I’ve been getting really curious with IOT… I want to try using a Siemens PLC on par with Arduino or my own PCB's.

So, we first need to cover what a PLC (Programmable Logic Controller) is… A PLC has a MCU inside but it was developed for a more hostile environment (industrial). PLC tend to be extremely expensive (around 10K USD Dollars) and the needed software to program them is not free nor opensource like its counterpart (Arduino Boards). Do to this normally to see interact with one you would have needed to work in a place that could afford this hardware and software. SIEMENS changed the game by developing a small PLC that is in a more accessible cost range and named it LOGO!.

LOGO! 8 Structure (Download User Manual to See this Picture)

EcoStudio has a really small Fab Lab Inventory. This makes it hard to interact with different MCU’s to compare their similar or different characteristics.

My classmates and I can only work with the ATtiny 45. I wanted to test more MCU’s because I have basic experience with the ATmega328P (Arduino UNO R3) and ATmega2560 (Arduino Mega R3). Due to EcoStudio's slow response to arraigning Arduino Kits for Fab Academy students to take home during the pandemic, I was forced to ask my brother to send me one of my Arduino from home (Honduras to Panama). My brother sent me my Arduino Mega just in case I needed extra horsepower. I have Arduino kits too but they were to expensive to sent from Honduras to Panama. I finally received a small kit from EcoStudio (April/16/2020) to start working with some of the components.

I started by reading more about the ATtiny 45. During week 6 (Electronics Design) I spent a lot of time reading my MCU’s data sheet, because I was trying to design the RESET circuit to integrate on my PCB to. MCU’s can look identical from the outside, but they can be a different world internally. Finding the name of the MCU the first step so that you can immediately scavenger its appropriate data sheet (different venders have different parameters for their final product). The next important step is to find the pinout of the MCU and make sure that you’re counting the pins in the appropriate order (a small circle marks pin #1 and count up – down not right - left ).

Depending on the MCU’s family you can have some similar or different characteristics. They make look the same but they can have important differences like: operating temperature, maximum operating voltage, frequency range, etc... The serial communication capabilities are really important to know too. Depending of the type of serial communication some characteristics change (positively or negatively). The user needs to know the nature of it project and determine the pest type of communication that suit the requirements.

The best OS for many reasons is Linux. The problem is that people get scared when they see it without playing around with it first.

I don’t want to virtualize Linux in my laptop, so I’ll be using my Raspberry Pi 4. This Raspberry has a big advantage compared to the older versions, because you can buy one with a maximum of 8GB of RAM. The Raspberry Pi 4 has different variants with 2GB, 4GB or 8GB of RAM. The performance of the Pi is going to depend on: RAM, SD card specs, Linux distribution and thermal dissipation. I’ll be using the 8GB Pi, Samsung EVO SD card, a case with passive thermal dissipation (most cases with active thermal dissipation eliminate easy access to the GPIO pins) and I’ll use a project called desktopify. Through the desktopify project I was able to use an optimized version of Ubuntu MATE 64bits. I recommend watching ETA PRIME’s videos regarding the subjects. I found a video in ETA PRIME YouTube channel explaining desktopify and also gives a perfect tutorial on how to install it. The only step I would add is to use the official SD Card Association Formatter first if you are using an SD card (new or old).