5-volt rail fixed it. With a bit of PWM control and some C++, [John] managed to finish up his interactive bar system where guests could seal their own doom by pressing simple buttons.

This combines the thrill of Halloween with ‘the ghost in the machine’. Going past the question whether you should ever drink from a test tube – what color would you pick? Lingonberry juice or aqua regia, who could tell? From this video, we wouldn’t trust the bartender on it – but build it yourself and see what it brings you!

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Building A Minecraft Lantern For Halloween

October 21, 2025 by Lewin Day 5 Comments

Sometimes it’s fun to bring props from video games into the real world. [Hulk] has done just that with their latest Halloween build—creating a working replica of the lantern from Minecraft.

Key to the build is the 3D printed enclosure, which faithfully mimics the look of the in-game item. By virtue of Minecraft’s simplistic visual style, it’s a relatively straightforward print, without a lot of quirky geometry or difficult overhangs that might otherwise trip up your printer. It’s printed in six parts and assembled with acrylic lenses which act to diffuse the light coming from inside.

Electronically, an Arduino Nano runs the show. It’s hooked up to a pair of NeoPixel addressable LED rings, which provide rich RGB colors on demand. Rotary pots are installed on the enclosure to enable the color to be tuned to the user’s desire. Power is courtesy of an 18650 lithium-ion cell and a TP4056 module ensures the battery is kept happy when charging.

It’s a fun prop build, and one that would be the perfect addition to any Minecraft costume. Except for maybe a chicken jockey, because they don’t use lanterns. In any case, we’ve seen similar work before, too.

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Trapped Soul In Time For Halloween

September 25, 2025 by Al Williams 7 Comments

While it is sort of disturbing, it is one of the best uses for a round LCD we’ve seen lately. What is it? Just [vishalsoniindia]’s SoulCage — a pendant that appears to have a poor soul trapped inside of it. Just in time for the upcoming spooky holiday. You can see the device in operation in the short video below.

The heart (sorry, unintentional pun) of the device is an ESP32-S3 round display. That means the rest of it is software, a battery, and a 3D printed case. There’s a switch, too, to select a male or female image as well as shut the device off when not in use.

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A photo of the vending machine sitting on an electronics workbench

Building A Halloween Vending Computer That Talks

September 1, 2025 by John Elliot V 1 Comment

Our hacker from [Appalachian Forge Works] wrote in to let us know about their vending machine build: a Halloween vending computer that talks.

He starts by demonstrating the vending process: a backlit vend button is pressed, an animation plays on the screen as a synthetic voice speaks through attached speakers, the vending mechanism rotates until a successful vend is detected with a photoelectric sensor (a photoresistor and an LED) or a timeout of 10 seconds is reached (the timeout is particularly important for cases when the stock of prizes is fully depleted).

For a successful vend the prize will roll out a vending tube and through some ramps, visible via a perspex side panel, into the receptacle, as the spooky voice announces the vend. It’s the photoelectric sensor which triggers the mask to speak.

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Water Jets Will Carve Your Pumpkin

February 20, 2025 by Lewin Day 8 Comments

Carving pumpkins by hand is hot, sweaty, messy work, and a great way to slice your way into a critical artery. Why not let a water jet do it for you? It’ll be cleaner and more precise to boot, and [Jo_Journey] is here to show us how.

Obviously, you’ll need a water jet machine, there’s no getting around that. You’ll also still have to do the basic preparation of the pumpkin yourself—cutting a porthole into the top and mucking it out is your job. With that done, you must then mount the pumpkin on two metal rods which will be used to mount it in the water jet machine’s working area.

You can then create a vector file of your design, and use your chosen software to generate the G-code to run the water jet. [Jo_Journey] uses Scribe, and recommends cutting at a speed of around 200 in/min at low pressure. Remember, it’s pumpkin you’re cutting, not high-strength steel.

There is some inaccuracy, of course—your pumpkin’s surface is not a flat plane, after all—but the results are good enough for most Halloween-related purposes. Even despite the geometrical issues, though, [Jo_Journey] shows us that you can get pleasantly sharp edges on your design. That’s very hard to achieve by hand!

We do love a good holiday hack around these parts, even if it’s out of season. If you’ve been cooking up your own pumpkinous plans, don’t hesitate to let us know! Earlier is sometimes better—after all, who has time to hack together a project if you’ve just read about it on October 29?

555 Timers Bring Christmas Charm To Miniature Village

January 2, 2025 by Tom Nardi 10 Comments

The miniature Christmas village is a tradition in many families — a tiny idyllic world filled happy people, shops, and of course, snow. It’s common to see various miniature buildings for sale around the holidays just for this purpose, and since LEDs are small and cheap, they’ll almost always have some switch on the bottom to light up the windows.

This year, [Braden Sunwold] and his wife started their own village with an eye towards making it a family tradition. But to his surprise, the scale lamp posts they bought to dot along their snowy main street were hollow and didn’t actually light up. Seeing it was up to him to save Christmas, [Braden] got to work adding LEDs to the otherwise inert lamps.

Now in a pinch, this project could have been done with nothing more than some coin cells and a suitably sized LED. But seeing as the lamp posts were clearly designed in the Victorian style, [Braden] felt they should softly flicker to mimic a burning gas flame. Blinking would be way too harsh, and in his own words, look more like a Halloween decoration.

This could have been an excuse to drag out a microcontroller. But instead, [Braden] did as any good little Hackaday reader should do, and called on Old Saint 555 to save Christmas. After doing some research, he determined that a trio of 555s rigged as relaxation oscillators could be used to produce quasi-random triangle waves. When fed into a transistor controlling the LED, the result would be a random flickering instead of a more aggressive strobe effect. It took a little tweaking of values, but eventually he got it locked down and sent away to have custom PCBs made of the circuit.

With the flicker driver done, the rest of the project was pretty simple. Since the lamp posts were already hollow, feeding the LEDs up into them was easy enough. The electronics went into a 3D printed base, and we particularly liked the magnetic connectors [Braden] used so that the lamps could easily be taken off the base when it was time to pack the village away.

We can’t wait to see what new tricks [Braden] uses to bring the village alive for Christmas 2025. Perhaps the building lighting could do with a bit of automation?

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