Design circuits. Simulate instantly.
Write Arduino code, wire up components, and simulate digital logic and analog circuits — all in your browser. No downloads, no hardware, no setup. Just build.
Everything you need to build circuits
From resistor voltage dividers to complex Arduino projects, Scratchboard gives you the tools to go from idea to simulation in minutes.
Arduino in Your Browser
Write, compile, and run Arduino sketches without hardware. Full AVR emulator with GPIO, PWM, timers, and interrupts — all running client-side.
Digital, Analog & Arduino
Simulate digital logic gates, analog DC circuits, and full Arduino projects — all in one editor. From flip-flops to voltage dividers, it just works.
Live Display Emulation
LCD1602, LCD2004, OLED SSD1306, and 7-segment displays render in real time. See exactly what your hardware would show — pixel for pixel.
75+ Components
Logic gates, flip-flops, counters, sensors, servos, motors, joysticks, and more. Build custom components and reuse them across projects.
Built-In Code Editor
Advanced code editor with C++ syntax highlighting, file tree, and tabbed editing. Write Arduino code right next to your circuit.
Analog Circuit Analysis
Analog DC circuits solved in real time. See node voltages, branch currents, and power dissipation — resistors, LEDs, voltage dividers, and more.
From zero to simulation in 3 steps
01
Pick your circuit type
Arduino project, digital logic, analog circuit, or a reusable custom component — each optimized for its domain.
02
Build & write code
Drag components onto the canvas, wire them up, and write Arduino sketches in the built-in code editor.
03
Hit run
Your circuit simulates instantly. Watch LCD displays update, signals propagate, and serial output stream to the console.
Your electronics lab, in the browser
Write Arduino sketches, build analog circuits, and see results instantly. Scratchboard emulates a real microcontroller and solves analog circuits in real time — all in your browser.
- Full microcontroller emulation with timers & EEPROM
- Analog DC analysis — node voltages, currents, and power
- I2C devices — LCD, OLED, sensors wired like real hardware
- Serial monitor output in a built-in console
Frequently asked questions
What is Scratchboard?
Scratchboard is an online circuit simulator that lets you design circuits, write Arduino code, and simulate digital logic and analog circuits entirely in your browser. No downloads or hardware required.
Can I simulate Arduino code online?
Yes. Scratchboard runs your Arduino sketches directly in the browser with support for GPIO, PWM, timers, interrupts, I2C devices, and serial output — no hardware needed.
Is Scratchboard free?
Yes. Scratchboard offers a free plan with up to 3 circuits and 30 minutes of simulation per month. Paid plans start at $7/month for more circuits, simulation time, and premium features.
What types of circuits can I simulate?
Scratchboard supports digital logic circuits like gates, flip-flops, and counters; Arduino projects with full microcontroller emulation; and analog DC circuits including resistors, LEDs, and voltage dividers.
Do I need to install anything?
No. Scratchboard runs 100% in your browser. There is nothing to download or install — just open the website and start building circuits.
What components are available?
Scratchboard includes 75+ electronic components: logic gates, flip-flops, counters, sensors, servos, motors, joysticks, LCD and OLED displays, 7-segment displays, and more. You can also build custom reusable components.
How does the analog circuit analysis work?
Scratchboard solves analog DC circuits in real time. You can see node voltages, branch currents, and power dissipation across resistors, LEDs, voltage dividers, and more.
Ready to build your first circuit?
Join thousands of designers. Free forever for personal projects — no credit card required.