Hello y’all! I’ve always been interested in computers and programming for as long as i can remember, but recently i’ve decided to try to get into some of the deeper stuff behind that, into the wonderful world of electronics. Where should I start? What courses or books or youtube series should I consume? What are some high-quality forums, communities, blogs, etc. to learn from?
The most important thing is to tackle projects frequently and get yourself involved with other people doing the same. Learn by doing! I found books, videos, and so on of limited utility by comparison. I'll include an unreasonable quantity of my notes below.
Some useful resources:
Learning Python -- a decent programming language to start with since it's flexible and enforces some good habits : https://python.swaroopch.com/
I'll point out that Microchip Studio is awful and buggy but for some microcontrollers you're stuck with it. Everyone working with embedded systems gets stuck with some lousy manufacturer-supplied software sometimes.
List of initial things to learn:
How to read component datasheets (you will be doing this a lot). Actually I think a lot of my electronics knowledge was picked up from just absorbing datasheets like a weird sponge of some sort.
How to order from Mouser / Digikey / RS Components / Arrow / McMaster (these are also a great source of datasheets)
Basic laws of electricity and magnetism (any freshman university physics textbook is OK -- these pop up used all the time, and even an old one is OK). Just do all the problems in each chapter and you'll be fine. Or you can tackle "The Art of Electronics" if you like.
Soldering is actually pretty easy, just buy some resistors and some prototyping board and get some practice in. You'll need to learn surface mount soldering to get access to good and cheap parts later on, but thankfully, it is way easier than it looks. Like, really a lot easier than people make it look.
How to order manufactured circuit boards from a factory using a design in KiCAD (this is actually pretty easy and cheap!)
These days, a lot of components can be purchased on pre-built 'modules' that fufill a certain objective. For example, a temperator sensing module might have a sensor and all the supporting components on a little board, so you just connect power+ground and data. These are made specifically with learning in mind and are made in Asia at a very reasonable price -- do note though that reading the actual datasheet of the parts in question will give you much deeper knowledge over time.
Tools to buy:
A soldering station. Some people suggest fancy expensive stuff, but frankly, some brands of Chinese tools have gotten quite good. Yihua is a good and affordable brand of soldering station. You can get a soldering-iron-only version if you need to save money, but I'd recommend a model that also includes a hot air rework tool. This makes fixing mistakes on boards way easier, lets you salvage components more easily from junk and failed projects, and also adds a lot of flexibility later on.
A multimeter / parts tester. Should measure voltage, current, capacitance, resistance and diodes. Pro's Kit is an OK brand from Asia.
Eventually you will need an oscilloscope, but not at the start. Hantek, Rigol, and Unit-T make good entry level ones. Siglent is midrange. Tektronix is for rich kids. An old used scope is fine but often shipping is expensive if it's one of the heavy ones.
Tweezers, wire cutters and strippers. Lots of protoboard and solder.
If you're really into low-level microcontroller stuff, an AVR-ICE will be pretty cool to have a few years down the line :)
Platforms and Communities to Consider:
Arduino -- largest friendliest community with the most tutorials, but as such has a ton of beginners and students looking to copy/paste code without understanding. So sometimes it's hard to find someone knowledgeable, and if you do, they might be sort of exhausted. It's probably the best place to start these days overall.
AVR Freaks -- the opposite of Arduino. Hostile, but super knowledgeable. I've learned so much by searching their forums, I've never needed to ask a question! They are great too, but really not a place for beginners to ask questions. It is a good forum to read if you want to learn assembly / C for microcontrollers, but has a steep learning curve -- I'd save it for later :D
Raspberry Pi -- makes everything super easy, generally at the cost of being horribly inefficient and somewhat expensive. It can be a good place to start, but be careful not to learn bad habits here -- e.g. using a whole computer system with Linux to blink an LED. You'll end up having to unlearn a lot to make reasonable battery-powered devices later on. Awesome where processing power is actually needed -- machine vision, some robotics, and AI. The raspberry Pi Pico has fewer of these problems (and you can code in Python!) -- it's pretty fantastic and I would personally choose it as my first microcontroller.
Other Stuff:
Avoid playing with mains power / high voltage until you know what you are doing.
Avoid selling things until you know what FCC / CE is. You can teach courses on what you've learned to fund your studies though! I bootstrapped this way.
Lithium batteries can be sort of tricky / hazardous. When starting out with them, use the metal cylindrical cells at first. The TP4056 is an OK charge controller to use, and pre-built modules are like a dollar in bulk.
I own a prototyping company in Asia, this introduces some bias on my tool recommendations: low cost, high value -- but only 'good enough' performance and convenience. I also hate solderless breadboards and consider them more trouble than they are worth -- some people disagree with me and they are also correct. I also find surface-mount soldering way easier and more reliable than through-hole (most people disagree with me but it's worth thinking about). Finally, I'm a 700 year old Taoist immortal that still uses a slide rule and writes poetry in Assembly language. So I'm part of an older engineering tradition and it's worth keeping that in mind when weighing my advice.
Oh wow! this is a lot of great detail! is Rust at all useful for embedded applications, or am i essentially restricted to C/C++? Is Adafruit also a good resource or not as much as the others? Also, besides the obvious differences in form factor and ease of use, what’s the objective difference between the RP2040 chip, and, for example, Sparkfun’s “Pro Micro” or “Thing Plus”, or is the ease-of-use by itself the main selling point?
There are a lot of differences, but I'll try and go over the high level ones. The RP2040 is a chip, and the others are boards -- so I'll compare the chips on them.
The RP2040 chip is really powerful overall, and does some odd things with I/O that let you do a bunch of very fast, precise things. You also get a lot of I/O pins and they are very well-behaved. The main advantage though is that it works well in both Python and C++, and is well-supported.
The ESP32 based board (Thing Plus) has integrated WiFi. The ESP32 is a great chip, I use it a lot, but it has some unfortunate quirks. First, it has a very high clock speed and decent memory, making it quite powerful. However, if you glitch out the network stack via your code, it can have some problems with unexpected resets. This was much worse with the earlier-generation ESP8266. Secondly, the I/O work much more slowly than the system clock (if I recall correctly), and they are picky about what state they have on startup -- some go high as part of the boot process, others must be high or low on boot but can be used after. This is actually quite a pain sometimes. It's a great chip overall though and works well in C++.
The Pro Micro uses an ATMEGA32 chip. I'm a huge AVR fan so I don't have many bad things to say, I like it a lot. It is much slower than the other two chips though, and has less memory. Probably it's best to use C++, but you ought to be able to use Assembly too if you like. The I/O on AVRs are really well-behaved and usually operate at the same speed as the chip, which is nice when you need precise timing! The best thing about it though, is it can use much less power than the other two options, if you use the sleep modes right. So you can build neat battery-powered applications. Finally AVRs have excellent datasheets -- there's rarely any ambiguity on exactly how any system on the chip works.
Overall, I'd choose an RP2040 board if I wanted to use Python and do IoT/Robots/whatever (you can buy boards with or without WiFi), an ESP32 based board if I wanted to do IoT stuff in C++, and the Pro Micro if I wanted to do low-level, low power embedded stuff in C++ or assembly (and maybe branch out into other AVR chips). The C++ options mean you can use the Arduino IDE and their libraries.
I guess my question to you would be what are your goals? Do you have a project in mind? Do you have a technology, Analog, RF, MCU, FPGA, embedded design? I tend to learn a new thing better when I have an end goal or project to work towards. Depending on where your starting from, a pi might be a good place to start too. You still have most of the I/O and busses of an Arduino, but you can program everything in python, and you have the resources of a full OS too.
Probably stuff like microcontrollers/embedded applications! (I’d like to think) I already know much of the higher-level concepts of computers and how they work, I’ve messed around with programming in Rust or C#, I’ve been daily-driving linux for a few years, I’ve wrote software to do basic tasks for me, but my end goal is to apply my experiences to the physical world. I know very little about the basics of electronics, the physics of it, why PCBs are designed the way they are, etc.
I guess I’d like resources for the lowest-of-the-low-level stuff? Like “How electricity in general works”, “Use-cases for resistors”, “Why you sometimes see capacitors in weird places”, etc.
I’m just now realizing how vague my original question was? i’m sorry about that haha.
I don’t have a particular goal in mind though, i just think this stuff is cool, and I’d like to at some point be able to sit down and make something wacky or useful with KiCad/similar.
I'll start off with your questions are a outside of what I know well. In general to do stuff with electronics, you don't need to know the physics behind it, but the equations that pop out. Mainly V=IR, Almost everything goes back to that. Behind the scenes are lots and lots and lots of differential equations. Alpha Pheonix has a few good visualizations for resistance. He has a water based demo to visualize voltage and resistance, and a maze demo showing how electricity "finds" the path of least resistance. ElectroBoom probably won't teach you too much, but can show some interesting things you can do. EEVblog has some good lectures. For specific applications Digikey and Texas Instruments have some basics, and there are many lectures online available.
I think the questions you asked are a little more on the physics side than the electrical side, and the specifics I think of as a dark art that comes with experience. In general most capacitors you see are blocking DC on an AC circuit, coupling capacitors that are smoothing the power circuit, or capacitors to control/tune something specific. Those control values would be given in a datasheet. Resistors are often going to be current limiting, voltage dividing, or "pulling" a high impedance signal. To design something you often just need the rule of thumb, and not necessarily a deep understanding of "why".