Driving E-Paper Displays With Memory Limited MCUs

November 21, 2022 by Tom Nardi 20 Comments

It’s easy to become jaded by modern microcontrollers: for just a few bucks you can get a MCU that’s powerful enough to give a desktop computer from the early 90s a run for its money while packing in contemporary technology like WiFi and Bluetooth. For many projects we don’t even have to consider optimizing our code, because we aren’t even scratching the surface of what the hardware is capable of.

But sometimes you don’t have the luxury of using the latest-and-greatest chip, and have to play the hand you’re dealt. That’s when folks like [Larry Bank] really shine. In a recent write-up, he goes over his experiments with driving e-paper displays (specifically, salvaged electronic shelf labels) with 8-bit MCUs that on paper shouldn’t have the resources to run them.

The problem is that these displays generally expect to be handed a fully-formed image, which can easily exceed the free RAM on a low-end chip. For example, a 1-bit 128 x 128 image would consume 2 KB of RAM — more than four times the available memory on an ATtiny85.

As [Larry] explains, his alternate approach is to write data to the display in columns that are only one byte wide. Combined with his existing work with image decompression on constrained hardware, he’s able to rapidly draw out full-screen TIFF images using an Arduino UNO as demonstrated in the video after the break. He hopes the work will inspire others to experiment with what’s possible using the dinky MCUs you generally find in second-hand shelf labels.

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A Handy OSHW USB Cable Tester For Your Toolkit

November 20, 2022 by Tom Nardi 25 Comments

There’s no shame in admitting you’ve been burned by a cheapo USB cable — ever since some bean counter realized there was a few cents to be saved by producing “power only” USB cables, no hardware hacker has been safe. But with this simple tester from [Álvaro Prieto] in your arsenal, you’ll never be fooled again.

It’s about as straight-forward a design as possible, utilizing nothing more than a two dozen LEDs, their associated resistors, and a common CR2032 coin cell. Simply plugging both sides of your cable into the various flavors of USB connectors on the tester will complete the necessary circuits to light up the corresponding LEDs, instantly telling you how many intact wires are inside the cable. So whether you’re dealing with some shady cable that doesn’t have the full complement of conductors, or there’s some physical damage that’s severed a connection or two, you’ll know at a glance.

A sage warning for most of the devices we build.

Obviously the tester is designed primarily for the 24 pins you’ll find in a proper USB-C connector, but it’s completely backwards compatible with older cables and connectors. We appreciate that he even included the chunky Type B connector, which we’ve always been fond of thanks to its robustness compared to the more common Mini and Micro variants.

Keep in mind though that this tester will only show you if there’s a connection between two pins, it won’t verify how much power it can actually handle. For that, you’ll need some extra equipment.

ESP32 LED Eyes Help Keep Toddler In Bed

November 19, 2022 by Tom Nardi 14 Comments

We’ve seen a lot of custom clocks here at Hackaday, many of which have pushed the traditional definition of the timepiece to its absolute limit. But for all their wild designs, most of them do have something in common: they assume you can actually read a clock and understand the concept of time. But what if you’re developing a clock for a toddler who’s only just coming to terms with such heady ideas?

The answer, at least for [Riley Parish] is a set of 3D printed eyes that are illuminated with either yellow or green LEDs depending on whether or not it’s time to get out of bed. More than just the color of the light, the eye design (which is embedded into the rear of the front panel) switches between wide-open and tightly shut depending on the time of day.

Internally the device is very simple, with the 5 mm LEDs and their associated resistors connected directly to the digital out pins on an ESP32 development board. While the dual-core microcontroller is admittedly pretty overkill for flipping some LEDs every 12 hours or so, the firmware does at least pull the current time from NTP — plus the powerful MCU offers plenty of room to grow. A web front-end to configure the device or check its current status would only be a few more lines of code.

As it so happens, this isn’t the first toddler timepiece to grace these pages. Perhaps unsurprisingly, those previous examples also used changing color to help indicate the passage of time.

Hackaday Podcast 192: Supercon Was Awesome, How To Grind ICs And Make Your Own Telescope

November 11, 2022 by Tom Nardi 1 Comment

This week, Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi are still flying high on their post-Supercon buzz (and are a bit jet lagged) this week. We’ll start with some of the highlights from our long-awaited Pasadena meetup, and talk a bit about the winner of this year’s Hackaday Prize. Talk will then shift over to shaved down NES chips, radioactive Dungeons and Dragons gameplay, an impressive 3D printed telescope being developed by the community, and the end of the Slingbox. Stick around for a double dose of Dan Maloney, as we go over his twin treatises on dosimetry and the search for extraterrestrial life.

Download it, burn it on a floppy, and you’ll have it forever!

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Hackaday Prize 2022: Meet The Winners Of This Year’s Competition

November 5, 2022 by Tom Nardi 9 Comments

This year, the 2022 Hackaday Prize challenged hackers and makers in the open source community to develop projects which evoked the concepts of Sustainability, Resiliency, and Circularity — ideas which perhaps have never been more important. As humanity works to become better stewards to the only planet they can call home, everything we build (or rebuild) should reflect our desire to preserve our world for future generations.

Today, we’re excited to announce the projects that our panel of expert judges believe best exemplified this year’s theme and took home their share of the $50,000 USD in prize money.

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Plasma Channel Shows Off A Remarkably Stylish Fusor

October 27, 2022 by Tom Nardi 19 Comments

We’ve seen our fair share of Farnsworth–Hirsch fusors over the years — these high-voltage devices can get ions cooking to the point of achieving nuclear fusion even on a hobbyist’s budget, and even though they won’t solve the world’s energy problems, they certainly make for an impressive light show. While “simple” to build in the relative sense, the examples we’ve seen in the past have still been bulky contraptions supported by a cart full of complex gear befitting a nuclear reactor.

Which is why the fusor [Jay Bowles] recently completed is so impressive. As you can see in the latest Plasma Channel video which we’ve placed below the break, this desktop “star in a jar” not only features an incredibly low part count, but looks more like a movie prop than anything you’d expect to find in a physics lab. If you ever considered building a fusor of your own but were put off by the size and complexity of existing designs, you’ll definitely want to check this out.
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ERRF 22: Baby Belt Promises Infinite Z For Under $200

October 23, 2022 by Tom Nardi 20 Comments

Hackaday has been reporting on belt printers for around a decade now, since MakerBot released (and then quickly pulled) an automated build platform for their very first Cupcake printer. Turns out that not only has the concept been difficult to pull off from a technical perspective, but a murky patent situation made it tricky for anyone who wanted to bring their own versions to market. For a long time they seemed like the fusion reactors of desktop 3D printing — a technology that remains perennially just outside of our grasp.

But finally, things have changed. The software has matured, and there are now several commercial belt printers on the market. The trick now, as it once was for traditional desktop 3D printing, is to bring the costs down. Enter the Baby Belt, created by [Rob Mink]. This open-source belt printer relies on light-duty components and a largely 3D printed structure to get the price point down, though some will find its diminutive dimensions a bit too limiting…even if one of its axes is technically infinite.

If you’ve already got a printer and filament to burn, [Rob] is selling the part kit for just $130 USD. But even if you opt for the full ready-to-build kit, it will only set you back $180. Considering even the cheapest belt printers on the market now have a sticker price of more than $500, that’s an impressive accomplishment.

Of course, it’s hard to compare the Baby Belt with anything else on the market. For one thing, save for a few metal rods, its frame is made almost entirely from 3D-printed parts. Rather than the NEMA 17 stepper motors that are standard on even the cheapest of traditional desktop 3D printers, this little fellow is running on the dinky 28BYJ-48 steppers that you’d expect to find in a cheap toy. Then again, considering the printer only offers 85 x 86 mm in the X and Y axis, the structure and motors don’t exactly need to be top of the line.

What really sets this machine apart is the belt — while we’ve seen other makers go all out with their belt material, [Rob] has come up with an impressively low-tech solution. It’s a simple stack-up of construction paper, carpet tape, and fabric that you could probably put together with what you’ve got laying around the house right now.

Between that outer cloth layer and the printed frame, the Baby Belt offers a lot of room for customization, something which was on clear display at the 2022 East Coast RepRap Festival. The machines dotted several tables on the show floor, and you could tell their builders had a lot of fun making each one their own

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