In the iconic 1990s TV series The X Files, David Duchovny’s FBI agent-paranormal investigator Fox Mulder has a poster on his office wall. It shows a flying saucer in flight, with the slogan “I Want To Believe”. It perfectly sums up the dilemma the character faces. And while I’m guessing that only a few Hackaday readers have gone down the full lizard-people rabbit hole, wanting to believe is probably something that a lot of us who love sci-fi understand. It would be a fascinating event for science if a real extraterrestrial craft would show up, so of course we want to believe to some extent, even if we’re not seriously expecting it to appear in a Midwestern cornfield and break out the probes any time soon.

By All Means Believe. But Don’t Wreck Your Career

Outside the realm of TV drama and science fiction it’s a sentiment that also applies in more credible situations. Back at the end of the 1980s for example when so-called cold fusion became a global story it seemed as though we might be on the verge of the Holy Grail of clean energy breakthroughs. Sadly we never got our Mr. Fusion to power our DeLorean, and the scientific proof was revealed to be on very weak foundations. The careers of the two researchers involved were irreparably damaged, and the entire field became a byword for junk science. A more recently story in a similar vein is the EM drive, a theoretical reactionless force generator that was promising enough at one point that even NASA performed some research on it. Sadly there were no magic engines forthcoming, so while it was worth reporting on the initial excitement, we’re guessing the story won’t come back.

When evaluating a scientific or technical breakthrough that seems as miraculous as it is unexpected then, of course we all want to believe. We evaluate based on the information we have in front of us though, and we all have a credibility pyramid. There’s nothing wrong with having an interest in fields that are more hope than delivery, indeed almost every technology that powers our world will at some time have to overcome skepticism in its gestation period. Perhaps it’s best to say that it’s okay to have hope, but hope shouldn’t override our scrutiny of the proof. Of course I want a perpetual motion machine, who wouldn’t, but as a fictional engineer once allegedly said, “Ye cannae change the laws of physics”.

An Example Here In 2024

All this introspection has been brought to the fore for me by something very much in the present, the so-called hydrogen economy. It’s difficult to ignore our climate emergency, and among the energy solutions aimed at doing something about it, hydrogen seems very promising.

It’s really easy to make from water by electrolysis, there are several ways to turn it into useful energy, and the idea is that if you can store it for later use you’re on to a winner. We’ve seen hydrogen cars, trucks, aircraft, heavy machinery, trains, and even the gas supplanting methane in the domestic grid, so surely the hydrogen future is well under way, right?

Sadly not, because as many a pilot project has shown, it’s difficult to store or transport, it makes many existing metal fittings brittle, and the environmental benefit is often negated by the hydrogen being generated from higher carbon electrical supplies. We still want to believe, but we can’t claim it’s delivering yet.

Whenever we feature a hydrogen-based story, as for example with this experimental storage tech from Swiss researchers, there is no shortage of comments about all of hydrogen’s shortcomings, and some even accuse us of somehow being the snake-oil salesmen shilling the questionable product. I feel this misses the point, that even though in almost all cases the battery is for now the better option, we cover interesting technology stories regardless of judgements over their eventual success. Hydrogen has enough real science and engineering behind it that its problems might one day be overcome, thus we’d be doing our readers a disservice if we didn’t cover it. There are sometimes newsworthy stories upon which we very much take a credible stand based on opinion, but when it comes to pure tech stories such as a hydrogen vehicle we’re simply reporting on the story because we find it interesting and we think you will too. We don’t know that the breakthrough engineering work won’t occur, but we do know that it hasn’t yet.

So when looking at a piece of technology that’s not delivered on its promise, ask for a moment whether there’s a likely “yet” on the end of the sentence without too much of a suspension of credibility. You might find yourself pleasantly surprised.

On the bench where this is being written, there’s a Mitutoyo vernier caliper. It’s the base model with a proper vernier scale, but it’s beautifully made, and it’s enjoyable to see younger hardware hackers puzzle over how to use it. It cost about thirty British pounds a few years ago, but when it comes to quality metrology instruments that’s really cheap. The sky really is the limit for those in search of ultimate accuracy and precision. We can see then why this Redditor was upset when the $400 Mitutoyo they ordered from Amazon turned out to be nothing of the sort. We can’t even call it a fake, it’s just a very cheap instrument stuffed oddly, into a genuine Mitutoyo box.

Naturally we hope they received a refund, but it does raise the question when buying from large online retailers; how much are we prepared to risk? We buy plenty of stuff from AliExpress in out community, but in that case the slight element of chance which comes with random Chinese manufacture is offset by the low prices. Meanwhile the likes of Amazon have worked hard to establish themselves as trusted brands, but is that misplaced? They are after all simply clearing houses for third party products, and evidently have little care for what’s in the box. The £30 base model caliper mentioned above is an acceptable punt, but at what point should we go to a specialist and pay more for some confidence in the product?

It’s a question worth pondering as we hit the “Buy now” button without thinking. What’s your view? Let us know in the comments. Meanwhile, we can all be caught with our online purchases.

Thanks [JohnU] for the tip.

The software and hardware worlds have overlaps, and it’s worth looking over the fence to see if there’s anything you missed. You might’ve already noticed that we hackers use PCB modules and devboards in the same way that programmers might use libraries and frameworks. You’ll find way more parallels if you think about it.

Building blocks are about belonging to a community, being able to draw from it. Sometimes it’s a community of one, but you might just find that building blocks help you reach other people easily, touching upon common elements between projects that both you and some other hacker might be planning out. With every building block, you make your or someone else’s next project quicker, and maybe you make it possible.

Sometimes, however, building blocks are about being lazy.

Just Throw Pin Headers

Back when I was giving design review on a LVDS driver board for a Sony Vaio display, there was a snag – the display used, doesn’t generate its own backlight voltage, so you have to bring your own backlight driver. Well, I didn’t want to bother designing the backlight driver portion of the circuit.

The way I justified it, adding that circuit to the board didn’t make much sense – the entire board was an experimental circuit, and adding one more experiment onto it would result in extra board revisions and reassemblies. Honestly, though, I just really didn’t want to design the LED driver circuit at the time – it didn’t feel as interesting.

So, I had an easy-to-follow proposal – let’s put all backlight-driver-related signals onto three pin headers, forming a “module” footprint of sorts, and then develop the module separately! The hacker agreed, and in the meantime, used a spare panel’s LED backlight to test the display in the meantime – way more accessible of a solution. The pin headers remained, at the time, bound to be unpopulated for, at least, until the next PCB order.

New revisions of the module came and went, now bearing a HDMI port and a whole new ASIC – easy to design, because, again, the hacker didn’t have to worry about the backlight circuit, and just kept the module footprint from the previous design. Was the backlight driver module PCB designed yet? Well, simply put, no.

A friend of mine, just a month later, was designing a motherboard replacement for a tablet computer, and she asked me for advice on how to power the backlight. I thought for a second, and, I had an easy answer for her – use the module footprint. At that point, I still haven’t designed the module, but I didn’t have to mention that. She rejoiced, put the module footprint onto the board, even designed her own neat symbol for it, and then promptly went on to lay out diffpairs and reverse-engineer pinouts, both significantly more fun activities than designing a backlight driver with zero experience in design of backlight drivers.

Some time later, I started getting insistent messages from the original hacker, about needing a backlight driver. The funny part is that by that point, I have already had designed a backlight driver circuit for my own Vaio motherboard, but I never felt engaged enough to turn it into a module. A different friend of mine was looking for small projects, however. I gave her the task: here’s a footprint for a module, here’s a circuit that goes onto the module, and we need a module. Indeed, she has delivered a module – by that point, a module we could put onto three different PCBs.

Building Blocks

The entire occasion definitely helped cement my reputation as someone who delivers, eventually – with big emphasis on eventually. It also brought four people and three projects together, and it let us order the first revision PCB way sooner than otherwise, all because we set out to eventually add the backlight circuit as a module. Now, this module is a building block in our projects – whenever one of us, or maybe one of you, needs a backlight driver, we know that we have an option handy.

I have some unique experiences with PCB modules as building blocks – at one point, I’ve built an entire phone out of them, and I still build devices heavily based on modules. Whenever I’d have the occasion, I’d throw a TP4056 module footprint onto a board instead of reimplementing the whole circuit from scratch. In 2022, I designed a module with a RP2040 and the FUSB302 USB-PD PHY – it was the building block that led to my USB-C series on Hackaday, and eventually helped me, my friends, and other hackers develop a whole lineup of unique USB-C devices.

Building block use and design is the fun way, and it’s the lazy way, and it’s the friendly way – would you believe me if I told you it’s also the safe way? Say, does your circuit need a custom DC-DC, or can you slap a few pads onto the board to connect a commonplace generic module? If you can afford the increased space, might as well make your board as simple as it goes – if there’s less to test and bringup, you’ll get to your project’s finish line earlier, and have less hurdles to jump over.

The Practical Aspects

There are a few techniques you can use if you want to make a building block – pin headers are the simple obvious one. Castellations is a fun one, and here’s a trick – you don’t have to pay JLCPCB for castellated holes, as long as you are fine getting dirty ones, which are still wonderful for prototyping. If you’re using Aisler, you can get perfect castellated holes, though – good for scaling up a module of yours after you’ve verified the design. Don’t be scared of turning through-holes into castellations – it works, and it’s super easy if your board is thin enough. Oh, and you might just be able to get castellations through V-Cuts!

Got an Eastern or Western module, and it doesn’t quite use pin headers? Get out the calipers, measure its pads, and create a footprint for it – you will thank yourself later. I’ve done just once for a 5 V boost module, stocking up on them and putting them onto a bunch of boards. It’s not like I’d feel comfortable designing 5 V boost regulators at the time, so the module has bought me a couple years of worrying about something else instead. The modules have since vanished from the market, but, today I’ve got a few 5 V boost designs I can easily make modules out of. Now, it looks like I can even upgrade my own old boards that are still in use!

When designing your own boards, try to put all pin headers on a grid, 2.54 mm (0.1in) is a must – only use an integer millimeter grid or pin headers if you have no other options. Such a module isn’t just solderable – it’s breadboardable, which helps a ton when you’re trying to figure out an especially daring circuit technique. Castellated modules can be breadboardable, too, if you make sure to concentrate the core necessary signals on two opposite sides!

Are you designing a new module for your own use? See if there’s a footprint you can copy, or an unspoken standard you can follow. Boards speak about themselves through their looks, and footprints convey a purpose through their layout. Look at the boards above- it’s pretty easy to notice that they are TP4056 style battery chargers, but all of them upgraded in their own way. If you follow an existing footprint when designing your own board, it’s going to look more familiar for a newcomer hacker, channeling the power of skeuomorphism where you might not have expected to find it.

The Looks Make The Module

Board formats are underrated when it comes to accidentally creating building blocks. Sparkfun has example layouts for QWIIC devices – follow it, plop a JST-SH connector on, maybe order your PCB in red for a change, and your sensor PCB will shine in a whole new way in your eyes. Dangerous Prototypes, on the other hand, suggests a set of PCB formats known as Sick of Beige that work with existing enclosures and lasercut templates – that’s the surface-level benefit, the real deal is that these footprints also talk the Dangerous Prototypes language. If your programmer board feels like a generic rectangle, putting it into the frame of BusPirate fame will give it the air of hacker-oriented tooling. With both of these formats, you get mounting holes – mark of a hacker who knows what’s good.

Interconnect standards go hand in hand with making your building blocks’ features recognizable without reading the silkscreen – it’s why I talk so much about QWIIC, and a JST-SH connector is always a welcome addition on my boards. Adding a well-recognized standard connector makes your board recognizable as a potential building block. Now, the board looks interoperable if you just give it a chance, equipped with a familiar socket, and perhaps, you won’t feel as much need for designing a new one – quite likely, building a new device in a single day instead of two weeks’ time.

Sometimes, your board will be split apart into building blocks without your involvement whatsoever. Publishing a design that goes beyond connecting a button to an LED? Try to fill in the blanks – it’s about helping the hacker that follows in your footsteps. Sometimes it’s a highschool kid trying to put together a design, and sometimes it’ll be you again, just a couple years later. So, note down the part number of that switcher inductor in the schematic, and fill in the values of the resistor divider while you’re at it – and if you’re revisiting a board of yours where you haven’t done that, do it, then git commit and git push.

Beyond The Ordinary

There’s building blocks everywhere for those with the eyes to see. A single-board computer is one, I’d argue – a SoM in a DDR footprint is one without a doubt. An engineer once showed me a technique for creating building blocks out of thin air – taking unpopulated leftover large project PCBs, then sawing out the section with the circuit you need. Sometimes, you really only need a single piece of that one Ethernet transceiver circuit, and you need it now – you might have not planned for it, but the Dremel tool forgives all.

Circuit blocks are an often requested feature in KiCad. At the moment, you can copy-paste portions of a schematic between projects – which is more than good enough for many circuits. It’s not as great for switching regulators or MCUs, however, and we can’t help but hope to see new advancements in the field soon. Perhaps, one day, you’ll be able to click a few buttons and turn your favourite USB hub into a circuit block – and from there, who knows, maybe you can fill the void that the NanoHub’s eternal out-of-stock state has left in our hearts!