Abundant opportunity

I’m spoilt.

It’s not that I was born with a silver spoon in my mouth, I wasn’t.

Nor is it that I live in California as it’s not unequivocally the Golden State anymore.

It’s simply that we live in an age of abundant digital maker products.

The most recognizable in this niche world might be the runaway British success that is the Raspberry Pi.

All good history buffs know the Romans made remarkable things long before north Europe was “civilized” and so it is with the Italian Arduino boards that brought us the word “Blinky”.

What makes this a Golden Age is the accessibility to not just boards but boards at price points that in some cases are as cheap as a cup of coffee but also the abundance of supporting material that allow a broader audience to successfully own, use and adapt this potpourri of gems.

Core memory from 1970s era IBM 370

While Brits and Italians might be unlikely movers in this digital revolution, the landscape is very global with not just a strong leadership from the US but a remarkable Chinese component.

My entire adult life has been spent in and around tech. The first whopper of a computer I used as a student had little donuts wired together by amazingly adapted humans that was its central run time memory.

We’ve come a long way from the nostalgia piece above.

An oasis of abundant opportunity for me and all the way down to kids in every school and almost every home.

Now that’s a Golden Age!

Station automation, an unlikely interest area ….for me

My first exposure to the need and value of station automation came during a trip to Prince Edward Island, Maritime Canada in 2018. Renting K6LA’s station was a journey into an Aladdin’s cave of radios and gear. I was fascinated.

Gear galore at K6LA’s PEI station in 2018

In my quest to touch as many bases, I broadly wanted to build a “learning bench” for ham radio station automation. With so many options and avenues, I decided to use the Feather family of boards from New York’s unusual success, Adafruit. These standardized and not surprisingly small boards have a fixed form factor and standardized pin out configuration while offering a huge mix of CPUs and interface/connectivity options. Exactly what I need for my station automation learning bench that presumably needs various communication methods, expand-ability and various ways (switches, screens etc) to interface and communicate intent.

Documentation and examples wins the day

The battle Royale between Motorola and Intel in the 1970/1980s was won hands down by Intel and not through having a better design (they didn’t) but through having an amazing support system for designers and manufactures with detailed documentation, examples etc etc.

This is what makes Adafruit so attractive to me and in consequence I’m happy to pay a premium versus an eBay or Amazon el cheapo clone/knock off/look alike.

Whether it’s a Jeep borne or plane borne radio station, small, light and rugged are keywords for gear and many commercial systems fail the small and light metric. Wires galore is another aspect of ham radio and this is somewhat a hassle when assembling a portable/transportable radio station

My “learning bench” therefore is aimed at using digital maker technology to reduce, streamline, make more redundant/resilient some of what I’m dragging around in the hold of a plane or the roof of my Jeep.

Twiddling gear with 12v

Any radio that finds itself in close proximity with others quickly finds a medley of filters, switches etc being brought into play to protect one radio from another. Radio receivers are stunningly sensitive devices often multiplying a weak signal a million fold to extract a voice and conversely a radio transmitter, typically feet away from the receiver is pumping out huge amounts of energy that could reek havoc in a receiver.

The “standardized” method to instruct automated filters, switches etc that make up the safe separation of receive and transmit signals is by twiddling voltage to either zero or twelve on pins tied to certain functions such as engage a 10m filter, or engage a 40m filter or route radio waves from this input to one of many outputs.

An example of a black control box asserting 12v on different lines select antenna stacking features

With this in mind one half of my learning work bench would be a platform to assert twelve volts on different connectors attached to an automated filter, automated switch etc.

Having built one before and wanting to do better and staying within the spirit of learning more, I decided to design a simple board using KiCad, freely available software and have my design manufactured by a service in the US. Once I have my board/PCB, it’s my job to populate it with whatever my design dictated in the way of chips, transistors, resistors etc.

Splitting things.

Part of my premise is that too many wires and cables exist that connect station gear together and as more gear is added, neat and tidy becomes a rat’s nest. In a “permanent” station this can be hidden and typically once done, isn’t reconfigured often. In the Jeep or DXPedition world, the station is being constructed and de-constructed every time.

In my photograph above of the Stack Match and associated black control box, the thought is to split the black control box and locate the 12v twiddler functionality next to the Stack Match and “remote” the front panel (used to select antenna combinations) to a “control head” either being a world of buttons or a Node Red accessible.

The connectivity between the 12v twiddler and control head could be one of many including WiFi (my favorite), LoRa or even wired ethernet or CanBus.

To a real board created by OSH Park in the USA

Remote “control” side of my “learning bench

As a kid growing up in London in the 1960s, I vividly remember seeing NASA’s Mercury capsule on display at my ever favorite London Science Museum. Buttons and switches everywhere and with them a lasting love was born to press things.

Decades later the passion is still strong and I design another Feather centric PCB that has 18 buttons and a 3.2” touch screen. My left red, grey, green stack is used to “instruct” my remote 12v twiddled attached to the Stack Match to select one or two antennas with various phasing options.

Control side…

Step one – design and prototype

Google can be your friend and searches throw up everything from ideas lost in ads to ideas so succinctly shared that it’s a joy to borrow, enhance and experiment my way forward.

Modern day “breadboarding” to verify components and software ahead of committing to a PCB

Free to you, free to me

While it’s fashionable for some to deride large US tech companies, truth is they pioneer a lot of advanced software techniques and tools making many available for free. Maybe less altruism than pragmatism and being pushed by the open source movement, either way we the community (both hobbyist and commercial) benefit.

Microsoft’s Visual Studio has long been considered a professional grade development environment and the “community” edition has more features than I’ll probably ever master but its my go to for embedded development were possible.

Microsoft’s free Visual Studio environment

Step two – Learn KiCAD

Day one is always intimidating when tackling something completely new. As I really had no idea what level of sophistication was needed in a PCB design tool, I shied away from Autodesk’s Eagle product as the free looked too feature restricted and I plunged headlong into an oddly successful European piece of free software called KiCAD.

KiCAD screen showing a typical circuit diagram that will be transformed into a manufacturable PCB

YouTube can be your friend sometimes and it’s hard to get radicalized watching software tutorials. A slow and often painful iteration of watch, pause, try cycles day after day eventually got me to a design I thought might actually work. Success is much more than transcribing an electronic circuit design to KiCAD’s visual language as ultimately it’s about manufacturability. Parts and especially similar ones (such as a connector for headphones) come in a mind boggling variety of subtly similar packages. Ensuring my choice has the correct dimensions for pin separation is critical. If my board expects three pins from my headphone connector arranged in a straight line but I order one with them in a triangular layout, I’m screwed.

In the States we are spoilt in having electronic parts stores that literally carry 100,000s of components (at least pre Covid). Parts acquired and time to be patient as I wait on my PCB.

Step three – outsource to PCB manufacturer – OSHPark

Hobbyist PCB manufacturing has transformed from etching copper with toxic chemicals that not only are harmful but hard to dispose of practically to a world of remarkable choice driven by the Internet. With a standardized language to define how to manufacture a PCB, options for boards in my hands in days from China exist through to more prosaic US manufacturing taking weeks. Philosophically believing in supporting local and domestic businesses, I opted for OSHPark. Used and loved by many hobbyists, I submit my design, share credit card details and sit back for what seems an eternity and then 21 days later its just like Christmas.

Step four – Stuff those boards and success!

Successful PCB design is a little binary in that the smallest issue or error can render the project an abject failure. Diligence, checking and rechecking prior to submitting the design to OSHPark paid off and after rather joyfully stuffing and soldering buttons, capacitors, connectors and all manner of mundane garden variety components, first power netted success. Issues did exist but were easily remedied with a little solder and wires.

A better, more contemporary button cluster and LCDNode-Red

I recently made a serious effort to master the fundamentals of Node-Red. Simplistically, it’s an easy way to create applications with visual display/interaction accessible via a web browser. Node-Red could run on my contest logging computer that has limited free real estate and could serve up a web page to control a “distant” WiFi connected 1703. In essence the iPhone is replacing my remote control head with my 18 buttons and little screen.

iPhone mounted in Jeep next to K3s can be a Node Red soft button cluster as shown below
Node-Red “buttons” displayed on an “old” iPhome

What’s next?

This has been a fun start to a journey. Learning is rewarding but it’s even more rewarding when the designed boards pretty much work.

An obvious next step is to experiment using a low pin count M0 ARM CPU chip or even the new RPi 2040. Enormous amounts of reference designs are available to help me along. However, ideas seem to begat too many other ideas and the world of LoRa is interesting in of itself.


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