fr4

26 Articles

Laser Blasts Out High-Quality PCBs

January 11, 2021 by 53 Comments

With how cheap and how fast custom PCBs have gotten, it almost doesn’t make sense to roll your own anymore, especially when you factor in the messy etching steps and the less than stellar results. That’s not the only way to create a PCB, of course, and if you happen to have access to a 20-Watt fiber laser, you can get some fantastic homemade PCBs that are hard to tell from commercial boards.

Lucikly, [Saulius Lukse] of Kurokesu fame has just such a laser on hand, and with a well-tuned toolchain and a few compromises, he’s able to turn out 0.1-mm pitch PCBs in 30 minutes. The compromises include single-sided boards and no through-holes, but that should still allow for a lot of different useful designs. The process starts with Gerbers going through FlatCAM and then getting imported into EZCAD for the laser. There’s a fair bit of manual tweaking before the laser starts burning away the copper between the traces, which took about 20 passes for 0.035-mm foil on FR4. We have to admit that watching the cutting proceed in the video below is pretty cool.

Once the traces are cut, UV-curable solder resist is applied to the whole board. After curing, the board goes back to the laser for another pass to expose the pads. A final few passes with the laser turned up to 11 cuts the finished board free. We wonder why the laser isn’t used to drill holes; we understand that vias would be hard to connect to the other side, but it seems like through-hole components could be supported. Maybe that’s where [Saulius] is headed with this eventually, since there are traces that terminate in what appears to be via pads.

Whatever the goal, these boards are really slick. We usually see lasers used to remove resist prior to traditional etching, so this is a nice change.

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An Easier Way To Roll Your Own LED Ball

July 14, 2020 by 1 Comment

Yes, circuit sculptures are amazing. But the patience and skill required puts most of the designs we’ve seen fairly far out of reach of the average beginner. We totally understand — not everyone finds fun in fiddly, structural soldering.

[Hari Wiguna] was captivated by the LED ball that [Jiří Praus] made last Christmas and figured there had to be less painful ways to cover a sphere in blinkenlights than printing a negative to use as a soldering jig. Turns out there is at least one way — just design the structure to use PCBs in place of brass rod, and fit everything together like a 3D puzzle made of FR4.

This SMD LED ball is almost ready for prime time. [Hari] wants this to be accessible for everyone and completely parametric, so he’s still working out the kinks. Check out the current form after the break as [Hari] rolls the ball through the various display modes using an Arduino and talks about the failures along the way, like having to file out the LED slots because they were designed too tightly the first time. [Hari] is also working on the friction fit of the pieces so the ball is easier to assemble, especially at the beginning.

3D prints as circuit sculpture soldering jigs are great tools, don’t get us wrong. How else are you gonna solder brass rod together on a curve?

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Drill Thrice, Solder Once

December 27, 2019 by 28 Comments

If you design printed circuit boards, then you will have also redesigned printed circuit boards. Nobody gets it right the first time, every time. Sometimes you can solder a scrap of 30gauge wire, flip a component 180°, or make a TO-92 transistor do that little pirouette thing where the legs go every-which-way. If you angered the PCB deities, you may have to access a component pad far from an edge. [Nathan Seidle], the founder of Sparkfun, finds himself in this situation, but all hope is not lost.

Our first thought is to desolder everything, then take a hot iron and tiny wires to each pad. Of course, this opens up a lot of potential for damage to the chip, cold joints, and radio interference. Accessing the pin in vivo has risks, but they are calculated. The idea is to locate the pin, then systematically drill from the backside and expose the copper. [Nate] also discovers that alcohol will make the PCB transparent so you can peer at the underside to confirm you have found your mark.

In a real, “fight fire with fire” idea, you can rework with flex PCBs or push your PCB Fu to the next level and use PCBs as your enclosure.

High-Speed PCB Design Hack Chat With Bil Herd

September 23, 2019 by No comments

Join us on Wednesday, September 25 at noon Pacific for the High-Speed PCB Design Hack Chat with Bil Herd!

Printed circuits have become so commoditized that we seldom think much about design details. EDA software makes it easy to forget about the subtleties and nuances that make themselves painfully obvious once your design comes back from the fab and doesn’t work quite the way you thought it would.

PCB design only gets more difficult the faster your circuit needs to go, and that’s where a depth of practical design experience can come in handy. Bil Herd, the legendary design engineer who worked on the Commodore C128 and Plus4/264 computers and many designs since then, knows a thing or two in this space, and he’s going to stop by the Hack Chat to talk about it. This is your chance to pick the brain of someone with a wealth of real-world experience in high-speed PCB design. Come along to find out what kind of design mistakes are waiting to make your day miserable, and which ones can be safely ignored. Spoiler alert: square corners probably don’t matter.

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, September 25 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. Continue reading “High-Speed PCB Design Hack Chat With Bil Herd” →

Fail Of The Week: How Not To Light Pipe

August 19, 2019 by 17 Comments

You’d think that something made out of glass and epoxy would transmit a decent amount of light. Unfortunately for [Jeremy Ruhland], it turns out that FR4 is not great light pipe material, at least in one dimension.

The backstory on this has to do with #badgelife, where it has become popular to reverse mount SMD LEDs on areas of PCBs that are devoid of masking, allowing the light to shine through with a warm, diffuse glow – we’ve even featured a through-PCB word clock that uses a similar technique to wonderful effect. [Jeremy]’s idea was to use 0603 SMD LEDs mounted inside non-plated through-holes to illuminate the interior of the board edgewise. It seems like a great idea, almost like the diffusers used to illuminate flat displays from the edge.

Sadly, the light from [Jeremy]’s LEDs just didn’t make it very far into the FR4 before being absorbed – about 15 mm max. That makes for an underwhelming appearance, but all is certainly not lost. Valuable lessons about PCB design were had, like exactly how to get a fab to understand what you’re trying to do with non-plated holes and why you want to fence the entire edge of the board in vias. But best of all, [Jeremy] explored what’s possible with Oreo construction, and came away with ideas for other uses of the method. That counts as a win in our book.

LEDs Shine Through PCB On This Tiny Word Clock

March 27, 2019 by 22 Comments

Everyone seems to love word clocks. Maybe it’s the mystery of a blank surface lighting up to piece together the time in fuzzy format, or maybe it hearkens back to those “find-a-word” puzzles that idled away many an hour. Whatever it is, we see a lot of word clock builds, but there’s something especially about this diminutive PCB word clock that we find irresistible.

Like all fun projects, [sjm4306] found himself going through quite the design process with this one. The basic idea – using a PCB as the mask for the character array – is pretty clever. We’ve always found the laser-cut masks to be wanting, particularly in the characters with so-called counters, those enclosed spaces such as those in a capital A or Q that would be removed by a laser cutter. The character mask PCB [sjm4306] designed uses both the copper and a black solder mask to form the letters, which when lit by the array of SMD LEDs behind it glow a pleasing blue-green color against a dark background. Try as he might, though, the light from adjacent cells bled through, so he printed a stand that incorporates baffles for each LED. The clock looks great and even has some value-added modes, such as a falling characters display a la The Matrix, a Pong-like mode, and something that looks a bit like Tetris. Check out the video below for more details.

We’ve seen word clocks run afoul of the counter problem before, some that solved it by resorting to a stencil font, others that didn’t. We’re impressed by this solution, though, enough so that we hope [sjm4306] makes the PCB files available so we can build one.

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CNC Turns A Single PCB Into Origami Hemisphere

January 13, 2019 by 8 Comments

Trying to make a hemispherical surface out of a PCB is no easy feat. Trying to do that and make the result a working circuit is even harder. Doing it with one solid piece of FR4 seems impossible, right?

Not so much. [brainsmoke] came up with a clever way to make foldable, working PCBs that can be formed into hemispheres. The inspiration for this came from a larger project that resulted in a 32-cm diameter LED-studded sphere, which a friend thought would make a swell necklace if it was scaled down. That larger sphere was made somewhat like a PCB soccer ball, with individual panels soldered together. [brainsmoke] didn’t relish juggling dozens of tiny PCBs to make a necklace-sized version, so the unfolded pattern for half a deltoidal hexecontahedron was laid out as one piece on single-sided FR4. The etched boards were then cut out on a CNC mill, with the joints between the panels cut as V-grooves from the rear of the board. By leaving just enough material to act as a live hinge, [brainsmoke] was able to fold the pattern up into a hemisphere while leaving the traces intact. The process was fussy and resulted in a lot of broken FR4 and traces, but with practice and the use of thicker board material and heavier copper, the hemisphere came together. The video below shows the final product

This objet d’art is [brainsmoke]’s entry in the Circuit Sculpture Contest, which is just wrapping up wrapped up last week. We can’t wait to share some of the cool things people came up with in this contest, which really seemed to get the creative juices flowing.

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