Computer Vision For PCB Layout

One of the big problems with doing PCB layout is finding a suitable footprint for the components you want to use. Most tools have some library although — of course — some are better than others. You can often get by with using some generic footprint, too. That’s not handy for schematic layout, though, because you’ll have to remember what pin goes where. But if you can’t find what you are looking for SnapEDA is an interesting source of components available for many different layout tools. What really caught our eye though was a relatively new service they have that uses computer vision and OCR to generate schematic symbols directly from a data sheet. You can see it work in the video below.

The service seems to be tied to parts the database already knows about. and has a known footprint available. As you’ll see in the video, it will dig up the datasheet and let you select the pin table inside. The system does OCR on that part of the datasheet, lets you modify the result, and add anything that it missed.

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Scotty Allen’s PCB Fab Tour is Like Willy Wonka’s for Hardware Geeks

The availability of low-cost, insanely high-quality PCBs has really changed how we do electronics. Here at Hackaday we see people ditching home fabrication with increasing frequency, and going to small-run fab for their prototypes and projects. Today you can get a look at the types of factory processes that make that possible. [Scotty Allen] just published a (sponsored) tour of a PCB fab house that shows off the incredible machine tools and chemical baths that are never pondered by the world’s electronics consumers. If you have an appreciation PCBs, it’s a joy to follow a design through the process so take your coffee break and let this video roll.

Several parts of this will be very familiar. The photo-resist and etching process for 2-layer boards is more or less the same as it would be in your own workshop. Of course the panels are much larger than you’d ever try at home, and they’re not using a food storage container and homemade etchant. In fact the processes are by and large automated which makes sense considering the volume a factory like this is churning through. Even moving stacks of boards around the factory is show with automated trolleys.

Six headed PCB drilling machine (four heads in use here).

What we find most interesting about this tour is the multi-layer board process, the drilling machines, and the solder mask application. For boards that use more than two layers, the designs are built from the inside out, adding substrate and copper foil layers as they go. It’s neat to watch but we’re still left wondering how the inner layers are aligned with the outer. If you have insight on this please sound off in the comments below.

The drilling process isn’t so much a surprise as it is a marvel to see huge machines with six drill heads working on multiple boards at one time. It sure beats a Dremel drill press. The solder mask process is one that we don’t often see shown off. The ink for the mask is applied to the entire board and baked just to make it tacky. A photo process is then utilized which works much in the same way photoresist works for copper etching. Transparent film with patterns printed on it cures the solder mask that should stay, while the rest is washed away in the next step.

Boards continue through the process to get silk screen, surface treatment, and routing to separate individual boards from panels. Electrical testing is performed and the candy making PCB fab process is complete. From start to finish, seeing the consistency and speed of each step is very satisfying.

Looking to do a big run of boards? You may find [Brian Benchoff’s] panelization guide of interest.

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PCBs As Linear Motors

PCBs are exceptionally cheap now, and that means everyone gets to experiment with the careful application of copper traces on a fiberglass substrate. For his Hackaday Prize entry, [Carl] is putting coils on a PCB. What can you do with that? Build a motor, obviously. This isn’t any motor, though: it’s a linear motor. If you’ve ever wanted a maglev train on a PCB, this is the project for you.

This project is a slight extension of [Carl]’s other PCB motor project, the aptly named PCB Motor. For this project, [Carl] whipped up a small, circular PCB with a few very small coils embedded inside. With the addition of a bearing, a few 3D printed parts, and a few magnets, [Carl] was able to create a brushless motor that’s also a PCB. Is it powerful enough to use in a quadcopter? Probably not quite yet.

Like [Carl]’s earlier PCB motor, this linear PCB motor follows the same basic idea. The ‘track’, if you will, is simply a rectangular PCB loaded up with twelve coils, each of them using 5 mil space and trace, adding up to 140 turns. This is bigger than the coils used for the (circular) PCB motor, but that only means it can handle a bit more power.

As for the moving part of this motor, [Carl] is using a 3D printed slider with an N52 neodymium magnet embedded inside. All in all, it’s a simple device, but that’s not getting to the complexity of the drive circuit. We’re looking forward to the updates that will make this motor move, turning this into a great entry for The Hackaday Prize.

Ask Hackaday: What Color Are Your PCBs?

A decade ago, buying a custom-printed circuit board meant paying a fortune and possibly even using a board house’s proprietary software to design the PCB. Now, we all have powerful, independent tools to design circuit boards, and there are a hundred factories in China that will take your Gerbers and send you ten copies of your board for pennies per square inch. We are living in a golden age of printed circuit boards, and they come in a rainbow of colors. This raises the question: which color soldermask is most popular, which is most desirable, and why? Seeed Studio, a Chinese PCB house, recently ran a poll on the most popular colors of soldermask. This was compared to their actual sales data. Which PCB color is the most popular? It depends on who you ask, and how you ask it.
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Tiny $25 Spectrometer Aims to Identify Materials with Ease

Reflectance spectrometers work on a simple principle: different things reflect different wavelengths in different amounts, and because similar materials do this similarly, the measurements can be used as a kind of fingerprint or signature. By measuring how much of which wavelengths get absorbed or reflected by a thing and comparing to other signatures, it’s possible to identify what that thing is made of. This process depends heavily on how accurately measurements can be made, so the sensors are an important part.

[Kris Winer] aims to make this happen with the Compact, $25 Spectrometer entry for The 2018 Hackaday Prize. The project takes advantage of smaller and smarter spectral sensors to fit the essential bits onto a PCB that’s less than an inch square. If the sensors do the job as expected then that’s a big part of the functionality of a reflectance spectrometer contained in a PCB less than an inch square and under $25; definitely a feat we’re happy to see.

Tiny Sideways Tetris on a Business Card

Everyone recognizes Tetris, even when it’s tiny Tetris played sideways on a business card. [Michael Teeuw] designed these PCBs and they sport small OLED screens to display contact info. The Tetris game is actually a hidden easter egg; a long press on one of the buttons starts it up.

It turns out that getting a playable Tetris onto the ATtiny85 microcontroller was a challenge. Drawing lines and shapes is easy with resources like TinyOLED or Adafruit’s SSD1306 library, but to draw those realtime graphics onto the 128×32 OLED using that method requires a buffer size that wouldn’t fit the ATtiny85’s available RAM.

To solve this problem, [Michael] avoids the need for a screen buffer by calculating the data to be written to the OLED on the fly. In addition, the fact that the smallest possible element is a 4×4 pixel square reduces the overall memory needed to track the screen contents. As a result, the usual required chunk of memory to use as a screen buffer is avoided. [Michael] also detailed the PCB design and board assembly phases for those of you interested in the process of putting together the cards using a combination of hot air reflow and hand soldering.

PCB business cards showcase all kinds of cleverness. The Magic 8-Ball Business Card is refreshingly concise, and the project that became the Arduboy had milled cutouts to better fit components, keeping everything super slim.

One-key Keyboard is Exercise in Sub-millimeter Design

As [Glen] describes it, the only real goal in his decision to design his single-key USB keyboard was to see how small he could build a functional keyboard using a Cherry MX key switch, and every fraction of a millimeter counted. Making a one-key USB keyboard is one thing, but making it from scratch complete with form-fitting enclosure that’s easy to assemble required careful design, and luckily for all of us, [Glen] has documented it wonderfully. (Incidentally, Cherry MX switches come in a variety of qualities and features, the different models being identified by their color. [Glen] is using a Cherry MX Blue, common in keyboards due to its tactile bump and audible click.)

[Glen] steps though the design challenges of making a device where seemingly every detail counts, and explains problems and solutions from beginning to end. A PIC16F1459, a USB micro-B connector, and three capacitors are all that’s needed to implement USB 2.0, but a few other components including LED were added to help things along. The enclosure took some extra care, because not only is it necessary to fit the board and the mounted components, but other design considerations needed to be addressed such as the depth and angle of the countersink for the screws, seating depth and clearance around the USB connector, and taking into account the height of the overmold on the USB cable itself so that the small device actually rests on the enclosure, and not on any part of the cable’s molding. To top it off, it was also necessary to adhere to the some design rules for minimum feature size and wall thicknesses for the enclosure itself, which was SLS 3D printed in nylon.

PCB, enclosure, software, and bill of materials (for single and triple-key versions of the keyboard) are all documented and available in the project’s GitHub repository. [Glen] also highlights the possibility of using a light pipe to redirect the embedded LED to somewhere else on the enclosure; which recalls his earlier work in using 3D printing to make custom LED bar graphs.