A Bolt-On I2C Navigation Key for Your Next Project

We often talk about the advantages of modular hardware here at Hackaday; the ability to just order a few parts online, hook them up with some jumper wires, and move onto the software side of things is a monumental time saver when it comes to prototyping. So anytime we see a new module that’s going to save us time and aggravation down the road, we get a bit excited.

Today we present the very slick I2CNavKey developed by [Saimon], a turn-key interface solution for your builds that can’t quite get away with a couple toggle switches. It not only gives you a four-way directional pad with center button, but a rotary “wheel” like on the old iPods. All of which you can access easily and with a minimum of wiring thanks to the wonders of I2C.

But even that might be selling the module short. This isn’t just a couple of buttons on a breakout board, the I2CNavKey is powered by its own PIC16F18345 microcontroller and features three configurable GPIOs with PWM support (perfect for an RGB LED) plus 256 bytes of onboard EEPROM storage.

[Saimon] has released the entire project as open source hardware for your hacking pleasure, but you can also get them as ready-to-use modules on Tindie for $18 USD [Editor’s Note: Because of a typo we originally we left the 1 out of the price]. Whether you’re a paying customer or not, you get access to the project’s absolutely phenomenal documentation, including a nearly 30 page manual that contains everything you’d ever want to know about the I2CNavKey and how to integrate it into your project. If all hardware was documented with this level of dedication, the world would be a much nicer place for folks like us.

If you recognize the name, or perhaps the affinity for neat I2C-connected input devices, it’s probably because you’ve seen his very similar I2C rotary encoder on these pages previously, which was a finalist in our Open Hardware Design Challenge during the 2018 Hackaday Prize.

See What’s Inside Night Vision, And How To Build Your Own

[Nick Chen] shared some fascinating and useful details about building a AN/PVS-14 monocular night vision device from parts. It’s not cheap, but the build would be a simple one for most Hackaday readers, at least the ones who are residents of the USA. Since the PVS-14 is export controlled under the International Traffic in Arms Regulations (ITAR), parts are not sold outside of the US. Still, [Nick]’s illustrated build instructions provide a good look at what’s inside these rugged devices.

The build consists of purchasing a PVS-14 parts kit (or “housing kit”) which includes nearly everything except the image intensifier module, which must be purchased separately. Once all the parts are in hand, [Nick] explains how to assemble the pieces into a working unit.

The view through a blemished (or “blem”) image intensifier. Cheaper, and perfectly serviceable as long as the center is clear.

Since the image intensifier is by far the most expensive component, there is an opportunity to save money by shopping for what [Nick] calls “blem” units. These units are functional, but have blemishes or dead spots within the field of view. The good news it that this makes them cheaper, and [Nick] points out that as long as the center region of the tube is clear, they are perfectly serviceable.

How much can one save by building from parts? [Nick] says buying a complete PVS-14 with a Gen 3 tube (sensitive to 450-950 nm) can cost between $2500 to $4000. It’s expensive equipment, no doubt, but deals can be found on the parts. Housing kits can be had for well under $1000, and [Nick] has purchased serviceable image intensifiers for between $500 and $1000. He says searching for “blem tubes” can help zero in on deals.

Knowing the right terms for searching is half the battle, and along with his build instructions (and a chunk of cash) a curious hacker would have all they need to make their own. Heck, build two because the PVS-14 is designed such that two units can be combined to make a binocular unit! Not ready to drop that kind of cash? Check out OpenScope, the open source digital night vision tool.

Vintage Print Processor Fixed with 3D Printing

If you don’t know what a print processor is, don’t feel bad. There’s precious few people out there still running home darkrooms, and the equipment used for DIY film development is about as niche as it gets today. For those looking to put together their own darkroom in 2019, buying second hand hardware and figuring out how to fix it on your own is the name of the game, as [Austin Robert Hermann] found out when he recently purchased a Durst Printo Print Processor on eBay.

The auction said the hardware was in working order, but despite the fact that nobody would ever lie on the Internet, it ended up being in quite poor condition. Many of the gears in the machine were broken, and some were simply missing. The company no longer supports these 1990’s era machines, and the replacement parts available online were predictably expensive. [Austin] determined his best course of action was to try his hand at modeling the necessary gears and having them 3D printed; two things he had no previous experience with.

Luckily for [Austin], many of the gears in the Printo appeared to be identical. That meant he had several intact examples to base his 3D models on, and with some educated guesses, was able to determine what the missing gears would have looked like. Coming from an animation background, he ended up using Cinema 4D to model his replacement parts; which certainly wouldn’t have been our first choice, but there’s something to be said for using what you’re comfortable with. Software selection not withstanding, he was able to produce some valid STLs which he had printed locally in PLA using an online service.

Interestingly, this is a story we’ve seen play out several times already. Gears break and wear down, and for vintage hardware, that can be a serious problem. But if you’ve got a couple intact gears to go by, producing replacements even on an entry level desktop 3D printer is now a viable option to keep these classic machines running.

Making The World’s Fastest 555 Timer, Or Using A Modern IC Version

If you’re not familiar with the 555 timer, suffice it to say that this versatile integrated circuit is probably the most successful ever designed, and has been used in countless designs, many of which fall very far afield from the original intent. From its introduction, the legendary 555 has found favor both with professional designers and hobbyists, and continues to be used in designs from both camps. New versions of the IC are still being cranked out, and discrete versions are built for fun, a temptation I just couldn’t resist after starting this article.

If you think all 555s are the same, think again. Today, a number of manufacturers continue to produce the 555 in the original bipolar formulation as well as lower-power CMOS. While the metal can version is no longer available, the DIP-8 is still around, as are new surface-mount packages all the way down to the chip-scale. Some vendors have also started making simplified variants to reduce the pinout. Finally, you can assemble your own version from a few parts if you need something the commercial offerings won’t do, or just want a fun weekend project. In my case, I came up with what is probably the fastest 555-alike around, although I spared little expense in doing so.

Follow along for a tour of the current state of the 555, and maybe get inspired to design something entirely new with this most versatile of parts.

Continue reading “Making The World’s Fastest 555 Timer, Or Using A Modern IC Version”

This Vintage Op-Amp Opens A Fascinating Window Into Semiconductor History

We have covered enough of the work of [Ken Shirriff] on these pages to know that when he publishes something, it will be a fascinating read and work of the highest quality. And so it is with his latest, a very unusual op-amp on which he performs his usual reverse engineering. Not only does it lead us directly to some of the seminal figures in the early years of the semiconductor industry, it turns out to have been a component manufactured to a NASA specification and of which there is an example on the Moon.

The metal can revealed a hybrid circuit when the lid was removed, one in which individual transistors were wired together with a single block containing a group of thin-film resistors. At the start of the 1960s the height of consumer electronics would have been your domestic TV which would have been an all-tube affair, so while it sounds archaic this would truly have been a space-age piece of technology. The designer is revealed as the legendary [Bob Pease], and the transistors take us back to the semiconductor physicist [Jean Hoerni], inventor of the planar transistor and one of the famous eight defectors from Shockley Semiconductor in the 1950s who kick-started the semiconductor boom.

The op-amp itself is a relatively simple design without the compensation capacitor you might expect in a modern device, but what makes it unusual for its time is the use of [Hoerni]’s planar JFETs at its input. [Ken]’s analysis is as usual extremely thorough, and the bit of Silicon Valley history it gives us is the icing on the cake.

If you have a thirst for ancient op-amps, you might like our look at the first commercially available fully-integrated design, the Fairchild μA702.

E-Ink Price Tags Fall Off Store Shelves Onto Your Workbench

There’s always a magic moment for our community in the lifecycle of any piece of technology: the point at which it first becomes available for pennies on the surplus market. Something which could previously be had only at a price is rendered down to mere pennies, and we are free to hack to our heart’s content.

Such a moment came for [Aaron Christophel] when he bought a quantity of used e-ink price tags (German, Google Translate link) that had formerly graced the shelves of a supermarket. A pile of readily hackable e-ink displays lay before him, so he set to work.

Cracking them open he found the display itself as well as a PCB with its own microcontroller, but he soon identified it as compatible with a WaveShare module for which he had data. Since its interface was thus identified as SPI he could desolder the unknown CPU and break out the pins for an Arduino or other board. The display itself turned out to be a custom model with a few quirks for price tags, it had a black border that could be enabled, and for some reason it appeared as a two-colour red-and-black model in which its black pixels responded as though they were the red channel. He has a quick overview video that we’ve placed below the break.

These displays have started appearing in our community, not least in electronic conference badges. This source of cheap components from the surplus market makes them ever more accessible, and we look forward to the projects that will come from them.

Continue reading “E-Ink Price Tags Fall Off Store Shelves Onto Your Workbench”

Get Organized With This Raspberry Pi E-Ink Calendar

Like many hackers, we love e-ink. There’s something mesmerizing and decidedly futuristic about the way the images shift around and reconstitute themselves. Like something from Harry Potter, but that you can buy on Alibaba instead of from a shop in Diagon Alley. But as anyone who’s used the technology can tell you, the low refresh rate of an e-ink screen limits its potential applications. It works great for reading books, but beyond that its struggled to find its niche in a world of cheap LCDs.

But [Zonglin Li] has recently wrapped up a project which shows that e-ink has at least one more use case: personal calendars. You can get way with only updating the screen once a day so the refresh rate won’t matter, and the rest of the time it’s going to be static anyway so you might as well enjoy the energy savings of leaving the screen off. With a Raspberry Pi behind the scenes pulling data from the Internet, it can populate the calendar with everything from your personal schedule to when your favorite podcast drops.

In practice, [Zonglin] is actually updating the display every hour as he’s included the current weather conditions on the top left of the screen, but even still, this is a perfect application for the very unique properties of e-ink displays. The display is a 7.5 inch 640×384 model from Waveshare that retails for about $50 USD, so between the display, the Raspberry Pi, and something to put it all in (here, a picture frame) this is a pretty cheap build compared to some of the large format e-ink displays out there.

The software side is written in Python 3, and [Zonglin] has documented how others can easily plug in their own information so it can pull schedule data from Google Calendar and local conditions from Open Weather Map. The MIT licensed source code is also very well organized and commented, so this could serve as an excellent base if you’re looking to create a more comprehensive e-ink home information display.

If this seems a little too pedestrian for your tastes, you could always put together an e-ink movie player, a surprisingly functional Linux terminal, or a very slick ESP8266-based name tag. If you’ve got the better part of $1K USD and don’t know what to do with it, you could even get an e-ink license plate.