A Guide For Driving LED Matrices

November 27, 2018 by 8 Comments

Building an LED matrix is a fun project, but it can be a bit of a pain. Usually it starts with hand-soldering individual LEDs and resistors together, then hooking them up to rows and columns so they can be driven by a microcontroller of some sort. That’s a lot of tedious work, but you can order an LED matrix pre-built to save some time and headache. You’ll still need a driver though, and while building one yourself can be rewarding there are many pitfalls and trade-offs to consider when undertaking that project as well. Or, you can consider one of a number of drivers that [deshipu] has outlined in detail.

The hangups surrounding the driver board generally revolve around the issue of getting constant brightness from LEDs regardless of how many in the row or column are illuminated at one time. Since they are typically driven one row or column at a time, the more that are on the lower the brightness each LED will have. Driver boards take different approaches to solving this problem, which usually involve a combination of high-speed scanning of the matrix or using a constant-current source in order to eliminate the need for resistors. [deshipu] outlines four popular chips that achieve these purposes, and he highlights their pros and cons to help anyone looking to build something like this.

Most of these boards will get you to an 8×8 LED matrix with no problem, with a few going a few pixels higher in either direction. That might be enough for most of our needs, but for something larger you’ll need other solutions like the one found in this 64×32 LED matrix clock. There are also even more complicated drivers if you go into extra dimensions.

Photo credit: Komatta [Public domain], from Wikimedia Commons

Flywire Circuits At The Next Level

November 19, 2018 by 40 Comments

The technique of assembling circuits without substrate goes by many names; you may know it as flywiring, deadbugging, point to point wiring, or freeform circuits. Sometimes this technique is used for practical purposes like fixing design errors post-production or escaping tiny BGA components (ok, that one might be more cool than practical). Perhaps our favorite use is to create art, and [Mohit Bhoite] is an absolute genius of the form. He’s so prolific that it’s difficult to point to a particular one of his projects as an exemplar, though he has a dusty blog we might recommend digging through [Mohit]’s Twitter feed and marveling at the intricate works of LEDs and precision-bent brass he produces with impressive regularity.

So where to begin? Very recently [Mohit] put together a small wheeled vehicle for persistence of vision drawing (see photo above). We’re pretty excited to see some more photos and videos he takes as this adorable little guy gets some use! Going a little farther back in time there’s this microcontroller-free LED scroller cube which does a great job showing off his usual level of fit and finish (detail here). If you prefer more LEDs there’s also this hexagonal display he whipped up. Or another little creature with seven segment displays for eyes. Got those? That covers (most) of his last month of work. You may be starting to get a sense of the quality and quantity on offer here.

We’ve covered other examples of similar flywired circuits before. Here’s one of [Mohit]’s from a few years ago. And another on an exquisite headphone amp encased in a block of resin. What about a high voltage Nixie clock that’s all exposed? And check out a video of the little persistence of vision ‘bot after the break.

Thanks [Robot] for reminding us that we hadn’t paid enough attention to [Mohit]’s wonderful work!

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Hackaday Meetup At Electronica: Thursday

November 13, 2018 by 10 Comments

Hackaday’s parent company Supplyframe is at Electronica in Munich this week — booth C5-223. On Thursday from 16:00 – 18:00, they’ll be hosting a Hackaday Happy Hour, with a beer and coffee bar, for everyone in the Hackaday community. They’d love to see you and hear what you’re working on, be it for your day job or your night job.

If you missed the #badgelife exhibit at Supercon, it’s here at Electronica. There will also be some of those mysterious cubes you may have heard about. Richard Hogben and Bogdan Rosu will be DJing fresh beats. Stop by and say hi to [Sophi Kravitz], [Majenta Strongheart], [Alek Bradic], and everyone else from the Supplyframe team.

Hackaday’s own [Elliot Williams] will also be wandering around Electronica Wednesday afternoon. He can’t promise free beer, but if you want to crawl around Electronica with [Elliot], meet up at the Supplyframe booth at 14:30 on Wednesday.

Popup Notification Dinosaur

October 18, 2018 by 1 Comment

There’s a lot going on our virtual spaces, and anyone with a smart phone can attest to this fact. There are pop-up notifications for everything you can imagine, and sometimes it’s possible for the one really important notification to get lost in a sea of minutiae. To really make sure you don’t miss that one important notification, you can offload that task to your own personal dinosaur.

The 3D-printed dinosaur has a rack-and-pinion gear set that allows it to extend upwards when commanded. It also has a set of LEDs for eyes that turn on when it pops up. The two servos and LEDs are controlled by a small Arduino in the base of the dinosaur. This Arduino can be programmed to activate the dinosaur whenver you like, for an email from a specific person, a reply to a comment on Reddit, or an incoming phone call to name a few examples. Be sure to check out the video below the break.

With this dinosaur on your desk, it’s not likely you’ll miss its activation. If you’d like something that has the same function but with less movement and more lights, there’s also a notification 3D cube made out of LEDs that’s sure to catch your eye as well. Continue reading “Popup Notification Dinosaur” →

The Science Of Landing On An Asteroid

October 16, 2018 by 17 Comments

Exploiting the resources of the rock-strewn expanse of space between Mars and the outer planets has been the stuff of science fiction for ages. There’s gold in them ‘thar space rocks, or diamonds, or platinum, or something that makes them attractive targets for capitalists and scientists alike. But before actually extracting the riches of the asteroid belt, stuck here as we are at the bottom of a very deep gravity well that’s very expensive to climb out of, we have to answer a few questions. Like, how does one rendezvous with an asteroid? What’s involved with maneuvering near a comparatively tiny celestial body? And most importantly, how exactly does one land on an asteroid and do any useful work?

Back in June, a spacecraft launched by the Japanese Aerospace Exploration Agency (JAXA) finally caught up to an asteroid named Ryugu after having chased it for the better part of four years. The Hayabusa2 was equipped to answer all those questions and more, and as it settled in close to the asteroid with a small fleet of robotic rovers on board, it was about to make history. Here’s how they managed to not only land on an asteroid, but how the rovers move around on the surface, and how they’ll return samples of the asteroid to Earth for study.

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The Incredible Judges Of The Hackaday Prize

October 15, 2018 by 1 Comment

The last challenge of The Hackaday Prize has ended. Over the past few months, we’ve gotten a sneak peek at over a thousand amazing projects, from Open Hardware to Human Computer Interfaces. This is a contest, though, and to decide the winner, we’re tapping some of the greats in the hardware world to judge these astonishing projects.

Below are just a preview of the judges in this year’s Hackaday Prize. In the next few weeks, we’ll be sending the judging sheets out to them, tallying the results, and in just under a month we’ll be announcing the winners of the Hackaday Prize at the Hackaday Superconference in Pasadena. This is not an event to be missed — not only are we going to hear some fantastic technical talks from the hardware greats, but we’re also going to see who will walk away with the Grand Prize of $50,000.


Sherry Huss

Sherry Huss is the former vice president of Maker Media, and oversees the publishing of Make Magazine and Maker Faires across the globe. Sherry is a major advocate of ‘all things maker’ in the global community, and her vision and passion for the maker movement was instrumental in growing the Make: brand within the maker ecosystem. Under her guidance, the largest Maker Faires, the Bay Area and World Maker Faire in New York, have grown from just a few thousand people in 2006 to events with over 200,000 attendees each year. Sherry is a giant in the Maker world, and an unending advocate of maker, DIY, and everyone who makes, whether that’s through wood, code, metal, solder, or fabric.

Anool Mahidharia

Anool is an electrical engineer, and works in Test & Measurement at Lumetronics. He’s part of WyoLum, an international group of hardware nerds who are consistently pumping out projects that push the limits of how blinky, glowey, and interesting a thing can be. They’re behind some projects you may have caught at random hacker meetups, and the creators of an absurd RGB LED cube that’s also a die. Anool is, by every account, an extremely capable hardware engineer, a longtime writer for Hackaday, and is constantly travelling the world presenting the latest developments in electronics to the public.

Danielle Applestone

Before founding Other Machine Co., now Bantam Tools, makers of tiny desktop milling machines that make fantastic circuit boards, Danielle Applestone worked with DARPA to develop high-precision machines that were effectively made out of kitchen cutting boards. HDPE, it turns out, is extraordinarily mechanically stable, cuts and machines easily, and can make very rigid components. Danielle spun this research out into the Othermill, an actual successful hardware startup. Danielle talked about this experience at the Hackaday Superconference, and we’re thrilled to have her on board judging other makers in their efforts to create the next big hardware thing.

Kwabena Agyeman

Kwab is one of the leading experts in computer vision and machine learning applications, and specializes in FPGA and Chip design. His greatest contribution to Open Hardware is the OpenMV, a platform for Computer Vision, ‘at the edge’, or basically a very high performance microcontroller and camera module on a single board, that’s running computer vision algorithms. This project began as a Hackaday Prize project that was then bootstrapped into a successful business. Formerly of Planet Labs where he spent his time pulling off Apollo 13-level hacks on space assets, Kwab is among the most successful designers in the world of Open Hardware.

These are just a few of the amazingly accomplished judges we have lined up to determine the winner of this year’s Hackaday Prize. The winner will be announced on November 3rd at the Hackaday Superconference. There are still tickets available, but if you can’t make it, don’t worry. We’re going to be live streaming everything, including the prize ceremony, where one team will walk away with the grand prize of $50,000. It’s not an event to miss.

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R3-14, The Personal Assistant Two Years In The Making

October 14, 2018 by 1 Comment

One of the great things about hacking together projects these days is how many powerful subsystems are readily available to reuse. [Sanjeet] took full advantage of a whole slate of reusable pieces when he built R3-14 — a personal assistant robot that you can see in action in the video below.

Many people started out in electronics building something simple like a crystal radio or an LED cube. But how far could you get if your projects had to begin at the most basic level, by drawing out copper wire, fabricating coils, capacitors, semiconductor devices, and batteries? Even if you know how to do all those things, it would take a lot of time, so there is no shame in using off-the-shelf components. By the same token, [Sanjeet] uses Google Assistant, 433 MHz RF transmitters, and a Raspberry Pi as components in this build. Along the way, he also contributed some reusable pieces himself, including an LED library for the PI and a library to allow Siri to control a Raspberry Pi.

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