Free Online Circuit Simulator with Arduino, ESP32 & Raspberry Pi

An Arduino simulator that runs real code

Most online Arduino simulators only pretend to run your sketch. Here, your code is compiled with the official Arduino toolchain and the resulting firmware runs on a simulated ATmega328P chip in your browser — the same instructions that would run on a real Arduino Uno. Libraries such as Servo, LiquidCrystal I2C and Adafruit NeoPixel work as they do on the real board.

The circuit itself is solved electrically, so an LED without a resistor, a button wired to the wrong rail or a short circuit behaves the way it would on your desk.

ESP32, Raspberry Pi Pico and Raspberry Pi in Python

Switch the board to an ESP32 or Raspberry Pi Pico and program it in MicroPython with the familiar machine, neopixel and i2c_lcd modules, or pick a Raspberry Pi and use gpiozero or RPi.GPIO. Breakpoints and single-stepping let students see exactly which line is running.

Beginners can use block coding instead of text; the blocks generate Arduino C++ or MicroPython that you can read and edit.

Parts and instruments

Build on a full-size breadboard with parts found in most starter kits:

• LEDs, RGB LEDs, resistors, push buttons, slide switches, potentiometers and buzzers.
• Servo motors, NeoPixel strips, 16×2 I2C LCD displays and seven-segment displays.
• Light, temperature, ultrasonic distance and motion sensors whose readings you can change during the simulation.
• A serial monitor, multimeter and oscilloscope to measure what the circuit is doing.

Test before you buy, then print the case

Try a project before ordering components, check your wiring before connecting a real board, or teach a whole class without a single kit. When the circuit works, press Case in 3D to open a matching enclosure in the free 3D Designer, and buy the boards and parts from our store in Amman.