This PCB Business Card is Logically Different

Having seen a number of PCB business cards [Will] decided to go against the more popular choice of a micro-controller based design and show some character with a logic based finite state machine. [Will] uses a single 7-segment display to scroll through the letters of his name with a state machine that outputs the desired combination of 1’s and 0’s to the LED display each time the tactile button is pushed.

[Will] uses a 4-bit counter made up of D Flip-Flops for the clock signal as a conditional input to 6 of the 4-input AND gates. He doesn’t go into the painful details of displaying each character through the process (thankfully) but he does mention that he uses the Quine-McCluskey technique for reduction instead of Boolean algebra. Since his name is 11 characters long and the 4-bit binary counter goes from 0000 to 1111 leaving 5 more pushes of the button before rolling the count back to 0000, during which time the display is left blank. [Will] kindly includes the eagle and Gerber files for your downloading pleasure over at his blog if you’re interested in getting a little deeper into the design.

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The many iterations of [Joe’s] PCB business card

[Joe Colosimo] is putting on a show with his PCB business card project. The idea isn’t new, but his goal is to keep it simple and undercut the cost of all other PCB cards he’s seen. This is the third generation of the board design, and he’s just waiting on some solder mask solution before he tries running it through the reflow oven.

The first two prototypes used some through-hole parts. Notably, the battery was to be positioned in a circular cut-out and held in place by a metal strap and some bare wires. But he couldn’t quite get it to work right so this design will transition to a surface-mount strap for one side, and the large circular pad for the other. At each corner of the board there is a footprint for an LED. He tried milling holes in the board to edge-light the substrate. Now he just mounts the LED upside down to give the board a blue glow. The LEDs are driven by an ATtiny10 microcontroller which takes input from the touch sensor array at the bottom right.

He etched a QR code on the board which seems to work better than the milled QR experiments we saw back in April. The link at the top point’s to [Joe’s] main page on the card. Don’t forget to follow the links at the bottom which cover each part of the development more in-depth.

[Thanks Skitchin]

Use All that Extra Space with PCB Panelization

Anyone who’s made a PCB has encountered the conundrum of having to pay for space that you don’t use… for instance, designing a round PCB and seeing the corners go to waste. The solution? Smaller boards added to the blank spots.

One logical stumbling block might be that you simply don’t have a small PCB design ready to go. Latvian hacker [Arsenijs] created a resource of small PCBs that can be dropped into those blank spots, as well as a tutorial on how to combine the gerbers into a single panel.

Great minds think alike, and this guide is following hot on the heels of [Brian Benchoff’s] article on panelization. They’re both a great read. It’s interesting to think that not long ago we would see multiple guides on home etching boards and now we’ve climbed the production ladder to guides that help better utilize PCB fab houses. Neat!

This project seems a logical spinoff of [Arsenijs]’s ZeroPhone Pi smartphone project, a finalist for the 2017 Hackaday Prize that makes a low-cost phone using a stack of PCBs. One imagines that while prototyping the phone [Arsenijs] ended up with a lot of wasted space! Fill that up with smaller designs like breakouts, or decorative items like a hackerspace business card. If you’re looking for small PCBs you can find a few in the files area of the project on Otherwise, you can share yours and [Arsenijs] will add them.

Roll Your Own 64GB SD Card From An EMMC Chip

It’s well-known that buying Flash storage devices from cheap online retailers is fraught with danger. Stories abound of multi-gigabyte drives that turn out to be multi-megabyte ones engineered to falsely report their capacity. So when [Jason Gin] found a source of 64GB Toshiba eMMC chips for only $6 per device he bought a few, but was prepared for disappointment.

To test them, he decided to use an SD card interface. There are minor differences between eMMC and SD, but the interfaces are electrically the same and in most cases an SD controller will happily do business with an eMMC. It was not however an easy task to connect the two — these eMMCs were in BGA packages, hardly the easiest ones to work with. He resorted to dead-bug soldering the relevant interface wires to SD lines, and connecting up his computer.

His first attempt was something of a failure, wiring the chip to the PCB of a cheap USB-to-SD adaptor. This did not put him off though, he followed it up by cracking open a very old 2GB SD card that contained a PCB instead of being potted, and soldering his eMMC in place of its Flash and controller. This even fit in the original SD housing, and met with success when plugged into more reliable SD card readers. He was thus able to confirm the capacity of his chips.

His blog post is worth a read for more than just the very fine soldering involved. He takes us through some of the intricacies of SD interfacing, as well as talking at length about the decoupling and termination required to make a reliable connection. We particularly like his use of an area of unconnected BGA balls as prototyping space for decouplers.

If you marvel at the exceptional dexterity required for hand BGA work, we’ve a couple of other treats for you. There is this TI infra-red sensor BGA soldered to a piece of stripboard, and this wafer-level chip package soldered to an SOIC prototyping board.

FR4 Machine Shield Is A CNC Milling Machine From FR4 PCB

The people behind the PocketNC heard you like CNC PCB mills, so they milled you a PCB mill out of PCB. They announced their surprising new open source hardware product, a pocket sized 3-axis CNC machine entirely made out of FR4 PCB material, aptly named “FR4 Machine Shield”, at this year’s Bay Area Maker Faire.

UPDATE: The FR4 Machine Shield is now on Kickstarter

fr4_thumbWe know the concept from quadcopters, little robots, and generally things that are small enough to make use of their PCBs as a structural component. But an entire CNC machine, soldered together from a few dozen PCBs certainly takes it to the next level.

There is no doubt that 2mm thick fiber reinforced epoxy can be surprisingly rigid, although the Achilles heel of this method might be the solder joints. However, it looks like all load bearing, mechanical connections of the machine are supported by tightly interlocking “dovetail” finger-joints, which may help protecting all the solder connections from the strain hardening effects of continuous stress and spindle vibrations.

As you might expect, most of the wiring is embedded into the FR4 frame construction, and to squeeze the maximum value out of the PCB material, the motor driver boards interface via card edge connectors with the (currently Arduino based) controller board. In addition to the milling head, which features a brushless DC motor and a tool coupler, the team wants to develop heads for circuit printing, microscopy, pneumatic pick and place, hot air reflow, and 3D printing.

With all those cost-driven design choices, from the one-step manufacturing process of the frame and wiring to the dismissal of screws and nuts from the frame assembly, the “FR4 Machine Shield” could indeed become one of the cheapest CNC machine kits on the market. The team targets an introduction price of $400 during a Kickstarter campaign in June 2016. Can they deliver? [Gerrit] checked Pocket NC out at the Faire and ended up raving about how they run their business.

Enjoy their teaser video below!

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EKG Business Card Warms Our Hearts

Giving out a paper business card is so 1960s. Giving out a PCB business card, well that gets you up to the early 2010s. If you really want to stand out these days, give them a fully-functional EKG in a business card. (Note: works best if you’re leading an open-source electrocardiography project.)

Looking through the schematics (PDF), there’s not much to the card. At the center of everything is an ADuC7061, which is an ARM microprocessor equipped with 24-bit ADCs that also has an internal DAC-driven voltage reference connected to one of the user’s thumbs. This, plus a little buffering circuitry, seems to be enough to translate the tiny voltage potential difference across your two hands into a beautiful signal on the included OLED display. Very nice!

Everything (including the big version of their EKG) is open source and made on an open toolchain. If you’re interested in health and medical sensing, you should head over to the project’s GitHub and check it out. The standalone open EKG is based on a much more complicated circuit, and stands to be more accurate. But the business card version is just soooo cute!

Thanks [Ag Primatic] for the tip!

CNC’ed Business Card

Hobby CNC mills have made rapid prototyping easier and faster for hackers. One really useful application is quickly fabricating your own milled PCB’s. [proto logical] built a Reference PCB Business Card using his CNC mill after repeatedly coming across other hackers who were not too convinced about the capabilities of CNC mills in routing PCB’s (also referred to as isolation milling). He thought of making a business card sized reference PCB to show around when he bumps into such folks.

To keep it useful, he included inch and centimetre scales, 0.1″ grid of holes, reference track widths from 16 mil to 66 mil, a few common drill holes and vias and some SMD foot prints. The single sided board is 50 mil thick, so it doesn’t bulk up his wallet. He’s posted the Eagle board file (direct download) and G-code (text file) for those interested in milling their own reference boards. The idea isn’t new – it’s been tried several times in different form factors in the past, generally using more traditional techniques. [proto logical] got inspiration from [Rohit Gupta’s] TinkerRule – The Maker’s Swiss Army Knife. Then there’s the very popular uRuler made by [Dave Jones] of EEVBlog fame. If you have any suggestions on improving the design, chime in with comments here.

Thanks to [ACG] for sending in this tip that he dug up while looking for CNC routed PCB’s.