When everything used wires, it was easy to splice them or replace them. Not so much with PC boards, but everyone has their favorite method for repairing a broken trace. [Mr. SolderFix] has his five favorite ways, as you can see in the video below.
Of course, before you can repair a trace, you probably have to expose it since most boards have solder mask now. Unless you plan to shut the trace at both ends, exposing the actual trace is probably the first step.
What do you do when a PCB is cracked or even broken in two? [MH987] has a plan: superglue the board back and then bridge the traces with solder, solder paste, or wire. The exact method, of course, depends on the extent of the damage.
We’ve had some success with similar techniques, and, honestly, for single-sided boards, we would be tempted to add a thin backer behind the crack. We’ve also used conductive paint to repair traces, but it’s good to have having as many tricks as possible because you never know what will work best for a particular repair. The post mentions that this is easier to do on a single-sided board, but it is certainly possible to do on a two-layer board.
The example repair is a Walkman which — if you are a youngster — was a portable music player that takes cassette tapes. These haven’t been made since 2010, so it is important to repair what you have.
If you can’t repair your Walkman, you could build an updated version. If your board is seriously damaged, you might get hope from this more extreme repair.
For those who wish to go beyond through-hole construction on perfboard for their circuit boards, a printed circuit board is usually the next step up. Allowing for things like surface-mount components, multi-layer boards, and a wider array of parts, they are much more versatile but do have a slight downside in that they are a little bit harder to make. There are lots of methods for producing them at home or makerspace, though, and although we’ve seen plenty of methods for their production like toner transfer, photoresist, and CNC milling, it’s also possible to make them using laser ablation, although you do need a special laser to get this job done.
The problem with cutting copper is that it reflects infra-red, so a higher-wavelength blue green laser is used instead. And because you want to ablate the copper, but not melt the surrounding areas or cut straight through the board, extremely short, high-power pulses are the way to go. Here, the [Munich Fab Lab] is using 9 kW pulses of around 30 microseconds each. With these specifications the copper is ablated from the surface of the board allowing for fine details in the range of about 20 µm, which is fine enough for just about any circuit board. The design of the laser head itself is worth a look.
Aside from the laser, the rest is standard CNC machine fodder, but with an emphasis on safety that’s appropriate for a tool in a shared workspace, and the whole project is published under an open license and offers an affordable solution for larger-scale PCB production with extremely fine resolution and without the need for any amounts of chemicals for the more common PCB production methods. There is a lot more information available on the project’s webpage and its GitHub page as well.
Of course, there are other methods of producing PCBs by laser if you happen to have a 20 W fiber laser just kicking around.
There’s no better way to introduce yourself than handing over a blinky PCB business card and challenging the recipient to a game of Connect Four. And if [Dennis Kaandorp] turns up early for a meeting, he can keep himself busy playing the ever popular game of Snake on his PCB business card.
Quite wisely, [Dennis] kept his design simple, and avoided the temptation of feature creep. His requirements were to create a minimalist, credit card sized design, with his contact details printed on the silk legend, and some blinky LED’s.
The tallest component on such a design is usually the battery holder, and he could not find one that was low-profile and cheap. Drawing inspiration from The Art of Blinky Business Cards, he used the 0.8 mm thin PCB itself as the battery holder by means of flexible arms.
Connect-Four is a two player game similar to tic-tac-toe, but played on a grid seven columns across and six rows high. This meant using 42 dual-colour LED’s, which would require a large number of GPIO pins on the micro-controller. Using a clever combination of matrix and charlieplexing techniques, he was able to reduce the GPIO count down to 13 pins, while still managing to keep the track layout simple.
It also took him some extra effort to locate dual colour, red / green LED’s with a sufficiently low forward voltage drop that could work off the reduced output resulting from the use of charlieplexing. At the heart of the business card is an ATtiny1616 micro-controller that offers enough GPIO pins for the LED matrix as well as the four push button switches.
His first batch of prototypes have given him a good insight on the pricing and revealed several deficiencies that he can improve upon the next time around. [Dennis] has shared KiCad schematic and PCB layout files for anyone looking to get inspired to design their own PCB business cards.
Continue reading “Blinky Business Card Plays Snake And Connect Four”
Carl Friedrich Gauss was, to put it mildly, a polymath responsible for a large percentage of the things we take for granted in the modern world. As a physicist and mathematician he pioneered several fields of study including within the field of magnetism. But since he died decades before the first car was built, it’s unlikely he could have imagined this creation, a magnetic slot-car race track called the Gauss Speedway by [Jeff McBride], which bears the name of the famous scientist.
The Gauss Speedway takes its inspiration from a recent development in robotics, where many small robots can travel around a large area with the help of circuit traces integrated into their operating area. With the right current applied to these traces, magnetic fields are generated which propel the robots. [Jeff] wanted to build something similar, integrated into a printed circuit board directly, and came up with the slot car idea. The small cars have tiny magnets in them which interact with the traces in the PCB, allowing the cars to move with high precision around the track. He did abandon the traditional slot car controller in favor of a push-button style one directly on the PCB too, which means everything is completely integrated.
While this was more of a demonstration or proof-of-concept, some of the features of this style of robot can be seen in this video, which shows them moving extremely rapidly with high precision, on uneven surfaces, or even up walls. Magnetic robots like these are seeing quite a renaissance, and we’ve even seen some that use magnetism to shape-shift.
The first PCBs we built involved a draftsman laying out large pieces of tape. The finished artwork would be photographically reduced to produce the board. This solved a few problems. It was easier to work on the large pieces and any errors were reduced by the scale amount. Boards from this era have a distinct appearance because the tracks are generally curved. But when computer-aided drafting took over, the early packages couldn’t deal with wavy lines making all sorts of angles. So traces started appearing at very common angles like 45 degrees or 90 degrees only. If you use KiCAD, though, there’s no reason to have rectilinear traces. Now there is a plugin to help make your boards appear like old-fashioned circuit boards.
The video by [mitxela] below talks about how we got here and debunks some common myths about PCB design. The plugin produces rounded corners and teardrop-shaped pads. There’s also a second post on the topic with more details. The effect isn’t just ornamental. There are some reasons graceful traces might be better than sharp angles.
Continue reading “KiCAD Plugin Gives Your PCBs That Handmade Look”
There are many ways to create printed circuit boards, but one of the more traditional ways involves using boards coated with photoresist and exposing the desired artwork on the board, usually with UV light. Then you develop the board like a photograph and etch it in acid. Where the photoresist stays, you’ll wind up with copper traces. Hackers have used lots of methods to get that artwork ranging from pen plotters to laser printers, but commercially a machine called a photoplotter created the artwork using a light and a piece of film. [JGJMatt] sort of rediscovered this idea by realizing that a cheap laser engraver could directly draw on the photoresist.
The laser dot is about 0.2 mm in diameter, so fine resolution boards are possible. If you have a laser cutter or engraver already, you have just about everything you need. If not, the lower-power laser modules are very affordable and you can mount one on a 3D printer. Most people are interested in using these to cut where higher power is a must, but for exposing photosensitive film, you don’t need much power. The 500 mW module used in the project costs about fifty bucks.
