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.
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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.




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Motor DC o Motor de pasos
An interactive Arduino Uno circuit simulation you can run free in your browser on Velxio, by albertoarangurenp.
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
// --- Dirección I2C del LCD ---
LiquidCrystal_I2C lcd(0x27, 16, 2);
// --- Asignación de Pines (Panel de 5 Botones) ---
const int btnUp = 2; // Incrementar (+)
const int btnDown = 3; // Decrementar (-)
const int btnModo = 4; // Cambiar Modo / Menú
const int btnFreqVel = 8; // Frecuencia / Velocidad
const int btnAutoSweep = 11; // Auto-Sweep (Barrido Automático)
// --- Pines de Potencia ---
const int pinSTEP = 5; // A4988 STEP
const int pinDIR = 6; // A4988 DIR
const int pinEN = 7; // A4988 ENABLE
const int pinPWM_Apertura = 9; // MOSFET 1 / BTS7960 (Timer 1 - Canal A) -> OUT-A / LED Amarillo
const int pinPWM_Cierre = 10; // MOSFET 2 / BTS7960 (Timer 1 - Canal B) -> OUT-B / LED Rojo
// --- Variables de Estado y Menú ---
int modoActual = 0; // 0: Menú, 1: IAC 4P, 2: IAC 3P, 3: IAC 2P
int opcionMenu = 0; // 0: IAC 4P | 1: IAC 3P | 2: IAC 2P
// Parámetros IAC 4 Pines
int retardoPaso4P = 2000; // 4000us (Lento), 2000us (Medio), 1000us (Rápido)
int indiceVel4P = 1; // 0: Lento, 1: Medio, 2: Rápido
const char* nombresVel4P[] = {"Lent", "Med ", "Ráp "};
// Parámetros IAC 3P y 2P (PWM)
int porcentajePWM = 50; // 0% a 100%
int indiceFreqPWM = 1; // 0: 100Hz, 1: 150Hz, 2: 200Hz, 3: 300Hz
const int freqsPWM[] = {100, 150, 200, 300};
// Variables Auto-Sweep
bool enAutoSweep = false;
int sweepDir = 1; // 1: Incrementando, -1: Decrementando
unsigned long ultimoPasoSweep = 0;
// Declaración previa de funciones
void apagarSalidas();
void configurarTimer1_PWM(int frecuenciaHz);
void mostrarPantalla();
void ejecutarSweep4P();
void ejecutarSweepPWM();
void darPasoA4988();
void actualizarPWM();
void actualizarLineaPWM();
void setup() {
pinMode(btnUp, INPUT_PULLUP);
pinMode(btnDown, INPUT_PULLUP);
pinMode(btnModo, INPUT_PULLUP);
pinMode(btnFreqVel, INPUT_PULLUP);
pinMode(btnAutoSweep, INPUT_PULLUP);
pinMode(pinSTEP, OUTPUT);
pinMode(pinDIR, OUTPUT);
pinMode(pinEN, OUTPUT);
pinMode(pinPWM_Apertura, OUTPUT);
pinMode(pinPWM_Cierre, OUTPUT);
apagarSalidas();
lcd.init();
lcd.backlight();
configurarTimer1_PWM(freqsPWM[indiceFreqPWM]); // Frecuencia por defecto 150Hz
mostrarPantalla();
}
void loop() {
// =========================================================
// 1. LECTURA DEL BOTÓN DE MODO / MENÚ
// =========================================================
if (digitalRead(btnModo) == LOW) {
delay(180);
enAutoSweep = false;
if (modoActual == 0) {
modoActual = opcionMenu + 1; // 1: 4P, 2: 3P, 3: 2P
if (modoActual == 1) {
digitalWrite(pinEN, LOW); // Habilitar A4988
} else {
porcentajePWM = 50;
actualizarPWM();
}
} else {
apagarSalidas();
modoActual = 0;
}
mostrarPantalla();
while (digitalRead(btnModo) == LOW);
}
// =========================================================
// 2. LECTURA DEL BOTÓN FREQ / VEL
// ==============================