Raspberry Pi 5 Goes Under The X-ray

December 10, 2023 by Jenny List 1 Comment

Most Hackaday readers will know to some extent what lies inside their computer, even if this is only at a block diagram level listing the peripherals. But what is physically on a modern computer board? [Jeff Geerling] has subjected a Raspberry Pi 5 to a medical imager, and shares with us the many layers of parts and PCB he found there. With a six-layer board and a heap of large BGA chips on it, there’s a lot to look at.

For readers who are used to working with printed circuit boards, it’s likely the techniques involved in the design will not be new. For us, the magic lies in the scale. The sheer number of interconnects on the board is impressive enough, but when it becomes possible to peer into the SoC package it becomes evident that there’s an internal PCB with some of the smallest vias we have ever seen. [Jeff] goes on to show us part by part around the board, on the way reminding us that some of the earliest Pi boards had to be reworked to replace Ethernet jacks without magnetics.

There’s a beauty to these ghostly images which might not be apparent to anyone who hasn’t stared obsessively at a PCB in a CAD package while it takes shape. The images show the work of the PCB designer’s art at a fine scale. We’d almost go as far as to suggest they be viewed as fine art instead of industrial design. Take a look, the video is below the break.

If this art is a bit big for you, then look at ASIC design – which takes things down to the microscopic level of the doped silicon structures within these amazing chips.

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Designing A PCB GPS Antenna From Scratch

October 18, 2023 by Donald Papp 15 Comments

These days, when it comes to GPS devices the antenna is typically part of the package. But what better opportunity for [Pepijn] to learn how to make a GPS antenna from scratch for a badge add-on?

A patch antenna is an antenna of a flat design, which [Pepijn] was going to put directly on a PCB. However, there was added complexity due to GPS being a circularly polarized signal, and that meant doing some research.

Sadly, nowhere did [Pepijn] encounter a straightforward reference design or examples, but in the end success came from going with a truncated corner patch antenna design and using simulation software to figure out exactly what dimensions were needed. (The openEMS free simulation software didn’t bring success, but the non-free Sonnet with a trial license did the trick.) The resulting PCB may not look particularly complex, but every detail matters in such designs.

KiCad handled the PCB CAD design but the prototype came from cutting the PCB on a CNC machine instead of having it fabricated and shipped; a much cheaper and faster option for those with access to the right tools. A bit more testing had the prototype looking good, but the real proof came when it successfully received GPS signals and spewed valid NMEA messages. The design files are on GitHub but as [Pepijn] says, the project was about the journey more than anything else.

PCB Repair Is A Sticky Proposition

October 14, 2023 by Al Williams 9 Comments

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.

An In-Depth Comparison Of Hobby PCB Manufacturers

October 13, 2023 by Richard Baguley 46 Comments

[Icamtuf] has been working on a prototyping run of a project, which involves getting PCBs made by several low volume PCB manufacturing companies. After receiving the boards, he analyzed the results and produced an interesting analysis.

The project he is working on is Sir-Box-A-Lot, a Sokoban gaming console clone that we’ve covered before. It uses an AVR128DA28 microcontroller to emulate the original box-pushing game and drive the OLED display. He ordered PCBs from OSHPark, DigiKey Red, JLCPCB, PCBWay and Aisler.

OSHPark boards are gorgeous, but you pay for it.

There were pros and cons for each of the services: OSHPark produced the nicest-looking boards, but at the highest cost. DigiKey Red had a flawless solder mask, but a rather sloppy-looking silkscreen and shipped the boards covered in adhesive gunk. JLCPCB was fast, shipping the boards in less than 7 days, but the smaller details of the silkscreen were blurry and the solder mask was thinner than the others. The solder mask from PCBWay was very slightly misaligned but was thicker than most, and they were the only ones who queried a badly shaped hole to see what [Icamtuf] wanted to do: the others just made assumptions and made the boards without checking.

To be fair, this analysis is based on a single PCB design ordered once and it is possible that some companies were having a bad day. These were also delivered to the US, so your delivery times may vary. So, there are no clear winners and I wouldn’t make a choice based on this alone. But the analysis is well worth a read if you want to know what to look out for on your own PCBs.

Screech Owl Is A Tribute To The Eowave Persephone

October 12, 2023 by Lewin Day 6 Comments

The Eowave Persephone was a beautiful thing—a monophonic ribbon synth capable of producing clean, smoothly varying tones. [Ben Glover] used to own a nice example that formerly belonged to Peter Christopherson, but lost it in the shifting sands of time. His solution was to build one of his own from scratch.

It’s a simple build, but the final result puts out a nice pleasant sound.

Known as the Screech Owl, the build is based around a custom shield designed to suit the Arduino Leonardo. The primary control interface is a Softpot 500 mm membrane potentiometer, layered up with a further thin film pressure sensor which provides aftertouch control. The Leonardo reads these sensors and synthesizes the appropriate frequencies in turn.

All the electronics is wrapped up inside a tidy laser-cut enclosure that roughly approximates the design of the original Eowave device. [Ben] noted the value of services like Fiverr and ChatGPT for helping him with the design, while he also enjoyed getting his first shield design professionally manufactured via JLCPCB.

It’s a tidy build, and in [Ben’s] capable hands, it sounds pretty good, too. We’ve seen some other great ribbon controlled synths before, too. Video after the break.

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How Small Can The ESP32 Get?

September 7, 2023 by Bryan Cockfield 25 Comments

At its core, the ESP32 chip is not much more than an integrated circuit, a huge mass of transistors sealed inside an epoxy resin package with some leads. Of course, most of us won’t buy discrete ESP32 chips with no support circuitry since it’s typically easier and often not that much more expensive to get them paired with development boards of some type for easy access to things like USB and GPIO. But these tiny chips need little in the way of support to get up and running as [Paul] demonstrates with this tiny ESP32 board.

The project started as a challenge for [Paul] to build the smallest ESP32 that would still function. That means carving away nearly everything normally found accompanying one of these chips. There is no charging circuitry, only one of the GPIO pins is accessible, and it even foregoes the WiFi antennas which eliminates the major reason most people would reach for this chip in the first place. But at this form factor even without wireless capabilities it still blows other chips of this stature, like the ATtiny series, out of the water.

Even though [Paul] built it as a challenge, it goes a long way to demonstrate what’s really needed to get one of these chips up and running properly. And plenty of projects don’t need a ton of I/O or Wi-Fi either, so presuming these individual chips can be found cheaply and boards produced for various projects its an excellent way to minimize size and perhaps even power requirements. You can make these boards even smaller than a USB-A connector if you want to take this process even further, too.

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Thin Keyboard Fits In Steam Deck Case

September 6, 2023 by Bryan Cockfield 13 Comments

Although some of the first Android-powered smartphones had them and Blackberries were famous for them, physical keyboards on portable electronics like that quickly became a thing of the past. Presumably the cost to manufacture is too high and the margins too low regardless of consumer demand. Whatever the reason, if you want a small keyboard for your portable devices you’ll likely need to make one yourself like [Kārlis] did for the Steam Deck.

Unlike a more familiar mechanical keyboard build which prioritizes the feel and sound of the keyboard experience, this one sacrifices nearly every other design consideration in order to be thin enough to fit in the Steam Deck case. The PCB is designed to be flexible using copper tape cut to size with a vinyl cutter with all the traces running to a Raspberry Pi Pico which hosts the firmware and plugs into the Steam Deck’s USB port. The files for the PCB are available in KiCad and can be exported as SVG files for cutting.

In the end, [Kārlis] has a functioning keyboard that’s even a little more robust than was initially expected and which does fit alongside the Deck in its case. On the other hand, [Kārlis] describes the typing experience as “awful” due to its extreme thinness, but either way we applaud the amount of effort that went in to building a keyboard with this form factor. The Steam Deck itself is a platform which lends itself to all kinds of modifications as well, from the control sticks to the operating systems, and Valve will even show you how.