Free online circuit simulator: Arduino, ESP32, logic gates and breadboard

Simulate Arduino, ESP32-C3/C6, Pico W and STM32 free in your browser: 300+ parts, GPS, RFID, TFT, SD, Wi-Fi, GSM and radio modules, scope and PCB.

28 guided digital-logic builds · Arduino, ESP32 and Pico project guides · Graded exercises

Frequently asked questions

Is there a free online circuit simulator with a breadboard?

Yes: the BitForBytes Embedded Lab runs in your browser for free. Drag parts onto a real breadboard, wire them, and press Run; it simulates the electronics (voltages, currents, LEDs burning out) and the code on the board. No install or sign-up.

Can I simulate an Arduino without hardware?

Yes. Write Arduino C++ for an Uno, Mega or Nano, and the lab compiles it and runs it on an emulated ATmega chip, with serial monitor, plotter, logic analyzer, breakpoints and a variables view. ESP32, ESP32-C3 and Raspberry Pi Pico run MicroPython.

Can I build and test logic gate circuits online?

Yes. The digital-logic parts (switches, probes, gates with 2 to 8 inputs, multiplexers, decoders, flip-flops, latches, counters, registers, RAM, ROM and an ALU) show every pin's level live, and 28 guided builds check your circuit against its whole truth table automatically.

Does it draw a schematic from my breadboard circuit?

Yes. Switch to the Schematic view and the lab draws the circuit with standard symbols, pin numbers and ground and supply flags; while it runs, each net shows its voltage. You can download the schematic as SVG, and export a parts list and a netlist.

What components does the Embedded Lab have?

Over 300: Arduino, ESP32 and Pico boards; resistors, capacitors, diodes, LEDs, transistors, MOSFETs, op-amps and 555 timers; 74HC and CD4000 logic chips; sensors (DHT22, ultrasonic, BMP280, DS18B20 and more); displays; motors, servos, steppers and relays; batteries and power supplies; and bench instruments like an oscilloscope and a multimeter.

Can I simulate GPS, RFID, SD card, TFT, ESP-01, SIM800L or Ethernet modules online?

Yes. Each is modelled as its real chip and works with the usual Arduino library: a NEO-6M GPS sending real NMEA (TinyGPS++), an RC522 reader with MIFARE Classic and NTAG cards to tap (MFRC522), a FAT16 microSD card whose files you can download (SD), ILI9341 and Nokia 5110 displays (Adafruit), a DFPlayer Mini you can hear, an ESP-01 with the AT firmware, a SIM800L that texts and calls a phone in the lab, and a W5500 with DHCP, DNS and real web requests (Ethernet).

Is the BitForBytes Embedded Lab good for engineering students?

It is built for ECE students: it follows a free digital system design course, simulates real part behaviour (including parts failing when misused), grades exercises automatically, and lets a teacher run a class.