How I Draw Diagrams for Embedded Development

A short, practical guide for embedded engineers who want instant clarity.

If you’re anything like me, starting an embedded project often feels like dumping a box of LEGO onto the floor.

All the pieces are there… but the picture in your head is blurry.

So before I write a single line of code, before I open VSCode, before I start wiring anything together, I always do one thing:

I draw a diagram.

Not UML.

Not SysML.

Not corporate-architect-powerpoint diagrams.

Just simple boxes and arrows that reflect how the system actually behaves.

And after almost a decade in embedded, I realized I have a very repeatable way of doing this. A workflow that helps me clarify architecture, prevent design mistakes, debug faster, and avoid rewriting code later.

This guide is the exact process I use.

Who This Guide Is For

If you’re an embedded engineer who:

• Gets overwhelmed when starting new projects
• Struggles to keep architecture clear in your head
• Keeps rewriting code because something “felt off”
• Wants a quick, tool-agnostic way to sketch ideas
• Needs better clarity when debugging
• Wants diagrams that translate directly into modules/classes
• Prefers practicality over academic notation

Then you’ll get immediate value from this guide.

Who This Guide Is NOT For

If you’re looking for:

• Formal UML or SysML
• A full architecture textbook
• Enterprise documentation standards
• Code-first workflows with no diagrams
• Hardware schematics or RTOS timing charts
• Tool tutorials (Figma, Draw.io, Mermaid, etc.)

Then this guide will disappoint you.

What’s Inside?

This is not a 300-page architecture treatise.

It’s a 37-page, to-the-point walkthrough of the method I use:

• How I brain-dump components before thinking
• How I group and lay out blocks so the system “snaps into place”
• How I use arrows as interactions (not decoration)
• How I check if a diagram actually makes sense
• How I spot nonsense designs early (LED matrix on ESP32, high-speed ADC on ATmega, etc.)
• How I annotate without clutter
• How I handle incomplete requirements with dotted boxes
• How each box becomes a real module/class
• How to know when a diagram is “done enough”

This is the same workflow I use for hardware blocks, firmware architecture, debugging sessions, real client projects. Basically everything.

Why I Made This

I wrote this because I kept meeting engineers who build incredible things…

but get stuck because their mental model is fuzzy.

When your mental model is fuzzy, your architecture becomes fuzzy.

When your architecture is fuzzy, the code becomes fuzzy.

And when the code is fuzzy, everything slows down.

A good diagram is the fastest way to un-fuzz anything.

This guide gives you a simple workflow you can apply today, even if all you have is a napkin and a pen.

What You’ll Be Able to Do After Reading

• Start new projects with a clear mental model
• Catch impossible designs before coding
• See the system the same way your future codebase will look
• Debug with diagrams that expose inconsistencies instantly
• Build naturally modular architecture (box → class)
• Iterate faster because the system is visible, not abstract
• Draw diagrams that help you think instead of slowing you down

If you want clearer thinking, clearer diagrams, and clearer embedded projects…

Then this guide will help you immediately.

Get the guide and draw your first diagram today.