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Hackaday Links: September 13, 2020

Like pretty much every other big conference, the Chaos Communication Conference is going virtual this year. What was supposed to be 37C3 has been rebranded as rC3, the remote Chaos Experience. It’s understandable, as a 17,000 person live event would have not only been illegal but a bit irresponsible in the current environment. The event appears to be a hybrid of small local events hosted in hackerspaces linked with streamed talks and a program of workshops and “online togetherness.” rC3 is slated to run in the week between Christmas and New Year, and it seems like a great way to wrap up 2020.

Speaking of remote conferences, don’t forget about our own Remoticon. While it won’t be quite the same as everyone getting together in sunny — historically, at least — Pasadena for a weekend of actual togetherness, it’s still going to be a great time. The event runs November 6 to 8; we’ve had a sneak peek at the list of proposed workshops and there’s some really cool stuff. Prepare to be dazzled, and make sure you keep up on the Remoticon announcements — you really don’t want to miss this.

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Transform Kicad Design To Patchwork For Isolation Routing

Tuning a desktop router and your board designs for isolation routing can be a bit tricky, with thin traces usually being the first victim. For simple prototype boards you usually don’t need tightly packed traces, you just want to isolate the nets. To do this with a minimum amount of routing, [Michael Schembri] created kicad-laser-min, a command-line utility that takes a Kicad PCB design and expands all the tracks and pads to their maximum possible width.

Laser scribed PCB with maximum track widths

The software takes one layer of the PCB layout, converts it to black and white, and then runs a C++ Voronoi algorithm on it to dilate each track and pad until it meets another expanding region. Each region is colourised, and OpenCV edge detection is used to produce the contours that need to be milled or etched. A contour following algorithm is then used to create the G-code. The header image shows the output of each step.

Full source code is available on GitHub. [Michael] has had good results with his own boards, which are scribed using a laser cutter before etching, but welcomes testing and feedback from other users. He has found that OpenCV doesn’t always completely close all the contours, but the gaps are usually smaller than the engraving width of his laser, so no shorts are created.

This is basically “Scribble style” prototyping with CAD and CNC tools. If you prefer scribe and etch, you might consider building a simple PCB shaker for faster etching. If you have a router but want to avoid the dust, you can use a carbide scribe to scratch out the tracks without needing to etch.

Making PCBs The Easy Way

Building a PCB at home can be fraught. If you’re etching, there are chemicals and the nuances of toner transfer. If you’re milling, getting the surface height just right, and not breaking those pointy little v-cutters is always a challenge. [Robin] has tips for both of these cases, and solves a lot of the common hassles by using a milling machine.

Whether he’s scraping away etch resist or entire copper isolation lines, [Robin] uses a non-spinning scratching tool instead of a v-bit: they’re more robust and cut every bit as well. He’s got tips for using FlatCam and KiCAD to make scratched-out traces. His registration system allows him to get double-sided boards with a minimum of hassle. And as a bonus, he’s doing some experimentation with embedding SMT parts inside the boards as well. Be sure that you check out his whole guide, or just watch the video embedded below.

We’re pretty sure you’ll pick up a trick or two, and maybe you’ll be convinced to bite the bullet and invest in a nice mill. If you’d like a more traditional take on PCB milling, try out our own [Adil Malik]’s guide.

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[Ben Krasnow] Rolls Old School Camera Out For Photolithography

In a time when cameras have been reduced to microchips, it’s ironic that the old view camera, with its bellows and black cloth draped over the viewscreen for focusing, endures as an icon for photography. Such technology appears dated and with no application in the modern world, but as [Ben Krasnow] shows us, an old view camera is just the thing when you want to make homemade microchips. (Video, embedded below.)

Granted, the photolithography process [Ben] demonstrates in the video below is quite a bit upstream from the creation of chips. But mastering the process on a larger scale is a step on the way. The idea is to create a high-resolution photograph of a pattern — [Ben] chose both a test pattern and, in a nod to the season, an IRS tax form — that can be used as a mask. The camera he chose is a 4×5 view camera, the kind with lens and film connected by adjustable bellows. He found that modifications were needed to keep the film fixed at the focal plane, so he added a vacuum port to the film pack to suck the film flat. Developing film has always been magical, and watching the latent images appear on the film under the red light of the darkroom really brings us back — we can practically smell the vinegary stop solution.

[Ben] also steps through the rest of the photolithography process — spin coating glass slides with photoresist, making a contact print of the negative under UV light, developing the print, and sputtering it with titanium. It’s a fascinating process, and the fact that [Ben] mentions both garage chip-maker [Sam Zeloof] and [Justin Atkin] from the Thought Emporium means that three of our favorite YouTube mad scientists are collaborating. The possibilities are endless.

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Vinyl Cut Your Way Into An Edge-Lit Glass Display

The chances are you’ve seen the myriad cheap copyright-infringing edge-lit acrylic displays from Chinese suppliers everywhere on the internet, and indeed, etching acrylic with a modest CNC laser cutter has become easily viable to a lot of us in more recent years. However, if you want to kick things up a notch, [Michael Vieau] shows us how to build a plaque from scratch using not acrylic, but rather etched glass to make the finished product look that much more professional.

There are a few different steps to this build and each one is beautifully detailed for anyone who wants to follow along. First, the electronics driving the WS2812 lights are designed from scratch based on an ATtiny microcontroller on a PCB designed in Fritzing, and the sources necessary for replicating those at home are all available on [Michael’s] GitHub. He even notes how he custom-built a pogo-pin header at the end of the USBASP programmer to be able to easily use the same ICSP pinout in future projects.

But since a lot of you are likely all too familiar with the ins and outs of your basic Arduino projects, you’ll be more interested in the next steps, detailing how he milled the solid wood base and etched the glass that fits onto it. The process is actually surprisingly simple, all you need is to mask out the design you want through the use of a vinyl cutter and then pouring some etching solution over it. [Michael] recommends double-etching the design for a crisper look, and putting everything together is just as simple with his fastener of choice: hot glue.

Much as there was an age when Nixie displays adorned every piece of equipment, it seems like ease of manufacture is veering us towards an age of edge-lit displays. From word clocks to pendants and badges, we’re delighted to see this style of decoration emerge, including in replacing Nixies themselves!

This Home-Etched ARM Dev Board Is A Work Of Art

One of the step changes in electronic construction at our level over the last ten or fifteen years has been the availability of cheap high-quality printed circuit boards. What used to cost hundreds of dollars is now essentially an impulse buy, allowing the most intricate of devices to be easily worked with. Many of us have put away our etching baths for good, often with a sigh of relief.

We’re pleased that [Riyas] hasn’t though, because they’ve etched an STM32 dev board that if we didn’t know otherwise we’d swear had been produced professionally. It sports a 176-pin variant of an STM32F4 on a single-sided board, seemingly without the annoying extra copper or lack-of-copper that we remember from home etching. We applaud the etching skill that went into it, and we’ll ignore the one or two boards that didn’t go entirely to plan. A coat of green solder mask and some tinning, and it looks for all the world as though it might have emerged from a commercial plant. All the board files are available to download along with firmware samples should you wish to try making one yourself, though we won’t blame you for ordering it from a board house instead.

It’s always nice to see that single board computers are not the sole preserve of manufacturers. If the RC2014 Micro doesn’t isn’t quite your style, there’s always the Blueberry Pi which features a considerably higher penguin quotient.

Homemade Integrated Circuits Hack Chat

Join us on Wednesday, August 14th at noon Pacific for the Homemade Integrated Circuits Hack Chat with Sam Zeloof!

While most of us are content to buy the chips we need to build our projects, there’s a small group of hackers more interested in making the chips themselves. What it takes the big guys a billion-dollar fab to accomplish, these hobbyists are doing with second-hand equipment, chemicals found in roach killers and rust removers, and a lot of determination to do what no DIYer has done before.

Sam Zeloof is one of this dedicated band, and we’ve been following his progress for years. While he was still in high school, he turned the family garage into a physics lab and turned out his first simple diodes. Later came a MOSFET, and eventually the Z1, a dual-differential amp chip that is the first IC produced by a hobbyist using photolithography.

Sam just completed his first year at Carnegie-Mellon, and he’s agreed to take some precious summer vacation time to host the Hack Chat. Join us as we learn all about the Z1, find out what improvements he’s made to his process, and see what’s next for him both at college and in his own lab.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, August 14 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.