LogiSketch

The story

In digital logic, one equation like A’B’CD’ + A’B’CD + A’BC’D + A’BCD’ + A’BCD + ABC’D + ABCD turns into three separate chores: writing out a truth table, simplifying the expression, and drawing the circuit by hand. If you change one term, you redo all three. I wanted a tool that kept them in sync, so I built LogiSketch.

You type an equation, and everything updates as you type. Underneath is a recursive descent parser I wrote. It turns the text into a structure that drives both the truth table and the circuit, so the two can never disagree. For simplification, I implemented the Quine-McCluskey algorithm. It finds the minimal Sum-of-Products form for you, so you don't have to hunt for it on a K-map.

The part I'm proudest of is the circuit itself. I didn't want it to look like a flowchart, so I drew inputs as SPDT switches and added battery symbols. Power and ground run along shared trunk lines, the way real schematics do. One click rebuilds the entire circuit using only NAND gates or only NO R gates. That "universal logic" idea is easy to state and tedious to draw by hand.

The canvas is fully interactive (built on React Flow) and works on phones. It also exports a PNG report with the equation, truth table, and diagram, ready to drop into a lab write-up.

I built it solo in Next.js and TypeScript between January and February 2026.