Thinnest Keyboard Uses Cherry DIY Doubleshot Method

May 10, 2022 by Kristina Panos 24 Comments

As with any other community, it takes all kinds to make the keyboard world go ’round. Some like them thicc — more backing for the clacking and all — but some like them sleek and prefer the slimmest possible keyboard. For now and the foreseeable future, the go-to method for making whisper-thin keebs is to use Kailh Choc switches, because that’s about all that’s out there.

But chocs aren’t for everyone, and there are plenty of die-hard Cherry fans out there that want it both ways. Being one among them, [Khmel] set about designing the lowest-profile possible keyboard (and caps) that uses standard Cherry-sized keyswitches. Shut up and take your money? Well, okay, but the case and keycap files are all available on Thingiverse, so.

The whole video is great, and at less than 2½ minutes long, it’s definitely worth your time. There are a few little gems of wisdom sprinkled throughout, like printing keycaps standing up on their backsides (like where they would have a little flash dot if they were factory-molded). This gives them a nice texture thanks to the layer lines. But the real reason we’re here today is this DIY method for making doubleshot keycaps with little fuss that [Khmel] just tosses out there toward the end.

Trust us, there’s a piece of glass there.

Traditionally, doubleshot keycaps are made with two layers of plastic — one for the legend, and one for the rest. This produces a quite durable keycap and (used to be the norm), but the expensive process gave way to laser-etched and pad-printed keycap legends in the ’90s. [Khmel] was able to fake the look by printing legends at 0.25 layer height and then fusing each one to its respective keycap by laying a thin piece of glass (think microscope slide) on top and applying a soldering iron for a few seconds. Classy!

Tweezing tiny legends not really your kind of tedium? Here’s a method for DIY waterslide decals instead.

Continue reading “Thinnest Keyboard Uses Cherry DIY Doubleshot Method” →

A vape pen, broken into parts, all laid out on a cutting mat

2022 Hackaday Prize: Disposable Vape Pens Turned Project Parts

May 5, 2022 by Arya Voronova 49 Comments

Disposable vape pens, a sub-genre of electronic cigarettes, have been a fad for a few years now – they’re small self-contained devices with a rechargeable battery and some vape liquid inside. As the battery discharges and the liquid runs out, the entire vape pen is typically thrown out. [Dimitar] wants to change that, however, and teaches us how to reuse as much of the vape pen as possible — as yet another underappreciated source for parts we can use in our projects.

In an extensive worklog, he breaks down and documents a vape pen’s inner workings, coupled with a video we’ve placed below the break showing ways to disassemble them. In these, he shows how we can reuse the casing and the plastic parts, should any of us be interested in a project that happens to fit the e-cig form factor. Attention is paid to the sensor that triggers the evaporation — it may look like a microphone, but is actually a purpose-built pressure-sensor with a high-side switch! He tears into one of these in a separate video, showing how to reuse it as a capacitive touch controller. He also aiming to assemble a small database of related resources on GitHub, currently, hosting the files for the protection circuit he developed as part of his recommendations for safely reusing vape pen Li-ion batteries.

[Dimitar]’s journey is ongoing, and we can’t wait to see some fun uses for these components that he will certainly stumble upon on his way! For instance, here’s a hacker using an e-cig battery to power a pair of RGB LED-adorned sunglasses, replacing the AAAA battery they originally came with. We’ve seen hackers make guides on reusing each and every part of microwave ovens, printers and laptops, and we ourselves have talked about reusing ATX power supplies and computer mice.

Continue reading “2022 Hackaday Prize: Disposable Vape Pens Turned Project Parts” →

Four jumper wires with white heatshrink on them, labelled VCC, SCL, SDA and GND

The Connector Zoo: I2C Ecosystems

May 4, 2022 by Arya Voronova 56 Comments

I2C is a wonderful interface. With four wires and only two GPIOs, you can connect a whole lot of sensors and devices – in parallel, at that! You will see I2C used basically everywhere, in every phone, laptop, desktop, and any device with more than a few ICs inside of it – and most microcontrollers have I2C support baked into their hardware. As a result, there’s a myriad of interesting and useful devices you can use I2C with. Occasionally, maker-facing companies create plug-and-play interfaces for the I2C device breakouts they produce, with standardized pinouts and connectors.

Following a standard pinout is way better than inventing your own, and your experience with inconsistent pin header pinouts on generic I2C modules from China will surely reflect that. Wouldn’t it be wonderful if you could just plug a single I2C-carrying connector into an MPU9050, MLX90614 or HMC5883L breakout you bought for a few dollars, as opposed to the usual hurdle of looking at the module’s silkscreen, soldering pin headers onto it and carefully arranging female headers onto the correct pins?

As with any standard, when it comes to I2C-on-a-connector conventions, you would correctly guess that there’s more than one, and they all have their pros and cons. There aren’t quite fifteen, but there’s definitely six-and-a-half! They’re mostly inter-compatible, and making use of them means that you can access some pretty powerful peripherals easily. Let’s start with the two ecosystems that only have minor differences, and that you’ll encounter the most! Continue reading “The Connector Zoo: I2C Ecosystems” →

A Great Resource For The Would-Be Pinball Machine Builder

April 29, 2022 by Dave Rowntree 12 Comments

Those of us beyond a certain age will very likely have some fond memories of many an hour spent and pocket money devoured feeding the local arcade pinball machine. At one time they seemed to be pretty much everywhere, but sadly, these days they seem to have largely fallen out of favour and are becoming more of speciality to be specifically sought out. Apart from a few random ones turning up — there’s a fun Frankenstein-themed machine in the Mary Shelley Museum in Bath, England — a trip to a local amusement arcade is often pretty disappointing, with modern arcade machines just not quite scratching that itch anymore, if you ask us. So what’s an old-school hacker to do, but learn how to build a machine from scratch, just the way we want it? A great resource for this is the excellent Pinball Makers site, which shows quite a few different platforms to build upon and a whole ton of resources and guides to help you along the way.

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Edible Electronics Let Us Hear The Lamentations Of The Chocolate Bunnies

April 19, 2022 by Kristina Panos 12 Comments

Yet another Day of the Chocolate Bunnies has passed by, and what did you do to mark the occasion? You likely kicked back and relaxed, surrounded by whatever you gave up for Lent, but good for you if you mixed chocolate and electronics like [Repeated Failure] did. They created a completely edible chocolate Easter bunny that screams when bitten.

So obviously, the hardest part is figuring out something to build the circuit with that is both conductive and safe to eat. [Repeated Failure] spent a lot of time with carbon oleogel paste, which is made from natural oils and waxes. Not only was it less conductive than [Repeated Failure]’s skin, it came out pitch black and tasted like nothing, which kind of a bonus, when you think about it.

Then came the cake paint, which [Repeated Failure] laced with trace amounts of silver powder. While that worked somewhat better, a successful circuit would have likely required near-fatal amounts of the stuff. Yikes!

The winner turned out to be edible silver leaf, which is like gold leaf but cheaper. Ever had Goldschläger? Gold leaf is what’s suspended inside. The really nice thing about silver leaf is that it comes in thin sheets and can easily be cut into circuit traces with scissors and connected to I/O pins with copper tape. Be sure to check it out after the break, including [Repeated Failure]’s friend’s reaction to innocently biting the chocolate bunny’s ears off, as one tends to do first.

Think you’d rather hear plants giggle? Sure, it sounds cute, but it’s actually kind of creepy.

Continue reading “Edible Electronics Let Us Hear The Lamentations Of The Chocolate Bunnies” →

Best Ways To Make PCB Breakaway Tabs, Revealed

April 9, 2022 by Donald Papp 20 Comments

Most of us are familiar with the concept of producing PCBs in a panel, and snapping them apart afterwards. V-grooves that go most of the way through a PCB are one way to go about this, but a line of perforations along which to snap a tab is another. But what’s the best size and spacing of holes to use? Sparkfun’s [Nick Poole] spent some $400 on PCBs to get some solid answers by snapping each of them apart, and judging the results.

The nice thing about creating a perforation line (or “mouse bites”) is that drill hits are a very normal thing in PCB production, which makes creating this kind of breakaway tab a very straightforward and flexible method. However, it can be tricky to get results that are just right. Too sturdy, and breaking apart is a hassle. Too weak, and the board may break or twist before its time. On top of that, edges must also break cleanly. We’ve covered panelizing PCBs in this way before, but this is the first time we’ve seen someone seriously look into how to create optimal breakaway tabs.

Placing holes tangent to the board edge (as shown above) isn’t the prettiest, but keeps PCB edges free from protrusions. This is best for boards that are rail-mounted, or have tight enclosures.

Data on designing mouse bites was sparse and a bit inconsistent, so [Nick] decided to figure it out empirically and share the results. The full details are available in Building a Better Mousebite (PDF download) but the essence of the recommendations are: 0.015″ unplated holes, spaced 0.025″ apart (center-to-center), tabs a maximum of 0.118″ wide (so as to be compatible with depanelizing tools), and holes that extend into the corners of the breakaway tab to avoid sharp edges. Holes should be placed slightly differently depending on whether one wishes to optimize the cosmetic appearance versus the physical smoothness of the board edge, but those numbers are the core of the guidelines.

To fine tune, [Nick] suggests increasing the spacing between holes to add strength, or just adding additional tabs. What about thickness of PCB? [Nick] tested boards both 0.8 mm and 1.6 mm thick, and while different amounts of torque were needed to snap the boards apart, things still worked as expected regardless of PCB thickness.

When it comes down to it, the best numbers will ultimately be the ones that your process or fab house can most efficiently handle, but [Nick]’s numbers should not steer anyone wrong, and it’s fantastic to see this kind of work go into refining such a common PCB feature.

Hacker Dictionary: RS-485 Will Go The Distance

April 5, 2022 by Arya Voronova 59 Comments

RS485 is a communication standard that should be part of the advanced hardware hacker’s arsenal; it’s not commonly encountered, but powerful exactly when you need it. It’s a physical layer interface for wired communications that uses a single differential pair for noise immunity, has good long-distance properties, and allows many connections to a single bus. Because of that, you will encounter it in security systems and even cameras, wired sensor networks, DMX512 lighting and all sorts of industrial electronics. For our hobbyist goals, you can absolutely use RS485 to build your home (or room) automation system, or a relatively large robot – without all those worries that wireless brings.

The name might remind you of RS232, and that’s because both RS232 and RS485 are standards that come from EIA (Electronics Industries Alliance). It also might remind you of RS422, if you’ve ever seen this name mentioned online – RS422 and RS485 are closely intertwined, sharing most of the physical layer, and I’ll show how exactly they relate. Continue reading “Hacker Dictionary: RS-485 Will Go The Distance” →