Hackaday Podcast 189 is one of those episodes that feels like opening a junk drawer in the best possible way. You reach in expecting maybe a resistor, a half-charged LiPo, and three mystery screws. Instead, you pull out mechanical seven-segment displays, an e-reader with hot-swappable keyboard switches, a tiny LED candle that does more with code than some office printers do with firmware, and a Supercon badge that politely asks modern developers to remember what bits are.
Originally published in October 2022, this episode brought together Hackaday’s maker-minded style: practical builds, oddball engineering, retrocomputing nostalgia, and just enough “why would anyone do this?” energy to make the answer obvious: because it is fun, educational, and occasionally glows.
This article explores the major themes behind the episode, including seven-segment display reinvention, candle simulation code, DIY e-reader design, the 2022 Supercon badge reveal, and the broader lessons these projects offer to hardware hackers, embedded developers, and anyone who has ever said, “I can build that,” immediately before ordering parts at midnight.
Why Hackaday Podcast 189 Still Feels Fresh
The strength of Hackaday Podcast 189 is not only the number of projects discussed. It is the range. One minute, the conversation is about the strange elegance of a seven-segment display. The next, it is about turning a Raspberry Pi into a phone, building a homebrew e-reader, simulating flame behavior with addressable LEDs, or programming a conference badge like a miniature retrocomputer.
That variety is exactly what makes the maker community interesting. Hardware hacking is rarely a straight line from problem to solution. It is more like a pinball machine where the ball bounces between electronics, code, industrial design, nostalgia, cost limits, and one unavoidable truth: the enclosure always takes longer than expected.
The episode’s headline topics share a common thread. Each project takes a familiar object and asks what happens when the builder refuses to accept the default version. A display does not have to be a normal display. A candle does not need actual fire. An e-reader does not need to copy a Kindle. A badge does not have to be a passive name tag. That is the Hackaday spirit in a nutshell: take the ordinary, add curiosity, and see what breaks in an educational way.
Seven-Segment Displays: Old Idea, New Mischief
Seven-segment displays are among the most recognizable parts in electronics. They appear in calculators, clocks, meters, appliances, fuel pumps, lab equipment, and any device that wants to say “42” with confidence. Their basic job is simple: use seven individually controlled segments to represent digits. Their cultural job is bigger: they look like electronics. Show someone red seven-segment numerals in a dark room and they will instantly assume something is counting down, measuring voltage, or threatening the moon.
In the episode, the “seven segments three ways” idea points to a wider theme: even a display format that has been around for decades can still be redesigned. Hackaday highlighted unusual takes on the format, including mechanical and printable approaches that treat digits not as pixels but as physical geometry. That shift matters. When numbers are built from sliders, cams, flaps, or printed pieces, the display becomes a mechanism rather than just an output device.
Why Reinvent a Display That Already Works?
Because constraints are creative fuel. A normal LED seven-segment module is cheap, bright, compact, and easy to drive. That makes it excellent for practical work but less interesting as an experiment. A mechanical seven-segment display, on the other hand, makes every digit feel intentional. It turns information into movement.
This is especially valuable for learning. A beginner can wire a basic seven-segment LED display and understand multiplexing, current limiting, GPIO control, and binary-to-decimal display logic. A more advanced builder can explore stepper motors, servos, magnets, linkages, 3D printing tolerances, and mechanical wear. Suddenly, “display the number 8” becomes a full engineering conversation, which is a very maker-ish way to make a simple task delightfully complicated.
The best seven-segment experiments also remind us that design is not only about efficiency. Sometimes the point is personality. A mechanical digit that clacks into position has charm. A slider-based digit that requires manual adjustment has puzzle-box energy. A display with unusual segment shapes may be less practical than a commodity module, but it can be more memorable. In a world full of black rectangles, weird hardware earns applause.
Candle Code: Making LEDs Behave Like Fire
One of the episode’s most charming topics is the LED candle project. At first glance, simulating a flame sounds simple. Turn an LED orange, wiggle the brightness, and call it a day, right? Congratulations, you have invented a nervous traffic cone.
A convincing candle is harder. Real flame has rhythm, randomness, color variation, and subtle motion. It flickers, but not like a bad connection. It shifts intensity, but not like a metronome. It has a living quality that comes from messy physics: air currents, fuel behavior, heat, turbulence, and combustion. Recreating that with code requires a careful balance between randomness and pattern.
The NeoCandle-style project discussed around this episode used a small ATtiny85 microcontroller, WS2812-style addressable LEDs, infrared control, and compact code techniques. That combination is a tiny embedded-systems playground. The ATtiny85 offers very limited memory compared with modern boards, which means every byte matters. The result is a project where clever code is not optional decoration; it is the whole magic trick.
The Beauty of Small Microcontroller Projects
Small chips force better thinking. When memory is limited, developers stop casually importing libraries as if flash storage grows on trees. Timing matters. Data structures matter. Randomness matters. Even the decision to use a linear feedback shift register for pseudo-random behavior becomes meaningful because it can generate pleasing variation without wasting precious resources.
Addressable LEDs such as NeoPixels are also a great teaching tool because they combine electronics and software timing. They do not simply turn on when connected to power. They need data. That data must be sent in the correct order, with the correct timing, from a microcontroller that may also be reading sensors, decoding remote-control signals, and trying not to run out of memory. It is a tiny circus, and the ringmaster has 8 KB of flash.
The result is more than a seasonal decoration. It is a lesson in embedded design: know your hardware, respect timing, write lean code, and never underestimate how much engineering can hide inside something shaped like a cute ghost.
DIY E-Readers: When Page-Turn Buttons Make a Comeback
The DIY e-reader highlighted in Hackaday Podcast 189 taps into a feeling many early e-reader fans understand: physical buttons were good. Touchscreens are flexible, yes, but there is something wonderfully direct about pressing a real switch to turn a page. It feels like using a tool, not negotiating with a pane of glass.
The project used an e-paper display, a compact Raspberry Pi-style computing setup, and an Adafruit NeoKey board with hot-swappable mechanical key sockets. That last detail gives the build its personality. Mechanical keyboard switches on an e-reader sound absurd until you imagine clicking to the next page with a satisfying tactile bump. Then it sounds obvious. Dangerous, but obvious.
E-paper itself is perfect for this kind of project because it behaves differently from LCD or OLED screens. Instead of constantly emitting light, many e-paper displays rely on electrophoretic technology, where charged particles move under an electric field to create visible black and white areas. The display can hold an image with very low power, making it excellent for reading, labels, dashboards, calendars, and slow-refresh information panels.
The DIY E-Reader Challenge
Building a homemade e-reader is not just a matter of attaching a screen. The hardware needs power management, input controls, a case, and a display driver. The software needs to parse text formats, render pages, manage fonts, handle page turns, and avoid making readers wait so long that they forget the plot.
The Hackaday-covered project used EPUB processing tools and display drivers to convert book content into something the e-paper screen could show. That is where the real work lives. Commercial e-readers hide a mountain of complexity: typography, margins, battery life, refresh modes, storage, sleep behavior, and user interface polish. A DIY version makes those hidden systems visible.
That visibility is valuable. A homebrew e-reader teaches more than a store-bought device ever will. It shows how digital books become rendered pages, how slow-refresh displays affect interface design, and how input hardware changes the reading experience. It also proves that “obsolete” ideas like page-turn buttons may not be obsolete at all. Sometimes they were just waiting for someone with a 3D printer and strong opinions.
The 2022 Supercon Badge Reveal: Retrocomputing You Can Wear
The 2022 Hackaday Supercon badge was not merely a shiny conference accessory. It was a handheld lesson in computing history. Instead of chasing the most powerful badge possible, the design leaned into retrocomputing concepts: front-panel interaction, binary entry, LEDs, buttons, and a virtual 4-bit processor.
This choice is important because modern computing often hides the machine from the user. We tap icons, drag windows, and call APIs, but the bits are buried under layers of abstraction. The Supercon badge did the opposite. It brought the bits back to the surface and made users interact with them directly.
That can be humbling. Entering instructions bit by bit is slower than writing code in a modern editor. It is also unforgettable. When a person manually deposits opcodes, steps through memory, and watches LEDs represent state, computing stops being magic. It becomes a physical process. That is exactly the kind of educational friction good hardware can provide.
Why Badges Matter in Hacker Culture
Electronic conference badges have become a subculture of their own. Some include radios, sensors, displays, games, expansion headers, and hidden modes. The best ones become social objects. People trade hacks, compare firmware, write demos, and discover features together in hallways, workshops, and late-night hotel-room debugging sessions.
The 2022 Supercon badge stood out because it emphasized understanding over raw specifications. That is a refreshing message. Bigger chips and brighter screens are fun, but they are not the only path to a great badge. A limited system can be more educational because it invites users to understand every part. In other words, the badge was not saying, “Look how powerful I am.” It was saying, “Look closer.”
Side Quests: Raspberry Pi Phones, Crash Detection, and Artificial Suns
Like many Hackaday Podcast episodes, number 189 did not stay in one lane. It also touched on a Raspberry Pi phone build, iPhone crash detection being triggered by roller coasters, and a futuristic artificial-sun headboard. These side quests broaden the episode from “cool projects” into a snapshot of the maker world’s bigger questions.
The Raspberry Pi phone project asks what a smartphone really is. Strip away branding and polish, and a phone is a small computer with radios, audio hardware, a battery, a display, and software that coordinates the whole circus. Building one from maker parts does not necessarily produce a better daily driver, but it teaches how much integration commercial phones hide.
The iPhone crash-detection discussion raises another issue: sensors are powerful, but context is hard. Accelerometers, gyroscopes, microphones, GPS, and barometers can help detect severe car crashes, but unusual environments such as amusement rides can resemble emergency conditions to an algorithm. The technology can be genuinely useful, yet false positives show why real-world sensor interpretation is complicated.
The artificial-sun headboard adds a more domestic flavor. It combines lighting, furniture, voice control, 3D printing, Arduino boards, and wake-up automation. It is a reminder that hardware hacking is not limited to benches and labs. Sometimes it lives in bedrooms, kitchens, garages, and anywhere else a person looks at a normal object and thinks, “This could use a microcontroller.”
What These Projects Teach About Modern Making
The projects in Hackaday Podcast 189 are different on the surface, but they share several lessons that apply to almost any hardware project.
1. Constraints Make Projects Better
A tiny microcontroller, a slow e-paper display, a 4-bit virtual CPU, or a mechanical digit system may sound limiting. In practice, those limits give the project shape. They force the builder to make decisions instead of hiding behind excess resources.
2. Interfaces Matter
Buttons, LEDs, sliders, displays, and tactile switches are not afterthoughts. They define how people experience hardware. The DIY e-reader would feel different without mechanical page keys. The Supercon badge would lose its soul without front-panel buttons. The seven-segment display experiments would be far less charming if they were just pixels on a screen.
3. Old Technology Is Not Dead
Seven-segment displays, front panels, binary entry, and physical switches may feel old-fashioned, but they remain useful teaching tools. Retro hardware ideas survive because they make invisible concepts visible.
4. Small Projects Can Contain Big Engineering
A fake candle can teach timing, randomness, memory limits, and LED control. A simple e-reader can teach file parsing, typography, power management, and user interface design. A badge can teach processor architecture. Never judge a project by its enclosure size.
Hands-On Experiences Inspired by Hackaday Podcast 189
For anyone building projects like the ones discussed in Hackaday Podcast 189, the first experience is usually excitement. The second experience is discovering that one missing connector has stopped the entire weekend. This is normal. In maker culture, progress often arrives in waves: research, ordering parts, waiting, soldering, debugging, questioning reality, and finally celebrating when one LED blinks exactly as intended.
A seven-segment display project is a great starting point because it gives fast visual feedback. Wiring a basic module teaches current limiting and pin control. Driving multiple digits teaches multiplexing. Building a mechanical version teaches patience, tolerances, friction, and the humbling truth that plastic parts do not care about your CAD confidence. If a slider sticks, the number looks wrong. If a linkage is sloppy, the digit becomes abstract art. That feedback is immediate and useful.
An LED candle project feels simple until the animation begins. A regular blink looks fake. A sine wave looks too smooth. Pure randomness looks chaotic. The best flame effect usually comes from layered behavior: slow brightness drift, small rapid flickers, slight color shifts, and occasional dimming. Testing it in a dark room helps. So does asking someone else if it looks like fire, because after staring at LEDs for two hours, your brain may approve anything that is not a compiler error.
A DIY e-reader is more ambitious. The display refresh rate changes how the whole interface must work. Menus need to be simple. Page turns need to be predictable. Fonts matter more than expected. Mechanical keys can make the device feel delightful, but they also affect layout, enclosure design, and power use if LEDs are involved. The biggest lesson is that reading devices are not only screens; they are comfort machines. Weight, grip, button position, contrast, and battery behavior all matter.
The Supercon badge style of project offers a different experience: mental rewiring. When users enter binary instructions manually, they slow down enough to understand the machine. That is uncomfortable at first, especially for people used to high-level programming. But it creates a lasting connection between code and hardware. A single LED changing state can feel more satisfying than a polished app animation because the user knows exactly why it happened.
The best practical advice from these experiences is to document everything. Take photos before closing the case. Label wires. Save code versions. Write down what failed. Future-you will not remember which pin was changed at 1:17 a.m., no matter how confident present-you feels. Future-you is tired and deserves comments.
Most importantly, these projects show that making is not about producing perfect products. It is about learning through friction. A homemade e-reader may never replace a commercial Kindle. A microcontroller candle may not fool a fireplace enthusiast. A retro badge may not outperform a modern development board. That is fine. Their value is in the process: touching the layers of technology that finished products politely hide from view.
Conclusion: A Podcast Episode Built for Curious Hands
Hackaday Podcast 189: Seven Segments Three Ways, Candle Code, DIY E-Readers, And The Badge Reveal works because it celebrates the messy, clever, deeply human side of engineering. It is not just about finished gadgets. It is about the decisions inside them: why use physical keys, why simulate fire on a tiny chip, why program a badge bit by bit, and why reinvent a seven-segment display when perfectly good ones already exist?
The answer is simple: because building is how makers think. These projects turn familiar objects into lessons. They make technology visible, tactile, and hackable. They remind us that hardware does not need to be new to be interesting, and software does not need to be huge to be clever.
Whether you are into embedded systems, retrocomputing, e-paper displays, LED art, or conference badge hacking, this episode is a compact tour through the joy of making things the wonderfully difficult way. And honestly, that is usually the best way.
