Reader Question: How Do You Use Modules and Modular Design?

November 02, 2019 by Kate Smith

Are modules a convenient timesaver? Or a harbinger of changes to how modern engineers design?

The term module comes up a lot around these parts. We want to know how you, the engineers, use modules and think about them in your day-to-day (if you do at all). 

Let's start with a foundational but surprisingly complicated question:


What Is a Module? An Attempt at a Definition

In electrical engineering (and perhaps in other disciplines, as well), the term "module" can be frustratingly vague. Perhaps this is inherent to the term because putting one's finger on a solid definition can be difficult when the word can be used in reference to so many concepts at such drastically different levels of design.

For example, a module for a circuit designer may look either like a component or a daughterboard. For another designer, a module may, in fact, be a large PCB. 


The MT16KTF_64AZ Micron memory module

The Micron MT16KTF_64AZ DDR3L SDRAM unbuffered dual in-line memory module (UDIMM). Image used courtesy of Micron via Digi-Key


u-blox BMD-3 Bluetooth module

The u-blox BMD-3 Bluetooth module. Image used courtesy of u-blox


Here at AAC, Director of Engineering Robert Keim offers the following: "[A module is] a highly integrated electronic component or circuit board that allows an engineer to achieve complex analog or mixed-signal functionality by means of a simplified communication interface instead of custom circuit design." 

Essentially, where a module is employed, the act of creating circuits is entrusted to a third party that then provides a pre-made hardware solution to the EE to integrate into a larger design.


The Trend of Modular Design

Modules are becoming more popular. Part of this equation is the use of modules by the maker community. While there is overlap between EEs and makers, many self-identified makers don't have the formal training needed to design custom circuits. This makes modules a convenient way for them to utilize various components with ease that would have been impossible in decades past. 

Electrical engineering is a different story, but modules are also becoming more prevalent in this space, as well. From RF modules to sensor modules to display modules, there are plenty of products from familiar industry companies that embrace modular design as a core consideration.

A notable example came in February, when muRata, Cypress, and NXP joined forces to provide modules that worked for EEs "out of the box" for "mix and match" IoT applications. The companies' joint public statements highlighted the ability of such a platform to use simplicity and scalability to help engineers streamline the design process.


Abstraction Away from Design or Outsourced Expertise?

From a purely logistical standpoint, the use of modules by EEs may equate to less time spent on granular design. Plug-and-play or drop-in solutions can represent a faster time-to-market, a pain point for a large number of modern engineers.

On the other hand, modules cannot offer the exact same benefits as custom design. Where a skilled circuit designer could develop a custom solution that suits all specs of their application, a module may only generally satisfy them. In this way, modules may result in unneeded functionalities, excess power costs, larger-than-needed footprints, etc.

Since engineering is all about tradeoffs, this may become a matter of deciding which portion of the design process is the most crucial for a given project—fast design or strict adherence to specifications.

Sometimes, modules are inarguably attractive. After all, given how many engineers refer to RF design as "black magic, an RF module may be a welcome addition to the average EE's tool chest. The alternative could be either outsourcing an RF circuit's design to an expert or making the attempt, oneself.


A series of example RF modules

Three examples Image used courtesy of Smithderek2000 [CC BY-SA 3.0]


From a business perspective, it may make sense to remove some of the circuit design complexity from the product development process. This could free up time for EEs to either scale up the number of projects they can work on or perhaps allow them to take on higher-level tasks.

Depending on who you ask, this may be an exciting evolution in the responsibilities of the average EE or a lamentable move away from the artistry of circuit design in favor of respecting tight deadlines and budgets.


Over to You

We want to hear from you. How do you define the term "module"? How have your experiences with designing custom circuits compared to designing with modules? 

Or, if you like:

What is your relationship with modules?

Do you welcome them as a means of more easily and more quickly designing high-performance circuits, or are they displacing skills and activities that are—or at least used to be—essential and rewarding aspects of an electrical engineer's work?

Please share your thoughts with the community on the matter in the comments below.

  • kiwironnie November 07, 2019

    We use modules as described here for prototyping, often before incorporating a device on a custom PCB. Also in a few cases where a module actually works out cheaper to deploy, particularly where it is produced in much larger quantities than our application product (e.g. some RF modules).  For smaller production purposes though, it is still essential that a module and the rest of the sub systems are physically robust and easy to mount, without lots of connecting wires that can be costly to assemble and a source of failures.  Surface mount capability helps with this. We sometimes design our own surface mount modules when there’s a need to swap-in different functions onto the same base PCB.  Usually the base PCB is assembled in a relatively large production run, which can then be deployed for different applications by swapping in the required module(s), typically interfaces and or sensors. Usually only cost effective for small scale production. PCBs are cheap and quick to have fabricated in China, even for small production runs whereas assembly is relatively expensive and much more of a disaster if an error is made. There would be much less need for modules if we had our own in-house automated assembly capability.  Assembly really needs similar revolutionary cheap technology as 3D printing.

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  • Michael Sanders November 16, 2019

    I am of both worlds.  In my current position, my engineering skills are used at the ‘higher layer’ as referred to in the article, and so when i need a solution, typically it’s a one off, or something with a very limited production run.  In this case, the modular approach is faster, more efficient and probably much cheaper than me relearning something over/over.  At same time, i enjoy designing from scratch, and like anything else, if you dont use it enough, you tend to lose skills. At the end of the day, i think designing from scratch is something every EE needs to learn/go thru, if for nothing else, you come out with a better understanding of how to look at modules, and see where they may or may not fit in your system.

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