Our journey on model-based software design continues with the Hierarki model train. In previous post, we explained how we partition the embedded software into multiple hierarchical state machines (HSMs) and looked into the…

This is the object diagram showing the main software components, or objects, of this G-scale model train. For embedded systems, an object-oriented architecture is very useful in encapsulating hardware resources. To a microcontroller,…

In the previous post we looked at the state hierarchy of the Train state machine which automatically drives a model train between two stations. It receives an ARRIVING event from the hall-effect sensor…

In the previous post, we introduced statechart as a method for designing asynchronous systems such as this G-scale model train named Hierarki. To see why statecharts are useful, let’s look at two safety-critical…

Asynchronous software design has always been tricky since it goes against our natural sequential thought process using basic constructs like if-then-else, do-while, wait-for-signal, etc. Different languages have their own attempts to tame this…

Let’s take a ride on this G-scale hobby train named Hierarki shuttling between the Upper Garden and Lower Garden stations. It is battery-powered and controlled by an onboard STM32L4S5 discovery board. Apart from…

This G-scale 3D-printed hobby train is equipped with two 320×240 LCD modules, one on each side of the powered unit. They display itinerary information as well as a scrolling banner for some self-promotion!…

Have you noticed quite a few terms we use in development projects are related to trains? If things didn’t go well, software might crash, projects might get off track or even derailed. On…

I like model-based software design, and I love model trains. Why not combine them together? I’ve designed and built this functional G-Scale model train for my hobby projects. It is fully modeled with…