The PinBench canvas showing the clap-rhythm example: an Arduino Uno wired across a breadboard to three LEDs, three push buttons, a piezo buzzer and a microphone module.

Design, code and simulate
Arduino circuits.

Place components on a breadboard, wire them up, write a sketch, press Run — and watch the current move through the wires.

Try it in your browser → Get the desktop app

Component values actually matter

There are other Arduino simulators. Most of them treat a circuit as a diagram. This one solves it.

You can see the current

Dots travel every wire in the direction the current actually runs, with speed, size, brightness and a halo all carrying magnitude across five orders of magnitude — 1 µA to 100 mA. A browned-out LED looks different from a lit one in a still frame, not just in motion. Every other Arduino simulator shows you a static diagram.

A real analog solver

Voltage dividers divide, and an under-sized current-limiting resistor over-drives the LED — PinBench flags the over-current instead of silently ignoring it.

Real firmware, not a mock

An ATmega328P emulation at 16 MHz runs the sketch you actually wrote — timers, interrupts, Serial and all — against that solver.

Parts drawn at true size

An Uno is 68.6 × 53.4 mm on the canvas and holes sit on a real 0.1″ pitch, so legs land where they land in life.

An editor and a serial monitor, not just a canvas

Write the sketch beside the circuit, run it, and read what it prints.

The code editor showing the blink sketch, with the serial monitor below printing repeated Hello World lines from the running simulation.
The blink sketch running — Serial.println output arriving live in the monitor.

Circuit canvas

Drag parts onto a breadboard, wire them with multi-point orthogonal routing, rotate, flip and edit properties. Parts snap to the hole lattice.

Code editor

Arduino-style editing with syntax highlighting, autocomplete and multiple tabs, plus an integrated terminal on desktop.

Serial monitor and plotter

Read Serial.println() as text, or graph the values as they stream.

Undo, redo, autosave

Copy and paste, full keyboard control of the canvas, and work that saves itself as you go.

Plain-text circuits

Circuits are .cdl files you can read, diff and commit. Nothing is locked inside a vendor's database.

Everywhere you work

macOS, Windows, Linux and the web — with multiple windows on the desktop builds.

Components today:
Arduino Uno half & full breadboards LED resistor capacitor potentiometer push button piezo buzzer KY-037 microphone SG90 servo

Describe it, and let it wire it up

The assistant turns a plain-English request into a real circuit and the sketch to drive it — then you check its work on the canvas.

It runs on your machine, not ours

Point it at Ollama, LM Studio or llama.cpp and nothing leaves your computer — no account, no credits, no per-prompt cost, and it works with the network off. Prefer a hosted model? Use your own key with any OpenAI-compatible endpoint. Either way there is no meter running, because we are not in the middle of it.

Circuit and code together

It writes the .cdl and the .ino as one answer, lays the parts out, and you apply it — so the wiring and the firmware agree instead of being two separate guesses.

Then check it by running it

An assistant can be wrong about wiring, and this one says so. The difference here is that you can press Run and find out — against real AVR emulation and a real analog solver, not a diagram.

Start from a working circuit

Each one opens wired up and ready to run — no setup, no sign-in.

What the browser version does

The web build is a genuine preview, not a video. It is also not the whole app — here is exactly where the line falls.

In the browserDesktop only
Open an example and design the circuit Open a local folder and save to disk
Read and edit the sketch Compile your own sketches offline
Run the real simulation Embedded terminal
Serial monitor and plotter Work that persists across reloads

The browser cannot run arduino-cli, so the bundled examples ship precompiled and edited sketches compile through a small hosted service. The desktop app compiles locally and works with no connection at all.

Open source, and buildable

Apache-2.0. Paying is how the project gets funded, not how you get access — there is no licence check and nothing is withheld from the build you make yourself.

View the source Download a signed build

Open it and wire something up

It loads in a browser tab. Nothing to install, nothing to sign up for.

Open the playground →