Free Circuit Simulator Online — Wire, Compile, Run
Free Circuit Simulator Online — Wire, Compile, Run
Sensbench is a free browser circuit simulator where you wire real components on a canvas, compile real Arduino/ESP32 firmware, and watch circuits run — no install, no account, no hardware. Breadboard an LED, sweep a servo, filter PWM, or flash a virtual board with firmware compiled by a real arduino-cli backend.
What you get
- Real firmware compilation — Arduino and ESP32 sketches are compiled by a real arduino-cli backend, not interpreted
- Interactive canvas — drag wires, place components, press buttons, turn pots while the simulation runs
- SPICE analog engine — resistors, capacitors, diodes, transistors and op-amps behave like their real curves
- Digital logic gates — AND, XOR, NAND, flip-flops and a full adder run on the digital gate engine
- Serial Monitor built in — every board example prints real serial output you can watch live
Supported targets
| Arduino Uno | arduino:avr:uno |
|---|---|
| Arduino Mega 2560 | arduino:avr:mega |
| Arduino Nano | arduino:avr:nano |
| ESP32 DevKit | esp32:esp32:esp32 |
| Raspberry Pi Pico | rp2040:rp2040:rpipico |
| STM32 Blue Pill | STMicroelectronics:stm32:GenF4 |
Try these examples
Arduino Uno Blink LEDRead the write-up →
Voltage DividerRead the write-up →
Relay-Controlled LEDRead the write-up →
AND Gate AlarmRead the write-up →
Pico Blink LEDRead the write-up →
FAQ
Is the circuit simulator really free?
Yes. Every example opens in the browser with code and wiring pre-loaded — no account, no install, no time limit. The only paid part of the platform is AI Builder project generation and extra MCP compiles, which are separate from the simulator.
Does it compile real Arduino code?
Yes. Sketches run through a real arduino-cli backend for the AVR, ESP32 and RP2040 cores, so pin numbers, libraries and timing match what you will flash to physical hardware. SPICE and logic circuits use their own engines on the same canvas.