How to start?​

Most of the electronics needs some brain to be able to make something meaningful. That brain is processor. There are countless processors from simple with AVR architecture to more complex like ARM processors. Processor choice is depending on usage. You have to consider many parameters like price, size of package, number of GPIO pins (general input output pins) energy consumption, memory size, processor frequency and other parameters. One of the most important parameters is how easy is to develop on that platform. The easiest way to start developing is to start with Development kits. I will introduce you the most known ArduinoRaspberry PI, ESP32.

Arduino

arduino
Arduino UNO

It was 2005 when prototyping platform Arduino as educational tool for students based on 8-bit Atmel processors was born. The Arduino community created graphical integrated development environment (IDE) and libraries which significantly simplified work with GPIO ports.

Students can create super easy software that will control PWM (pulse width modulated) based on voltage measured on other pin of processor. As a user, instead of assembling breadboard with processor and all necessary components, you just plug Arduino board to the computer with USB cable, open programming interface and choose one from many examples with most used functions and use-case scenarios. 

Pros:

  • price (you can get one of these from 3 USD), simple development, size, low power

Cons:

  •  limited memory for code (only few kilobytes for software), slow CPU clock

Usage:

  • Sensors processing, controlling LEDs, motors and other actuators, sending data

    Raspberry PI

    raspberry pi 3
    Raspberry PI 3rd generation

    Raspberry PI, just like Arduino was created as project for students supporting informatics on schools. Unlike Arduino, Raspberry PI is complete PC in the size of the bank card. It runs Linux operating system, it has all input and output interfaces necessary for work on this PC like USB, HDMI and ethernet. It has also GPIO to work with. Raspberry PI is however multiple time more powerful than Arduino and it can handle more power demanding applications like AI, computer vision, video transmission etc. 

    Pros:

    • High computing power, price, work just like with PC, very good support on internet, internet connection

    Cons:

    • Higher current consumption, booting time

    Usage:

    • Smart home control, video streaming, control of actuators, robots

      ESP32

      ESP 32 with sensors on the prototyping board

      ESP32 is module based on powerful 32 bit processor with one or two cores with frequency up to 240 MHz. It has bluetooth and wifi interface so its suitable for wireless applications. Arduino community created “arduino core” thanks to you are able to program it in Arduino IDE or use script languages as Javascript, Python, Lua and more. Wifi and bluetooth can work in the same time which is great benefit in IOT applications. You can connect to the module other accessories like OLED display. ESP 32 thanks to low price between 2 and 5 USD, high computing power and good support is becoming more popular on IOT field.

      Pros:  

      • high computing power, price, WIFI+bluetooth, low current consumption

      Cons:

      • Higher power consumption

      Usage:

      • Communication module, IOT, actuators control, displaying sensor data

        Breadboard

        In case you want choose specific processor or you can’t find right development kit and you don’t want create whole PCB for it, you can use prototyping board (breadboard). It’s a board with series of holes which are electrically connected together in lines and divided horizontally into left and right side. You can insert components into board to create prototype without soldering. 

        Designing PCB​

        After you proved the functionality of the prototype  with development kit or breadboard, you can rewrite this connection to EDA (electronic design automation) software like Eagle or KiCad. The process of PCB design starts with block scheme. Block scheme is map of connections between components without knowledge of their actual position on the PCB.

        PCB scheme
        PCB scheme

        After block scheme is created you have to switch to “PCB design” mode. You will draw PCB shape and place all components on the PCB. Then you have connect components with routes. There are two ways how to create routes on PCB. The first is Autoroute which is powerful tool for automatic creating routes. This method however is not the most optimal regarding the PCB properties. Sometimes even autoroute can’t resolve some routes so it’s better do it yourself. This topic is for whole blog so i will cover it in future blog. 

        PCB design
        Completed PCB design

        PCB production​

        After the scheme and PCB design is done we can produce the final PCB.  You can easy create the PCB at home. You can choose from several methods. For simple PCB you can  stand with universal PCB. There are holes on the universal PCB similar to breadboard. Horizontal lines on the board are connected together. Connection between lines are made with cables or tin.   

        universal PCB
        Universal PCB
        universal pcb board backside
        Connection between components on the universal board

        PCB etching​

        Ironing​

        Ironing method is consist of printing routes design with laser printer on transparent foil or paper. 

        PCB design on paper
        Printed design on the paper

        Then you will put the foil or paper on laminated  copper board and iron it. The PCB design will transfer on the copper board.

        PCB ironing
        Cleaned PCB board ready for ironing

        Afterwards sink the board to the solution of FeCl3 which dissolve all copper instead routes. Then rinse the PCB with water and clean all remaining toner from routes by rubbing alcohol and PCB is done. All steps will be in covered  future blog. 

        etched PCB
        PCB after etching
        shiny new PCB
        Finalised PCB

        Pros:

        very cheap and fast prototyping

        Cons:

        Toner is not always transferred very well on the board, so some routes can be broken and need to be joined by tin.
        Not good for thinner routes.