The auto keyword was introduced with C++11. It reduces the amount of code you have to write, reduces repetitive code and the number of required changes. Sadly, many C++ developers are not aware of how useful this keyword is. Especially embedded code can gain a lot by its usage. In this article, I try to…
Units of Measurements for Safe C++ Variables
In your program code, you often deal with unitless values. You can add the units of measurements in the variable or function name, or by adding a comment, but there is still the risk you accidentally make wrong conversions. I will describe how to handle units of measurements for common time values using a custom…
Real Time Counter and Integer Overflow
After writing the article about event-based firmware, I realised there are some misunderstandings how real-time counter are working and should be used. Especially there is a misconception about an imagined problem if such counter overflows. In this article, I try to explain this topic in more detail, using example code for the Arduino IDE. What…
Class or Module for Singletons?
Should you use a class or a module with a namespace for a singleton interface in your firmware? I found there are many misunderstandings which lead beginners to make a wrong decision in this matter. With this article, I try to visualize these misunderstandings with simple example code for the Arduino platform. Before we start,…
Event-Based Firmware (Part 2/2)
In the first part of this series, we explored the general concept of event-based firmware. To read that article, follow this link. The concepts we discussed were directly tailored to one specific firmware. Now, let’s develop those concepts further to build an event system that can be integrated into many different applications. First, we’ll look…
Event-based Firmware (Part 1/2)
You start with small, simple firmware. But with each added feature, the complexity grows and grows. Soon, you need a good design in order to maintain the firmware and ensure the code remains clean and readable. In this article, I explain the event-based approach for writing firmware. I use the term “event-based” because it is…
A New Modular CMake Based Toolchain for Feather M0 HAL
In the past months, I developed firmware for a few Adafruit Feather M0 based projects. The reason why I use the Adafruit Feather platform, instead of using an MCU directly, is for modularity. By using a board on sockets, it can be replaced at any later time with a more powerful one – or by…
My Personal Programming Language Recommendation Shift over Time
I am developing software for 20+ years now. In the early days, I developed software in Assembler, Basic, Fortran, Pascal and C. Meanwhile my focus gradually shifted over time. It is a very personal view, with my own language recommendations I gave over time. Languages I never recommend are missing in this article, even I…
Inline AES 256 / CBC Implementation
Today I like to share some encryption code, which can be used in various situations – and is also useful for embedded systems. It is a unique implementation of the AES 256 / CBC crypto algorithm. The goal of this implementation was neither speed nor size. It was written to inline it into existing code….
Tiny Particle Sensor Node with Decorative Case
This article is about a small sensor node with a decorative case. It is based on the Raspberry Pi Zero W board with a custom sensor shield on top. I publish all hardware files for a simple version of the sensor, so you should be able to build this kind of sensor nodes and use…