Arduino, running the sketch you wrote
arduino-cli compiles it, an AVR8 core executes it instruction by instruction, and the LCD shows what the ATmega328P actually put on the bus. Uno, Nano, Mega and ATtiny85, no board on your desk.

Hardware is all about iteration. Velxio lets you wire a circuit, program the board and run it in seconds, real firmware on a real solver, right in the browser.
DFRobot · M5Stack links on this page are affiliate links: a purchase through them earns Velxio a small commission at no extra cost to you.
Nothing on this page is a scripted animation: the firmware is compiled and executed, and the circuit around it is solved.
arduino-cli compiles it, an AVR8 core executes it instruction by instruction, and the LCD shows what the ATmega328P actually put on the bus. Uno, Nano, Mega and ATtiny85, no board on your desk.

arduino-cli or ESP-IDF compiles the sketch, then AVR8, RP2040, RISC-V, Xtensa or ARM executes it instruction by instruction. What the OLED draws and what the serial monitor prints is what the chip actually did.

ngspice compiled to WebAssembly runs a full nodal analysis about 60 times a second. GPIO pins drive real nets, ADC inputs read solved node voltages, and probes report RMS, DC and current wherever you drop them.

Adders, comparators, decoders, flip-flops and a 1-bit ALU slice: no microcontroller anywhere, just gates, switches and LEDs solved as a real net. The classroom half of electronics, without the breadboard.

The M5Stack Cardputer with its keyboard, Seeed's round display keeping time, Pimoroni's Badger 2350 driving e-paper, and DFRobot's UNIHIKER M10 in the catalogue alongside them. Their makers sent the hardware so the emulation could be checked against the real thing.




35 boards across 6 CPU architectures — AVR8, ARM Cortex-M, ARM Cortex-A, RISC-V, Xtensa, and Linux. Including partner boards from Pimoroni, M5Stack, Seeed Studio and DFRobot. All running locally, no cloud needed.
One institution contract gives every student in the class a full Pro account. No per-seat checkout, no card details in a classroom.
Private projects, BOM and schematic exports and GitHub Sync, for everyone enrolled.
Billed once to your institution, per semester or per year. Volume pricing on request for large cohorts.
Arduino, ESP32, RP2040, STM32, ATtiny and Raspberry Pi, with SPICE analog solved alongside the firmware. Not a sandboxed mock.
The simulator stays free forever, WiFi with internet included. Paid plans unlock the Linux and STM32 boards, custom WiFi networks and the local network gateway. Maker and Pro add the AI agent; No AI leaves it out.
Discover the simulator + light AI help.
The full workbench, zero AI. You write every line.
For makers shipping real circuits with AI help.
Private projects, GitHub Sync and BOM exports.
Questions, bugs and ideas: the Discord and the issue tracker are open, and so is every line of the simulator.
An interactive Esp32 C6 circuit simulation you can run free in your browser on Velxio, by kshyhoo.
// STACJA POGODOWA - ESP32-C6 (VELXIO)
// Wzorowane na sprawdzonej, dzialajacej wersji z Wokwi:
// - globalny HTTPClient http; (nie tworzony na nowo w kazdym wywolaniu)
// - odczyt strumieniowy zamiast http.getString() (mniej alokacji na stercie)
// - wysylka HTTP na osobnym zadaniu (sendTask)
// - heap_caps_check_integrity_all() do wczesnego wykrywania korupcji sterty
// - WiFi.begin(ssid, pass, wifiChannel) NIE POMINIETE
//
// UWAGA: ESP32-C6 ma JEDEN rdzen - sendTask dzieli rdzen 0 z loop()
// przez preemptywny scheduler. Cale I2C w jednym zadaniu = jeden punkt
// dostepu do magistrali, brak przeplatania transakcji miedzy kontekstami.
//
// Kazdy czujnik probkowany niezaleznie; brak jednego NIE blokuje reszty.
// NAN = "brak wiarygodnej probki" -> w URL poleci "nan" -> floatval() w
// PHP zamieni na 0.0 (bezpieczne dla json_encode).
//
// Podzial rol miedzy czujnikami (bez duplikacji funkcji):
// AS5600 (0x36, I2C) - kat obrotu choragiewki WZGLEDEM OBUDOWY stacji
// BMM150 (0x13, I2C) - azymut magnetyczny SAMEJ STACJI (kalibracja/Polnoc)
// -> suma AS5600 + BMM150 = prawdziwy kierunek wiatru
// BME280 (0x76, I2C) - temperatura, wilgotnosc, cisnienie (JEDYNE zrodlo)
// TSL2561 (0x29, I2C) - naslonecznienie (Lux)
// Water Level (0x77+0x78, I2C, 2x ATtiny1616) - poziom deszczowki w zbiorniku
// GUVA-S12D (analog, pin 4) - indeks UV
// Anemometr (open-collector, pin 5) - predkosc wiatru (impulsy)
// D7S (0x55, I2C) - wibracje/sejsmika: intensity (SI) + PGA
#include <WiFi.h>
#include <Wire.h>
#include <math.h> // fabs()
#include <HTTPClient.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
#include <Adafruit_TSL2561_U.h>
#include "bmm150.h"
#include "bmm150_defs.h"
const char* ssid = "Velxio-GUEST";
const char* pass = "";
const int wifiChannel = 6; // wymuszony kanal - pomija skanowanie sieci
HTTPClient http;
const char* serverURL = "http://kshyhoo.eu/weather/update.php";
// Prosty "sekret" chroniacy endpoint przed przypadkowym albo zlosliwym nadpisaniem danych przez kogos innego, kto zgadnie adres URL. Musi byc identyczny z wartoscia sprawdzana w update.php
const char* apiToken = "kshyhoo";
const unsigned long sendInterval = 5000; // co ile ms wysylac dane
// GLOBALNE ZMIENNE STANU (aktualizowane WYLACZNIE w sendTask)
float angleDeg = NAN; // kat choragiewki z AS5600 (0-360)
float stationHeadingDeg = NAN; // azymut stacji z BMM150 (0-360)
float windDeg = NAN; // prawdziwy kierunek wiatru (0-360)
float bmeTempC = NAN;
float bmePressureHpa = NAN;
float bmeHumidityPct = NAN;
float lightLux = NAN;
float uvIndex = NAN;
float waterLvl = NAN; // poziom wody [cm]
float d7sSi = NAN; // intensywnosc wibracji [SI]
float d7sPga = NAN; // przyspieszenie chwilowe PGA [m/s^2]
float windSpeedMps = 0; // predkosc wiatru z impulsow (liczona w loop)
#define SDA_PIN 23
#define SCL_PIN 22
// KIERUNEK WIATRU (AS5600)
#define WIND_I2C_AD