Building The Stranger Things Lights For Halloween

November 1, 2026 by Zoe Skyforest 1 Comment

When Stranger Things came out all those years ago, one image left an indelible mark on pop culture. A set of Christmas lights, lined up with letters of the alphabet, such that the kid who was barely in the show could blink out messages at Winona Rider from Topsy Turvy Town. [MyEmbeddedStuff] has recreated this cross-dimensional communication system for a fun Halloween project.

The build is basically a Xiao ESP32-S3 microcontroller board and a string of WS2812B addressable RGB LEDs. To keep the Christmas-lights aesthetic, they were actually assembled in place of non-addressable LEDs in a set of existing string lights, with two LEDs per letter of the alphabet for greater brightness adding up to 52 LEDs in total. Because the letters are only lit up one at a time, total current stays low, and power is easily drawn from the power input pin of the ESP32-S3. To control the display, there’s a web server running on the ESP32 which serves up a user interface for typing in messages and having them flash out in sequence, as they did in the show.

Most of the work was in cutting the letters out of EVA foam, but there’s nothing wrong with a quick Halloween arts and crafts project with the kids. It’s a fun decoration that can add a little vibe and curiosity to a Halloween party, so you might consider building something similar yourself next year.

An Electronic Candle You Can Set On Fire

November 1, 2026 by Zoe Skyforest 7 Comments

Candles are pretty to look at, but they tend to be rather a fire risk and a negative influence on air quality, too. If you want the vibe without the hassle, you might enjoy this skeuomorphic electronic candle from [Marek.]

The build is deceptively simple for what it achieves. There is just one transistor, one thermistor, an LED, and a couple of resistors. You can “light” the candle just like a real one by heating the NTC thermistor. That’s because it makes the thermistor’s resistance drop such that the gate voltage on the MOSFET goes high enough to turn on the LED. There’s a resistor in series with the LED, which gets warm enough to keep the thermistor conductive enough to keep the MOSFET conducting in turn. However, if you blow on the assembly, you’ll cool the thermistor enough that the MOSFET stops conducting and the LED turns off.

[Marek] notes that the design is finnicky and quite subject to the vagaries of heat transfer between components; it took some fine tuning to get it working as well as it does. There’s an advanced version with a voltage regulator that helps the circuit run more reliably across a range of battery voltages if you so desire. Funnily enough, it’s also available in an SAO version as well, if you fancy an ersatz candle on your Hackaday conference badge. Neat, huh?

The only thing about [Marek’s] candle is that it doesn’t flicker like a real candle. One wonders if one of those integrated flickering LEDs could add that functionality without drastically changing the circuit, though. We’ve featured such flickery circuits before, too. Video after the break.

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Snake On A Seven-Segment Display Is Gloriously Bad

October 30, 2026 by Tom Nardi 5 Comments

You’ve no doubt heard the saying, “If something is worth doing, it’s worth doing well.” But there’s actually a counter-perspective to this particular philosophy that says it’s also worth doing things badly, with the general idea being that even a semi-successful attempt at something is better than no attempt at all.

We’re not sure if that’s the principle [José Luis Monteiro] and his father had in mind while working on a way to play the classic Snake on a seven-segment LED display salvaged from an old DVD player, but surely the end result is the same. It’s not so much that the display isn’t a good fit for the eponymous snake, in fact, it actually makes a strange amount of sense. Each of the segments can stand in for a piece of the ever-growing serpent, and they’re already arranged in a roughly rectangular grid that makes moving around straightforward enough.

The issue is that the resolution — such as it is — of the display it pretty unforgiving for anything else. Namely, the “food” that your sake is after is naturally identical to one of its own segments, so it doesn’t take long before it’s all rather confusing visually. But in those brief opening moments, it actually works pretty well.

Even if you’re not interested in Snake, between the documentation, source code, and the video below, this project is a great primer on reverse engineering these types of displays. With a microcontroller, a datasheet, and a bit of patience, you could put together an unattractive and frustrating gameplay experience of your very own! If that’s not the dream, what is?

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The Fascinating World Of IrDA And Other Infrared Protocols

October 26, 2026 by Maya Posch 32 Comments

Infrared (IR) communication technologies are probably one of the most influential, yet also one of the least flashiest. The fact that IR communication tends to be highly directional and often limited to low data rate leads many people to scoff at it, deeming it barely worthy of more than making TV remotes work, perhaps along with some unloved industrial gear like the IR interface of electrical meters.

This is a shame, because TV remotes are a good example of why sometimes you want something that is directional, and anyone who has battled with Bluetooth pairing can attest to the value of things simply working by pointing it at the device. IR protocols also have the advantage of inherent privacy protection as walls and other obstacles will block the signal, unlike that of an exploitable Bluetooth device which happily advertises to your neighbors and passersby.

For reasons like the above – as well as their simplicity and hackability – IR protocols are worthy of a detailed look.

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Another IKEA Product Yields An LED Matrix

October 10, 2026 by Jenny List 26 Comments

The IKEA Kortlinje is a digital clock that costs around 20 dollars, featuring a hygrometer and thermometer. It’s another cheap appliance, you might think, were it not that the display is a white LED matrix. Best of all, with three VK1640 LED controllers, it has hacking potential. You’re in at the ground floor if you hack one of these, but so far we’ve seen a post from the RevSpace hackerspace in the Netherlands, and the first glimmerings of a firmware on GitHub from [VIPnytt].

We have one on the bench here, and cracking it open we find the three LED drivers, an unidentified microcontroller with a 32.768 kHz watch crystal, and a mystery chip nobody’s yet identified that may either be some kind of I2C multiplexer or have something to do with those sensors. Neither has any markings, so no help there. The hackability comes in the relative ease of desoldering the microcontroller and substituting your own. In which case with access to I2C and the LED drivers, you can make it do your bidding.

This thing is part of a rich tradition of hacking IKEA products. Perhaps one of our favorites is the use of bowls from the Swedish furniture giant to make a telescope mount.

Two Microcontrollers Talking, All It Needs Is An LED

October 5, 2026 by Jenny List 10 Comments

There are some projects that seem at first sight to be easy, but anyone who tries them finds a whole heap of unexpected problems and turns to the off-the-shelf device. PCB antennas for example, or data links using LEDs, whether IR or visible. The latter doesn’t faze [Luca Soltoggio] though, because he has two ESP32s talking to each other using visible light. Best of all, both use a single LED as both transmitter and receiver.

The software is called SecurePair, and is an Arduino library for exchanging keys and communicating with encryption. The LEDs are the cool hardware hack but it’s designed to work with ESPNow or LoRa too, indeed a typical use case would see light for pairing and wireless for the exchange of encrypted data.. In case you were wondering, it relies on the property of an LED that it’s also a photodiode of sorts. Best of all, while the examples have two ESP32s, it’s not limited to that number and many more can join the conversation if needed.

Check out the video below to see it in action — if you’re curious about LEDs as sensors, we’ve been there too.

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ESP32 Replacement For Lighting Display Controller

September 22, 2026 by Bryan Cockfield 1 Comment

As a company, NanoLeaf has been producing modular lights that can be easily snapped together into various geometric shapes for around a decade. Similar to the addressable LED light strips many of us are familiar with that also became popular around a decade ago, these modular lights are supposed to be easy to configure, customize, and program. But their controllers are notoriously finicky according to [Myrik] who found that a simple ESP32 could be used to replace them when they eventually fail.

Part of the reason [Myrik] found this to be straightforward is that the company publishes their firmware and makes it essentially available to anyone. Whether or not this was purposeful is not clear; but in either case it only requires slight modification to run on the ESP32. When plugged into an existing string of panels, the panels themselves report their positions and orientations over a single data bus which the ESP32 has no problem interpreting. The ESP32 can also communicate its status over the network, meaning that it can in turn be controlled by any other lighting software a user might have.

There’s a separate Reddit post about this build as, with other users offering other potential solutions to the controller issue. But we are always happy to see more open solutions to hardware failures which keep interesting things like these out of the e-waste pile, or simply building NanoLeaf-inspired replicas from the ground up in the first place.