A way to facilitate your work, contributions and repairability

Why is modularity useful?

When developing projects in the open, it is really useful to see what is available out there and how it could be incorporated in a project to save time and effort. In other words, if someone for example has already created a good system to measure temperature, there is quite often no point in starting from scratch and develop the same system again. More effective would be to replicate the already existing temperature measuring system and adapt it (where necessary) to the project’s needs.

From Wikipedia:

Modular design, or modularity in design, is a design principle that subdivides a system into smaller parts called modules which can be independently created, modified, replaced, or exchanged with other modules or between different systems.

Modularity is used in open hardware projects because it makes it easier for others to take the parts that are useful to them and create derivatives, or contribute to specific features. Modularity is also really useful when a device breaks down, to easily detect and isolate a malfunction. Think of updates: if your design is modular, one module can become obsolete but you will be able to update it without changing the whole device.


To make this re-use/replicability possible, projects need to be developed with modularity in mind. That means, could this example (temperature sensor) be developed in a way that its documentation and building are done in a modular way?

In documentation this would mean highlighting the exact components in the system that are responsible for temperature sensing, and how it communicates with the rest of the system. In design/building, it would mean that the temperature sensing function is self-contained within a group of specific components, that can be replaced or modified easily.

In this way if another project wants to use just that function, it can easily find out what parts are needed and how it can be implemented somewhere else. Modularity is also useful within the project, as a certain module can be used more than one time in different parts of the system.

In short, once a module has been developed, it can be used by other projects (which increases the chances of that module being improved/supported over time), again in the same project and over time, in different projects by the same developers. Last but not least, this also helps with sorting components, as different projects with the same modules will require similar components.

Examples and use cases

One good example of modularity comes from the world of hobby electronics, where companies sell “breakout boards”. These little boards, normally contain all the components necessary to perform a specific function. For example, you could buy an DC motor/Stepper motor controller, learn how to use it to control the axis on a 3D printer, but later on use the same module to control the motor that drives the wheels in a toy car.

Assignment: Review your project in terms of modularity

The following questions can guide your way towards modular design:

  • Which are the main functions required for your hardware to operate?
  • Based on that, how many would modules you need to create and how would they group the components of your project? E.g., power module, microcontroller, communication, temperature sensor
  • How would you interconnect those modules? How much space will your modules take once interconnected? (Think of enclosures!)


next: A minimal viable project  

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