No-Etch: The Proof in the Bluetooth Pudding

In a previous episode of Hackaday, [Rich Olson] came up with a new no-etch circuit board fabrication method. And now, he’s put it to the test: building an nRF52 Bluetooth reference design, complete with video, embedded below.

The quick overview of [Rich]’s method: print out the circuit with a laser printer, bake a silver-containing glue onto the surface, repeat a few times to get thick traces, glue the paper to a substrate, and use low-temperature solder to put parts together. A potential drawback is the non-negligible resistance for the traces, but a lot of the time that doesn’t matter and the nRF52 reference design proves it.

The one problem here may be the trace antenna. [Rich] reports that it sends out a weaker-than-expected signal. Any RF design folks want to speculate wildly about the cause?

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Wooing A Lady Into Persisting with Persistence… of Vision

As the story goes, years ago [Matt Evans] was wooing the beautiful and talented [Jen]. There were many suitors vying for her hand; he would have to set himself apart. The trouble was, how to convince her that persisting in the relationship was the best and only course? What did he have to offer? Of course many of us know the answer; having wooed our own significant others with the same thing. Incredible and unrepentant nerdiness.

So! He toiled late into the night, his eyes burning with love and from the fumes of solder smoke. For her he would put his wizardry to work. At the wave of a hand would write songs of adoration in the air with nothing but light. The runes of power, all typed out in the proper order, would be held by a ATiny. A CR2032 coin cell provided the magic pixies which would march to its commands, delivering their spark to the LEDs in the right order.

He etched the board, wrote the code, and soldered the components. He encased it in his finest box of crystal clear plastic and black static foam, a gift of the samples department of the Maxim corporation.

Presumably the full moon was high in the air when he presented the box. He took it out and waved it with a flair. Poetry floated there in front of her eyes. It read, “Jen is cool!”. A few years later, they were married.

The Evolution of a DIY Circuit Board Plotter

In this three part video series we watch [Dirk Herrendoerfer] go from scraps to a nice 3D printed assembly as he iterates through the design of a pen plotter for making circuit boards.

[dana] mentioned [Dirk]’s work in the comments of this post which describes a different process. Many permanent markers stick to copper well enough to last through the chemical etching process. While hand drawing definitely produces some cool, organic-looking boards, for sharp lines and SMDs it gets a bit harder; to the point where it becomes advisable to just let a robot do it.

Of course, [Dirk] was aware of this fact of life. He just didn’t have a robot on hand. He did have some electronic detritus, fishing line, an Arduino, scrap wood, brass tubes, and determination.  The first version‘s frame consisted of wooden blocks set on their ends with holes drilled to accept brass rods. The carriage was protoboard and hot glue. Slightly larger brass tubing served as bushings and guide. As primitive as it was the plotter performed admirably, albeit slowly.

The second version was a mechanical improvement over the first, but largely the same. The software got a nice improvement. It worked better and had some speed to it.

The latest version has some fancy software upgrades; such as acceleration. The frame has gone from random bits of shop trash to a nicely refined 3D printed assembly. Even the steppers have been changed to the popular 28BYJ-48 series. All the files, software and hardware, are available on GitHub. The three videos are viewable after the break. It’s a great example of what a good hacker can put together for practically no money.

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Etching a PCB In Ten Minutes.

Most circuit boards any maker could need for their projects can be acquired online at modest cost, but what if you need something specific? [Giorgos Lazaridis] of has designed his own etching bath complete with a heater and agitator to sped up the process of creating your own custom circuit boards.

[Lazaridis] started by building a circuit to control — in a display of resourcefulness — a fish tank heater he would later modify. The circuit uses a PIC 16F526 microcontroller and two thermristors to keep the temperature of the etching bath between 38 and 41 degrees Celsius. The fish tank heater was gingerly pried from its glass housing, and its bimetallic strip thermostat removed and replaced with a wire to prevent it shutting off at its default 32 degrees. All of it is mounted on a small portable stand and once heated up, can etch a board in less than 10 minutes.

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Homemade EDM Can Cut Through Difficult Materials Like Magnets With Ease

Many years ago [ScorchWorks] built an electrical-discharge machining tool (EDM) and recently decided to write about it. And there’s a video embedded after the break.

The build is based on the designs described in the book “Build an EDM” by Robert Langolois. An EDM works by creating lots of little electrical discharges between an electrode in the desired shape and a material underneath a dielectric solvent bath. This dissolves the material exactly where the operator would like it dissolved. It is one of the most precise and gentle machining operations possible.

His EDM is built mostly out of found parts. The power supply is a microwave oven transformer rewired with 18 gauge wire to drop the voltage to sixty volts instead of the oven’s original boost to 1.5kV.  The power resistor comes from a dryer element robbed from a unit sitting beside the road. The control board was etched using a hand traced schematic on the copper with a Sharpie.

The linear motion element are two square brass tubes, one sliding inside the other. A stepper motor slowly drives the electrode into the part. Coolant is pumped through the electrode which is held by a little 3D printed part.

The EDM works well, and he has a few example parts showing its ability to perform difficult cuts. Things such as a hole through a razor blade., a small hole through a very small piece of thick steel, and even a hole through a magnet.

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Hack a Bike Electroetching

[Melka] wanted a track bike, but never quite got around to buying a nice one. Then he found an inexpensive abandoned project bike for 10 Euro. He had to do a lot of work to make it serviceable and he detailed it all in a forum post. What caught our eye, though, was his technique for electroetching.

The process is simple, but [Melka] says the procedure caused hydrochloric acid fumes as a byproduct. Your lungs don’t like HCl fumes. Apart from the danger, you probably have everything you need. He used electrical tape to create a stencil on the metal (although he mentioned that Kapton tape might come off better afterward) and a saturated solution of common table salt as the electrolyte.

Power comes from a bench power supply set to about 24V. The positive lead was connected to the metal and the ground to the sponge. From the photos, it looks like the particular piece and solution caused about 600mA to flow. After 10 minutes, the metal etched out to about 0.2 mm. After the etching, [Melka] brazed some brass into the etched area to make an interesting looking logo.

If you have a laser cutter, you can skip the chemicals. We’ve even seen laser etching combine with a 3D printer to produce PCBs. [Melka’s] method is a little messier and probably would not do fine lines readily, but if you need to etch steel and you don’t mind the fumes, it should be simple to try.

Brass Clock Face Etched With PCB Techniques

Over the last few months, [Chris] has been machining a timepiece out of brass and documenting the entire process on his YouTube channel. This week, he completed the clock face. The clock he’s replicating comes from a time before CNC, and according to [Chris], the work of engraving roman numerals on a piece of brass would have been sent out to an engraver. Instead of doing things the traditional way, he’s etching brass with ferric chloride. It’s truly artisan work, and also provides a great tutorial for etching PCBs.

[Chris] is using a photoresist process for engraving his clock dial, and just like making PCBs, this task begins by thoroughly scrubbing and cleaning some brass with acetone. The photoresist is placed on the brass, a transparency sheet printed off, and the entire thing exposed to four blacklights. After that, the unexposed photoresist is dissolved with a sodium carbonate solution, and it’s time for etching.

The clock face was etched in ferric chloride far longer than any PCB would; [Chris] is filling these etchings with shellac wax for a nice contrast between the silvered brass and needs deep, well-defined voids.

You can check out the video below, but that would do [Chris]’ channel a disservice. When we first noticed his work, the comments were actually more positive than not. That’s high praise around here.

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