A Mega-Tiny Arduino

Integrated circuits, chipsets, memory modules, and all kinds of other transistor-based technology continues to get smaller, cheaper, and more energy efficient as time moves on. Not only are the components themselves smaller, but their supporting infrastructure is as well. Computers like the Raspberry Pi are about the size of a credit card and have computing power on the order of full-sized PCs from a few decades ago. The Arduino is no exception to this trend, either, and this new dev board called the Epi 32U4 might be the smallest ATmega platform we’ve seen so far.

As the name suggests, the board is based around the ATmega32U4 which is somewhat unique among Atmel chips in that it includes support for USB within the chip itself rather than relying on external translating circuitry. This makes it an excellent choice for any project which involves sending keyboard, mouse, or other peripheral information to a computer. This goes a few steps further with eliminating “bloat” compared to other boards, too — there’s no on-board voltage regulator, and just a single LEDs on pin 13.

One of the other features this board boasts over other small form factor boards is on-board USB-C, which is definitely a perk as more and more devices switch away from the various forms of older USB-type plugs. The project’s specifications are also available on this GitHub page for anyone that wants to produce their own. And, if you don’t have a 32U4 on hand and still want to build a keyboard project, it’s possible to get some other Arduinos to support these features but it’ll take a little more work.

Thanks to [Rasmus L] for the tip!

Lisp Runs This Microcontroller Pendant

As a programming language, Lisp has been around longer than any other active language except for Fortran. To anyone who regularly uses it, it’s easy to see why: the language allows for new syntax and macros to be created fluidly, which makes it easy to adapt it to new situations, like running it on a modern Atmel microcontroller to control the LEDs on this star pendant.

The pendant has simple enough hardware — six LEDs arranged around the points of the star, all being driven by a small ATtiny3227 operating from a coin cell battery. This isn’t especially spectacular on it’s own, but this particular microcontroller is running an integer version of a custom-built Lisp interpreter called uLisp. The project’s creator did this simply because of the whimsy involved in running a high-level programming language on one of the smallest microcontrollers around that would actually support the limited functionality of this version of Lisp. This implementation does stretch the memory and processing capabilities of the microcontroller quite a bit, but with some concessions, it’s able to run everything without issue.

As far as this project goes, it’s impressive if for nothing other than the ‘I climbed the mountain because it was there’ attitude. We appreciate all kinds of projects in that same vein, like this Arduino competitor which supports a programming language with only eight commands, or this drone which can carry a human.

Showing a new generation ATTiny on an SMD breakout plugged into a breadboard, being programmed

Come Learn About New ATtiny Generations

As the chip shortage hit, a lot of the familiar ATtiny chips have become unavailable and overpriced, and it mostly stayed the same since then. If you ever searched for “ATtiny” on your favourite electronics component retailer website, however, you’d notice that there’s quite a few ATtiny chips in stock most of the time – just that they’re from a much newer generation than we commonly see, with incompatible pinouts, slightly different architecture and longer model numbers like 412 and 3227. [David Johnson-Davies] from [technoblogy] is here to clarify things, and provide a summary of what the new ATtiny generations have to offer.

In 2019, he posted about 0- and 1-series ATtiny chips, comparing them to the ATtiny series we knew, decyphering the part numbering scheme for us, and providing a comparison table. Now, he’s returned to tell us about the 2- series ATtiny chips, merging the comparison tables together so that you can quickly evaluate available parts by their ROM/RAM size and the SMD package used. He also describes which peripherals are available on which series, as well as nuances in peripheral operation between the three generations. In the end, he reminds us of a simple way to program all these new parts – as it stands, you only need a USB-UART adapter and a 4.7K resistor.

Over the last decades, we’ve seen plenty of inspiring ATtiny projects – squeezing out everything we could out of 5 GPIOs, or slightly more for larger-package ATtiny chips. [David] has been setting an example for us, bringing projects like this function generator, this continuity tester, or an IR receiver with an OLED screen for diagnostics – all with an ATtiny85. It’s not the just pin count that’s a constraint, but the RAM and flash amounts as well – nevertheless, people have fit machine learning and an entire graphics stack into these chips before. If you’re stuck at home unable to do anything, like many of us were during lockdowns, you can always breadboard an ATtiny and see just how much you can get done with it.

To Turn An ATtiny817 Into A 150MHz Counter, First Throw Out The Spec Sheet

One generally reads a data sheet in one of two ways. The first is to take every spec at face value, figuring that the engineers have taken everything into account and presented each number as the absolute limit that will prevent the Magic Smoke from escaping. The other way is to throw out the data sheet and just try whatever you want, figuring that the engineers played it as safely as possible.

The latter case seems to have been the motivation behind pushing an ATtiny way, WAY beyond what the spec sheet says is possible. According to [SM6VFZ], the specs on the ATtiny817 show that the 12-bit timer/counter D (TCD) should be limited to a measly 32 MHz maximum frequency, above which one is supposed to employ the counter’s internal prescaler. But by using a 10-MHz precision frequency generator as an external clock, [SM6VFZ] found that inputs up to slightly above 151 MHz were countable with 1-Hz precision. Above that point, things started to drift, but that’s still pretty great performance from something cobbled together on an eval board in a decidedly suboptimal way.

We’d imagine this result could lead to some interesting projects, since the undocumented limit for this timer puts it well within range of multiple amateur radio allocations. Even if it doesn’t prove useful, that’s OK — just seeing how far things can be pushed is cool too. And it’s not like this is the first time we’ve caught [SM6VFZ] persuading an ATtiny to do unusual things, either.

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Hackaday Links: February 27, 2022

If there’s one thing that can trigger people, it’s the printer racket. Printer manufacturers who put DRM-like features into their consumables are rightly viewed as Satan’s spawn, and while these monsters have been content so far to only put digital rights management features into their ink and toner cartridges, they appear to now have their rapacious gaze set on print media too. At least according to the good folks over at the Electronic Frontier Foundation, who claim that Dymo’s latest generation of label printers will have RFID tags in the label cartridges, apparently to prevent consumers from buying non-Dymo media. The company doesn’t bill it as a way to lock you into their exorbitantly priced consumables, of course; rather, this is an exciting new feature that’s called “Automatic Label Recognition,” which keeps track of what labels are installed and how many are left. Of course, this is just red meat to people like us, and we fully expect to see workarounds in the not-to-distant future.

Continue reading “Hackaday Links: February 27, 2022”

Tiny Operating System For Tiny Computer

Before the World Wide Web became ubiquitous as the de facto way to access electronic information, there were many other ways of retrieving information online. One of the most successful of these was Minitel, a French videotex service that lasted from 1980 all the way until 2012. But just because the service has been deactivated doesn’t mean its hardware can’t be used for modern builds like this Arduino-based operating system. (Google Translate from French)

Called ZARDOS, the operating system is built to run on an Arduino MEGA although a smaller version is available for the Uno. The Arduino is connected by a serial cable to the Minitel terminal. It can take input from a keyboard and PS/2 mouse and displays video on the terminal screen with the same cable. There is functionality built-in for accessing data on a cartridge system based on SD cards which greatly expands the limited capabilities of the Atmel chip as well, and there is also support for a speaker and a Videotex printer.

Even though the build uses a modern microcontroller, it gives us flashbacks to pre-WWW days with its retro terminal. All of the code is available on the project site for anyone looking to build an Arduino-based operating system, although it will take a little bit of hardware hacking to build a Minitel terminal like this. Either way, it’s a great way to revive some antique French hardware similar to a build we’ve seen which converts one into a Linux terminal.

Thanks to [troisieme_type] for the tip!

Squeezing Every Bit From An ATMega

While the ATMega328 is “mega” for a microcontroller, it’s still a fairly limited platform. It has plenty of I/O and working memory for most tasks, but this Battleship game that [thorlancaster328] has put together really stretches the capabilities of this tiny chip. Normally a Battleship game wouldn’t be that complicated, but this one has audio, an LED display, and can also play a fine rendition of Nyan Cat to boot, which really puts the Atmel chip through its paces.

The audio is played through a 512-byte buffer and an interrupt triggers the microcontroller when to fill the buffer while it works on the other processes. The 12×12 LED display is also fed through a shift register triggered by the same interrupt as the audio, and since the build uses so many shift registers the microcontroller can actually output four separate displays (two players, each with a dispaly for shots and one for ships). It will also eventually support a player-vs-computer mode for the battleship game, and also has a mode where it plays Nyan cat just to demonstrate its own capabilities.

We’re pretty impressed with the amount of work this small microcontroller is doing, largely thanks to code optimization from its creator [thorlancaster328]. If there’s enough interest he also says he will provide the source code too. Until then, be sure to check out this other way of pushing a small microcontroller to its limits.

Thanks to [Thinkerer] for the tip!