In v1
I released Boolflow — a free digital logic simulator that runs entirely in your
browser. v2
made it a real editor. v3
fixed the first thing people saw: a proper home page, so nobody landed on a
blank canvas wondering what to do.
At the end of that v3 post I wrote that "the educational direction is becoming
clearer." v4 is me actually acting on that sentence.
What changed in Boolflow v4
1. Boolflow has a Learn section now — 17 articles, not a blog
The tool could always simulate a full adder. It could never explain what a full
adder is. If you already knew digital logic, Boolflow was useful. If you were
learning it, you had to keep a textbook open in another tab.
So I wrote the textbook into the site. Seventeen articles, structured as a path
rather than a pile of posts:
- Foundations — Boolean Algebra Basics, Truth Tables Explained, De Morgan's Laws, Binary/Decimal/Hexadecimal Number Systems
- Simplification — Karnaugh Maps for Circuit Simplification
- Combinational circuits — Half Adder and Full Adder, Multiplexers and Demultiplexers, Decoders and Encoders, Digital Comparators, Gray Code and Parity Bits
- Sequential circuits — Flip-Flops vs. Latches, Shift Registers, Binary Counters
- Systems — Designing a Simple ALU, Memory Basics (RAM and ROM), FPGAs and Look-Up Tables, Synchronous Design and Metastability
Each one carries a reading time and a set of related articles, so you can
follow a thread instead of guessing what to read next. The order is not
alphabetical — it is the order the concepts actually build on each other.
2. Every article links straight into the editor
This is the part I care about most, and it is the reason the articles live
inside Boolflow instead of on a separate blog.
Every article ends with a link into the circuit editor. You read what a
multiplexer does, and one click later you are wiring one up and toggling its
select line. No copying a diagram from a PDF, no setting up a desktop tool, no
account.
Reading about logic gates and building logic gates are two different skills,
and the gap between them is where most people quit. Putting the two on the same
site is a small thing technically and, I think, the whole point of the project.
3. The whole section exists in three languages
English, Russian and German — 17 articles each, 51 pages in total. English is
the canonical version with no URL prefix; Russian lives under /ru, German
under /de.
I did not machine-translate and forget about it. Technical terms are the part
that machine translation gets wrong in exactly the way that confuses a learner:
"bandwidth" and "throughput" are the same word in some languages until they
aren't, and a wrong term in a teaching text is worse than an awkward sentence.
4. The articles are pre-rendered, so they can be found
A browser-based tool has an uncomfortable property: there is almost nothing for
a search engine to index. One page, a canvas, and a pile of JavaScript. You can
build the best simulator in the world and stay invisible.
The Learn section changes that, but only if the pages actually exist as HTML.
So v4 also brought server-side pre-rendering, a real sitemap covering all 51
article URLs across the three languages, and proper per-page meta tags.
This is the least visible change in the release and probably the one that
decides whether anyone reads the other three.
What Boolflow can do
For anyone arriving here first:
- Drag and drop logic gates onto a canvas
- Connect them with wires and watch signals propagate in real time
- Toggle inputs and see the whole circuit react instantly
- Save and load your circuits as JSON files
- Read the theory and jump straight into building it
- No installation, no login, no server-side simulation — it all runs in your browser
Built with React, React Flow and Tailwind on the front end, FastAPI on the
back.
Why writing the articles was harder than building them
I expected the writing to be the easy half. It wasn't.
Building a simulator lets you hide behind the interface: if something is
confusing, the user can poke at it until it makes sense. An article has no such
escape. You have to decide what a beginner already knows, and every time I
guessed too high the paragraph fell apart.
Writing about metastability in particular forced me to be honest about how much
of it I could explain simply, and how much I had only ever used. There is no
faster way to find the holes in your own understanding than trying to teach
something to someone who has never seen it.
The other surprise: the articles kept pointing back at the tool. Explaining
Karnaugh maps makes you notice that your editor does not help anyone build one.
The Learn section turned into a to-do list for the simulator.
What I want to improve next
- Worked examples inside articles — not just a link to the editor, but a circuit that opens already built, so you can take it apart instead of starting from an empty canvas
- Exercises with checkable answers — "build a circuit that does X", verified by the simulator itself
- Better coverage of the sequential topics — flip-flops and timing deserve more than one article each
- A clearer path through the 17 — right now related links help, but there is no single "start here and follow this" track
Try Boolflow
The simulator is at boolflow.site and the new Learn
section is at boolflow.site/articles.
Free, no account, nothing to install.
I would genuinely like feedback on this release, and specifically:
- If you are learning digital logic: does the article order make sense, or did you hit something that assumed knowledge you did not have yet?
- If you teach this: what topic is missing that you always have to explain yourself?
- Does the link from article into editor land you somewhere useful, or does it drop you on an empty canvas at the wrong moment?
- For Russian and German readers: are the technical terms right? Translated terminology is where I am least confident.
Anything that made you close the tab is the most useful thing you can tell me.
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