How to learn this stuff?

You have the most important skill of all - the right attitude.

I'm not a traditional academic myself when I went to school (back in the days of stone tablets) everyone had a career. The boys went into heavy industry and the girls became secretaries, shop workers wives and mothers. Like many lifelong-learners I have picked up various skills just by doing the work. Woodwork for example can go all the way from sticking a few planks together with a hammer and nails all the way to cabinet making or wood carvings with incredible detail.

Any skill worthy of study requires a lot of practise and the most important thing is to start at the beginning with something really simple. Matt's projects range from fairly simple to moderately complex to ... unique like his recent projector or breathing PC.

OK, so the first thing is to have a look and see what excites you. For me, it was always audio which came from my love of cinema as a child. Back then I couldn't afford the equipment to make films so I gravitated to radio plays which required a simple cassette recorder and a microphone. 

The bug grabbed me and before I was even in my teens I was poking around the insides of very dangerous equipment while lacking the knowledge to keep myself safe. Several fairly nasty electric shocks, and a number of years later, I gravitated to AM radio receivers starting with crystal sets (radios that didn't even require a battery) and rapidly to small (cough) technically illegal (cough) transmitters and even to making small AM receivers by hand miniaturising them so they could fit into a matchbox, powered from a single 1.5V cell.

I made a lot of mistakes because I had no one to help me and the only way to learn stuff was to read magazines but that involved reading and I don't read well. I'm am audio/visual learner. So when we got a colour television I would devour anything that demonstrated new technology.

YouTube has been a massive boon and although I did train in electronics in the early 1980s things I learned back then have changed almost beyond recognition. Components are smaller, more complex and crucially, faster. Much, much faster. 

There was a time when we all thought that 100 MHz was the upper limit for a CPU and we'd never beat it. Home PCs ran around 4 - 8MHz with simple displays, often limited to monochrome or 16 colours. VGA didn't come along until later. Monitors shrunk from huge, heavy blocks to massive flat panels with millions of colours and so on.

Coming back to the hobby, inspired by Matt's beautiful USB-C microphone, it was like starting again. Not that unlike it would be picking someone up from 19th Century England and dropping them in modern day California.

I tell you this tale to illustrate why its so difficult to get into electronics these days. The drive for smaller, faster parts has aided in the development of some amazing projects with their own computers, many times faster than the computers we programmed by hand (literally) to machines a fraction of the size, a fraction of the price and with capabilities (WiFi, Bluetooth, I2S... and so on) BUT that came at a huge cost in terms of making things increasingly difficult for hobbyists to break in.

Soldering, for example, is a key skill that you can only really learn by doing. Trying to design your own stuff comes later. But experimenting with designs much more complicated than a "night light" that turns on in the dark (we called them automatic candles) is now a lot harder because companies are moving rapidly from "through hole" parts to surface mounted parts with connections so small they have to handled with tweezers and soldered under a microscope. (You can doge that one using a hot-air station and some other bits and bobs but they run expensive for even low-quality gear and honestly, cheap stuff is cheap for a reason.)

As things stand we can still buy through-hole parts but they are increasingly rare. When Matt created the USB-C mic he managed to source parts like the THAT1512 and the parts needed to make it work but such devices are becoming rare. Transistors in particular (which we could just nip to the local Tandy, Maplin, brick and mortar store etc.) to get are now getting harder to find. Thankfully there's still eBay and a thriving community of hobbyists, mostly radio amateurs who keep just enough interest to keep a shrinking library of parts in supply. 

Rather incredibly you can still get valves (tubes) but the vast majority are either used or NOS (new old stock) which means they have been found in rusty old stores, often from Russia. 

But valves need very high voltages to work (one of my current experiments uses "low voltage" valves that are driven from a USB supply with a boost converter). They are incredibly dangerous for the untrained or self-taught. You can't just power these things up and stick a probe in to measure voltages because there's a high chance you'll suddenly find yourself talking about the perils of high-tension with St. Peter.

So you're rather limited in what you can do to learn but fortunately there are still ways to build a skill-set using experimenter's breadboards and learn to solder using pre-made solder boards with pre-wired pads. Veroboard (the tradename) also known as stripboard is the usual go-to for this. Indeed that's what Matt used for the mic project and, if you can solder already, it's quite a straightforward job.

If you can't though, stripboard, particularly the nasty stuff from China is a nightmare. The trouble is, while the strips of conductive material - copper - are separated, you have to cut them - a small drill works but many people just use a craft knife - cutting their pinkies in the process. And worse, it's very easy (when you're learning) to apply too little or too much solder to the joint and things won't work.

One chap I particularly admire is Mr Solderfix:

https://www.youtube.com/@mrsolderfix3996

He has videos on all sorts of techniques from basic soldering all the way to repairing busted boards. 

For learning how stuff works, some channels of interest (among many) are Big Clive, Electroboom and as you get more advanced, EEVBlog (Dave Jones). Each of these creators have not just well produced videos with sensible language and often great humour, but they are also excellent resources for learn. Clive (famous for coining the name the Joule Thief), a super little starter project by the way) does teardowns and explains how each part functions. He's especially interested in keeping people safe - and will explain beautifully just how dangerous some of the Chinese imports are: even ones that claim to conform to our higher standards in the West.

Dave Jones has a series called "Fundamental Fridays" where he takes and explains simple building blocks first on the whiteboard and then with a practical example.

Of course these are only a few of the hundreds of channels you can pick from. I won't name and shame anyone but there are quite a number with bad or even dangerous information. If you see someone soldering parts without using a PCB, you can usually guess they are not safe or at least, do stuff that most people shouldn't. That's not to say every channel that does "point to point" is bad, but it's tough to know which ones are and which are not. You might be risking components in some cases, in others you could be risking your life.

Tesla coils are an example. While the smaller ones using circuits like The Slayer (so named because it breaks the very transistors that make it work!) might only give you a tickle, the larger ones (driven from a simple wall wart) could turn you into a smoking hole in the ground. Saves on the cremation at least.

Returning to PCBs, modern boards are covered in a special coating called solder resist - which solder won't stick to. This helps us (not just noobs, but old gits like me) to solder small parts with close pin spacing with relative ease. It was invented for machines (early systems used molten solder that washed over the solderable) side so something was needed to ensure the solder only went on the copper pads.

These days you can buy boards (I've designed some for DIY Perks) that have multiple pads specifically to build small projects. As these boards are produced by JLCPCB (or any other board shop of your choice) they come with the solder resist on both sides making it a lot easier to learn. Small ones are available from Amazon but they are expensive when compared to the 100mm square monsters like "Claire" with its hundreds of holes and now four-layers to give your project a better chance at working first time. The downside of those is you have to order them yourself, minimum five at a time and the economy postage means waiting a couple of weeks for them to arrive.

I won't duplicate the work of people like Mr Solderfix here, he can teach you more in less time.

One thing I'll repeat here (and this is important) is you should always use solder with lead (Pb) and tin (Sn) in a 60/40 setup with internal flux. Tin gives solder that lovely shine but lead, while highly toxic if not handled correctly - it's not edible! - makes the solder flow almost like water when heated to a little under 200 degrees C. The lead free stuff (required under the new environmental regulations) flows like thick custard and has to be heated to around 400 degrees to get it to move well.

Temps like this will burn you (even 200C will take your skin off) but the poor flow characteristic of lead free makes it very difficult to hand solder. Machines are fine as they go through a series of steps to warm the components and board before the solder melts and a cool-down phase to ensure it bonds correctly. Anyone who has worked with a modern board will tell you this stuff is a pain in the bum.

While lead is toxic to all life on Earth, it's not toxic when used correctly. Like cyanide, it's inert until it comes into contact with stomach acid. At that point, it enters the blood stream and over time causes lead poisoning that will eventually rot your brain. Terms like "Potty" and "Mad as a Hatter" derive from the days of early pottery and millinery where lead was used freely as part of the manufacturing process, with many of the old lads going crazy before their 40s and dying horrible deaths. Lead also infects the "germ cells" meaning the damage passes down through generations of children, often to grandchildren leaving them with horrible and life-long disabilities. More recently this was discovered in farming where a material used as an insecticide (lead arsenate, lead and arsenic) was poisoning crops and even getting into the workers themselves. It's use has been banned in most parts of the world now but *still* appears in some tobacco products: another reason why smoking is so dangerous!

Boiling lead does give off toxic fumes and easily enters the bloodstream that way, but the boiling point of lead is far higher than a soldering station can reach so you're OK.

The main point is to wash your hands after handling it - just to be safe - and don't sit munching on a sandwich while you're making a project up. The smoke is just the flux and while it's not really toxic, a fume extractor (a small USB fan is fine) is nicer to have.

TL;DR

So in conclusion, buy yourself a low-cost (but reliable) soldering setup. I like Antex but there are several others, just don't cheap out or you'll be making life more difficult and soldering (well) takes a lot of practise. Applying just the right amount of molten solder to a joint, which, itself has to be heated, takes some time to master. A cheap iron will be too large (a fine tip is essential) too hot or too cold. Temperature controlled irons are not too expensive now and make life somewhat simpler. (I learned using an iron with a tip the size of your thumb - and that's not an exaggeration - which had to be heated using a naked flame!)

Of course, I didn't have to work with tiny components like we have now.

Start out simple. 

Good quality automatic wire strippers are a good buy too. Sure, you can use a knife (don't unless you love the sight of blood or enjoy waiting in hospital) or your teeth (definitely don't do that if you value your teeth). 

You can get kits of parts like resistors, transistors, capacitors and inductors on Amazon or eBay with a selection of common values. These are great for experimenting as they are cheap but beware the cheap breadboards as the contacts are quite flimsy and these 1/8W (typically) resistors are a nightmare as they don't make good contact and/or fall out when you least expect it.

Any questions, feel free to hit me up.