A small PCB with a microcontroller, two 7-segment LED displays, a speaker and some buttons

Hunt The Lunpus Is An ATtiny-Based Minimalist Game Console

July 22, 2022 by Robin Kearey 9 Comments

In a world where game consoles come with ever-higher resolutions and ever-faster frame rates, it’s refreshing to see someone going in the opposite direction: [Doug McInnes]’s latest project is a tiny handheld game console with probably the lowest-resolution graphics possible. Hardware-wise, it’s a small PCB containing an ATtiny84, two seven-segment LED displays, a speaker and a handful of buttons. It’s the software that gives this project its magic, and all of it is available on GitHub, along with schematics and a PCB layout.

The game is called Hunt the Lunpus, and as the name suggests it’s inspired by the 1970s classic Hunt the Wumpus. The player moves through a maze of interconnected rooms, trying to avoid slime pits and marauding bats while searching for the Lunpus, a sleeping monster that will eat the player unless they defeat it first by shooting it with arrows. Four pushbuttons provide directional control, with a fifth serving as an “action” button to start the game and fire those arrows.

Whereas Wumpus was originally a text-based adventure game, Lunpus is fully graphical: the seven-segment displays indicate the cave’s walls, and flash in different ways to alert the player to the various hazards. [Doug] explains the events as they happen in the video embedded below; while it might take a bit of practice to find your way at first, we can already picture ourselves wandering through the caves with our quiver full of arrows, ready to hunt some Lunpus. Who needs 4K graphics, anyway?

If you’re into minimalist game consoles, there’s plenty to choose from: the LEDBOY renders Space Invaders on just a few LEDs, while TWANG needs nothing more than a single LED strip. You can also explore more mazes on this 8×8 LED matrix, or even hunt Wumpuses in a slightly-higher resolution.

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A clock made with LED filaments inside clear plastic tubes

LED Filaments Make A Retro Clock Without Any Retro Parts

April 5, 2022 by Robin Kearey 9 Comments

We love clock projects here at Hackaday, and we’ve seen many beautiful designs based on a wide variety of display technologies. There are various types of glass tubes like Nixies, Numitrons and classic VFD displays, all of which have that warm “retro” glow to them. Then there’s LEDs, which are useful for making cool pixel-based timepieces and easy to drive with low-voltage electronics. So how about combining the best of both worlds, by using LEDs to make a Numitron-like display? That’s exactly what [Jay Hamlin] did when he built a digital clock based on LED filaments.

The heart of the project consists of orange LED filaments similar to the ones used in vintage-style LED light bulbs. [Jay] bought a bunch of them online and tried various ways of combining them into seven-segment displays, eventually settling on a small PCB with a black finish to give good contrast between the LEDs and the background. To make the displays look like they’re encased in glass, [Jay] bought a set of plastic test tubes and cut them to size.

The base of the clock is formed by a slick black PCB that holds an ESP32. The segments are driven through a set of 74LV595 shift registers to keep the required number of GPIOs to a minimum. There are no buttons: thanks to a WiFi connection and the Network Time Protocol the ESP32 automatically keeps the correct time.

The end result looks remarkably like a Numitron display at first glance, and remains a beautifully-made clock even if you notice that there’s no glass to be found. If you’re into LED filament clocks (and who isn’t?), check out this analog wall clock, or this spiderweb-like digital clock.

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Simple Arduino Build Lets You Keep An Eye On Pi

March 15, 2022 by Tom Nardi 10 Comments

Are you a math aficionado in need of a new desk toy? Then do we have the project for you. With nothing more than an Arduino and a seven-segment LED module, [Cristiano Monteiro] has put together a little gadget that will slowly work its way through the digits of Pi forever…or until you get bored of looking at it and decide to use the parts for something else.

On the hardware side, we really can’t overstate how simple this project is. A common four-digit LED display is connected up to an Arduino Nano, which is then plugged into the computer for power. [Cristiano] is using a breadboard here, but you could just as easily use four female-to-female jumpers to connect the two devices together. We suppose this would be a pretty good project for anyone who’s looking to get some practical experience with PCB design as well.

The real magic is in the software, which [Cristiano] has been kind enough to release under the MIT license. Calculating Pi on such a resource-constrained chip as the ATmega328P is far from ideal, but by porting over a C++ algorithm developed by [Xavier Gourdon] and [Pascal Sebah] for their paper Computation of the n-th Decimal Digit of π with Low Memory he was able to pull it off, albeit slowly.

Now if you’ve got slightly better hardware, say a pair of Xeon processors and 96 GB of RAM, you could calculate Pi out to a few trillion digits for fun, but it wouldn’t look as cool as this little guy blinking away.

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Watch Life Tick Away, One LED Segment At A Time

December 21, 2020 by Tom Nardi 15 Comments

In the grand scheme of things, a single human lifetime is a drop in the bucket. Even if we don’t like to acknowledge it, we all know the meter is running so to speak. Yet you’re still squandering your precious time on this Earth by reading Hackaday instead of doing something constructive. Of course nobody is burning up more time on this site than those of us who are writing it all, so don’t feel too bad.

To remind us that life is fleeting, [Dries Depoorter] has designed the Shortlife: a device that counts down until your expected departure date. Before you get too excited, it can’t predict the future. The gadget is programmed with the vital statistics for the individual user, and data provided by the World Health Organization is used to calculate how much of your estimated life expectancy has already elapsed. Some would find this information depressing, while others will no doubt look at it as a source of inspiration. Us? We just think its a slick piece of gear.

The Shortlife is made up of a custom PCB mounted to a marbled block of recycled plastic. On the board there’s an ATmega328 microcontroller, a MAX7219 LED driver, and of course the red LED segment displays. Three of them are the classic seven count, while the rightmost display sports fourteen segments for a bit of added accuracy. All the user has to do if they want to watch their remaining time slip away is plug the device into a USB power source and set the current time.

We’ve seen similar mortal countdown clocks in the past, but the Shortlife certainly brings a certain level of elegance to the idea. Plus we also like the fact that you’re just a line of code or two away from having the display tick down to some other date in the future when that whole existential crisis kicks in

UV Phone Sanitizer Shows The Power Of Modern DIY

June 8, 2020 by Tom Nardi 94 Comments

Editor’s Update: According to the schematic for this project, SST-10-UV-A130-F405-00 (PDF) LEDs are used which produce 405nm UV-A light. The manufacturer, Luminus, does not recommend that part for disinfection or sterilization. Luminus sells UV-C LEDs for that purpose, generating 275-285nm. After publication the part number used was changed to and American Opto L933-UV265-2-20 which is a UV-C LED producing 265-278nm.

The global COVID-19 pandemic has had a serious impact on the hacking and making scene, though it hasn’t been all bad. Sure, shipping on average is taking a lot longer than we’d like when ordering parts, but otherwise being stuck at home has given many people far more time to work on their projects than they would have had otherwise. In some cases, it’s also been a reminder of just how far we’ve come in terms of what the dedicated individual is capable of producing within the confines of their own home.

As a perfect example, take a look at this UV sanitizer box built by [Md Raz]. Looking for a way to quickly and easily kill germs on smartphones and other small devices, he used the considerable capabilities afforded to the modern hacker to produce a professional-looking device in far less time than it would have if he had to outsource things like PCB manufacturing or injection molding.

Inside the 3D printed enclosure is an array of SMD UV-C LEDs that, according to the manufacturer’s specs, will destroy viruses and bacteria in 5 minutes. To make sure the LEDs are given enough time to do their job, [Md] is using an ATtiny85 to control the countdown and a seven segment display to let the user know how much longer they have to wait. All the electronics are held on PCBs produced with a BotFactory SV2 desktop PCB printer, but for those of us with somewhat more limited budgets, a mill or even a modified laser engraver could be used to produce similar boards.

With everything going on, there’s understandably been increased demand for germicidal lights. But unfortunately, some unscrupulous manufacturers are trying to take advantage of the situation. Being able to select the LEDs for this device based on their specifications is arguably just as important as how quickly it was produced. Though we’d still advise a position of “trust, but verify” when it comes to UV-C.

Viewing Countrywide Weather At A Glance

May 3, 2020 by Tom Nardi 5 Comments

For his latest project, weather display aficionado [Richard] has put together a handsome little device that shows the temperatures recorded at nine different airports located all over the British Isles. Of course the concept could be adapted to wherever it is that you call home, assuming there are enough Internet-connected weather stations in the area to fill out the map.

The electronics are fairly minimal, consisting of a NodeMCU ESP8266 development board, a few seven segment LED display modules, and a simple power supply knocked together on a scrap of perfboard. As you might expect, the code is rather straightforward as well. It just needs to pull down the temperatures from an online API and light up the displays. What makes this project special is the presentation.

As [Richard] shows in the video after the break, the key is a sheet of acrylic that’s been sanded so it diffuses the light of 42 LEDs that have been painstakingly installed in holes drilled around the edge of the sheet. Combined with a printed overlay sheet, this illuminates the map and its legend in low-light conditions. It’s a simple technique that not only looks fantastic, but makes the display easy to read day or night. Definitely a tip worth mentally filing away, as it has plenty of possible applications outside of this particular build.

With his projects, [Richard] has shown himself to be a master of unique and data-rich weather displays, and a great lover of the iconic seven segment LED display. While his particular brand of climate data overload might not be for everyone, you’ve got to admire his knack for visualizing data.

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Bask In The Glory Of This 336 LED Digit Display

January 18, 2020 by Tom Nardi 12 Comments

[Chris Combs] recently took the wraps off of an incredible art piece that he calls Road Ahead which uses 336 seven segment LED digits to create an absolutely gorgeous display. With a piece of smoked acrylic to slightly diffuse the orange glow of the LEDs, the end result has a distinctively retro look that we’d gladly spend all day staring at.

For those looking to dig a bit deeper, [Chris] has put together some very impressive documentation over on Hackaday.io that goes into plenty of detail on how he designed and built this beauty. From the design of the PCBs that carry all of the 0.3″ SMD displays to the custom software running on the Raspberry Pi 3 that powers it, there’s no technical stone left unturned.

According to the build log, this is the second version of the display. The first one was housed in a rather attractive wooden enclosure, but as [Chris] explains, that was precisely the problem. He wanted something that looked cold and unfeeling as the nearly 340 digits flashed away with potentially ominous intent. So he ditched the wooden case for a powder coated steel one that looks more like the front panel of a mainframe than something you’d pick up at the craft store.

Another interesting point explained in the write-up is how the Python software is designed to treat the hardware as a contiguous graphical display rather than just an array of independent digits. Grayscale images can be reproduced on the by using PWM to adjust the brightness of each segment’s corresponding “pixel”; though admittedly it takes a bit of imagination to see the intended image with a resolution this low.

This project reminds us of the incredible LED hexdump display we saw not that long ago, down to the PWM trickery for squeezing “graphics” out of these exceptionally non-graphical elements. With any luck, perhaps these are the opening shots in an arms race to see who can build the largest array of multi-segment LED displays.