You could even link me a video or site that explains it dumbed down, but I cannot for the life of me understand how something like [this](https://youtu.be/zJxyTgLjIB8) (2:28) works, I don’t understand how those components can shape so many things we use.
In: 3
I’d recommend watching videos on Minecraft redstone circuits. It’s not a 1:1 but it should provide a basis for understanding how logic gates work etc.
Overly simplistic but here goes:
A PCB (printed circuit board) is a board with specific connections and specific components and can be used in many devices for different purposes. The majority of the components regulate voltage and current and different combinations provide different results but the components that are “special” are IC chips (Integrated Circuit ). There are a couple of reasons they are special, but the few that are commonly known is that one, they also have circuits but tiny, and can also be constructed in a way that lets them be programmed. So when you think of something digital, just know that there are a bunch of programmed ICs in them. Every year they get smaller and smaller.
You don’t have to worry so much about what you don’t know, only be satisfied by your curiosity that many don’t possess.
Most of these “maker” style projects are simply assembling integrated-circuit building-blocks that are already created and have programming toolchains. Like building your own PC out of parts, but you’ve got to do the wiring also. Specifying a PCB for manufacture is just connecting data and address communication lines between components. People that have no idea how a field-effect or bipolar junction transistor works or how to make a microprocessor out of them, how a twisted nematic liquid crystal element polarizes light to make a display. While they might program an Arduino to make a Christmas ornament, how to make the equivalent analog application circuit to simply take input, add two numbers, and blink some lights would be lost. 1000 layers of technology is abstracted away by those that came before.
There is simply too much chemistry, physics, engineering, technology for one person to understand and be an expert in everything computer-y; even specialization in one subject, like setting up a PCB production line that can plate buried and blind vias within a multi-layered circuit board from customer Gerber files, is a lifetime of learning and thousands of man-hours.
A circuit board is just a road network for electricity. It has paths that electricity flows from one component to the next. These paths could be carrying power or data so parts can “talk” to each other.
Every part then does something. Some calculate things, some store information, some connect to external sources like SD cards, and so on and so forth.
Let’s go about this from simple to complex. If you want to connect something simple, like an LED to a battery you may solder 2 wires and call it good. Try and do this for something with a lot of pins and it gets real messy fast.
So a PCB is like sticking the wires to a piece of board to hold them still, only done in reverse. You start out with a sheet of copper and remove everything but what will work as a wire in your design.
A circuit board it’s a flat substitute for dozens of wires like spaghetti all over. Each wire is a metal line in the PCB. The material of the PCB acts as an insulator between each line, and the design prevents the circuits to touch one another. The components are your every day use in electrical connectors, (capacitors, fuses, regulators, switches, chips, etc..)
It’s an extraordinary way to simplify an otherwise block of wires, connectors, etc.. and a lot more economic
A PCB doesn’t do all that much, it just makes connections. Its the road network of a city, without it nothing can move in/out but its just there to support not to do
For electricity to move you need to complete the circuit, this means you need to connect various pins on the little components. You can do this [by just soldering wires between the correct pins in point-to-point wiring](https://bgmb55.files.wordpress.com/2012/08/point_to_point.jpg) but as things scale up you’ll stare to go crazy with how many wires are involved. Microcontrollers come with 20-100 pins which each need to be connected, microprocessors can be over 1000, its just not practical to hand place a wire for each of these
So instead we have a board to help us out. A PCB is a core of fiberglass with copper on the outside. Fancier ones will have multiple layers of copper and fiberglass with little copper tunnels(vias) to connect specific wires together. Software is used to design where you do/don’t want copper and then its removed either with a tiny mill for one-off boards or in an acid bath for mass production. Now you have a rigid piece of fiberglass that has your hundreds of little wire connections.
Once you have your board, we do exactly what he does around 2:50 and apply solder paste to it, put all the little components down, then heat the board so the solder melts and joins the metal legs of the components to the tiny copper wires on the board.
PCBs let us make much more complicated devices in much smaller sizes because you can’t effectively solder to a capacitor that’s 0.4mm x 0.2mm but we have machines that can work with those parts. This lets us put a lot of tiny parts into something like a phone which really wouldn’t be possible without a PCB
Pcbs are easy to understand , it’s the components that are hard to understand and how they interact. Generally the pcb just connects components.
Your confusion happens, because you don’t know where the magic is hidden. You assume, that the magic is somewhere on the PCB, while it is almost entirely inside that one ESP32 chip.
The PCB board itself is quite uninteresting. It just a bunch of wires, but they “painted” on a piece of plastic. In this case it mostly just connects things to the ESP32 chip.
* Two switches are used as buttons. They connect wires if pressed, disconnect when not pressed. They are connected to ESP32 chip, so it can check the buttons.
* SD card holder just connects the SD card to ESP32 chip. Several resistors act as “electric springs”: they pull electric levels into “rest positions”, when the SD card is removed, so they do not float randomly.
* The MOSFET is an electric switch, that turns on/off power for LCD screen. Its control wire is connected to ESP32.
* The LCD screen shows images. Its control wires are connected directly to ESP32.
* Two capacitors is “emergency snack stash”. They hold a little bit of electricity in case some components get too hungry. The smaller one is placed directly near ESP32 chip.
* Finally, 6 holes on the side, labeled `3`, `G`, `E`, `B`, `R`, and `T` is used to talk to ESP32 chip and tell it what to do. The `3` and `G` provide power, `E` restarts the chip, `B` tells the chip to disregard previous commands and listen for new, `R` for sending data to the chip, and `T` for listening answers.
So, what is this magical ESP32 thing? It’s actually **an entire computer on a single chip!** Inside, it has:
* 2 CPUs
* Flash memory for permanent srorage
* RAM for temporary memory
* Wifi and Bluetooth radio transmitters
* Ticking electric clock and time counters
* Amplifiers and latches to sense and control electric signals on the pins
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