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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Arduino, ESP32, RP2040, STM32, ATtiny and Raspberry Pi, with SPICE analog solved alongside the firmware. Not a sandboxed mock.
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An interactive ESP32 circuit simulation you can run free in your browser on Velxio, by titanabg0.
#include <Wire.h>
#include <Adafruit_ADS1X15.h>
Adafruit_ADS1115 ads;
// Конфигурационни константи
const int DAC_PIN = 25; // ESP32 Хардуерен DAC изход (GPIO 25)
const float VOLTAGE_DIVIDER = 11.0; // Коефициент на делителя за V_in и V_sense: (100k + 10k) / 10k
const float R_SHUNT = 0.1f; // Шунтов резистор в оми (0.1 Ω)
// DAC параметри (8-битова резолюция: 0 до 255, съответстваща на 0V до ~3.3V)
int dacValue = 200; // Начална стойност на аналоговото напрежение (~1.65V)
void setup() {
Serial.begin(115200);
while (!Serial);
Serial.println("Initializing Electronic Load System with DAC control...");
// Инициализация на I2C шината за ESP32 (SDA = 21, SCL = 22)
Wire.begin(21, 22);
// Проверка за наличие на ADS1115
if (!ads.begin()) {
Serial.println("Error: ADS1115 not found! Check wiring.");
while (1);
}
// Задаване на усилване GAIN_ONE (обхват до ~4.096V)
ads.setGain(GAIN_ONE);
// Забележка: За вградения DAC на ESP32 (пинове 25/26) не е нужно
// специално задаване в setup(), функцията dacWrite управлява пина директно.
Serial.println("System initialized successfully!");
}
void loop() {
// 1. Подаване на реално аналогово напрежение към гейта през DAC (пин 25)
// Стойност от 0 до 255 подава между 0V и 3.3V на гейта на логическия MOSFET
dacWrite(DAC_PIN, dacValue);
// 2. Четене на каналите от ADS1115
int16_t rawA0 = ads.readADC_SingleEnded(0); // V_in (Входно напрежение с делител)
int16_t rawA1 = ads.readADC_SingleEnded(1); // V_sense (Kelvin sense с делител)
int16_t rawDiff = ads.readADC_Differential_2_3(); // Диференциално четене на шунта (A2 - A3)
// 3. Преобразуване на суровите данни във волтове
float voltageIn = (rawA0 * 0.125F / 1000.0) * VOLTAGE_DIVIDER;
float voltageSense = (rawA1 * 0.125F / 1000.0) * VOLTAGE_DIVIDER;
// Падение на напрежение върху шунта (от диференциалния вход)
float shuntVoltage = rawDiff * 0.125F / 1000.0;
if (shuntVoltage < 0.0f) shuntVoltage = 0.0f;
// 4. Инженерни изчисления
// Ток през веригата (I = V_shunt / R_shunt)
float current = shuntVoltage / R_SHUNT;
// Изчисление на V_DS (Входно напрежение минус падението върху шунта)
float vDs = voltageIn - shuntVoltage;
if (vDs < 0.0f) vDs = 0.0f;
// Разсеяна мощност върху MOSFET-а във Ватове (P = V_DS * I)
float powerMosfet = vDs * current;
// Ефективно съпротивление на канала (R_DS = V_DS / I)
float mosfetResistance = (current > 0.001f) ? (vDs / current) : 0.0f;
// 5. Извеждане на актуалните данни в Serial конзолата
Serial.print("DAC: "); Serial.print(dacValue);
Serial.print(" | V_in: "); Serial.print(voltageIn, 2);
Serial.print("V | V_sense: "); Serial.print(voltageSense, 2);
Serial.print("V | I: "); Serial.print(current, 3);
Serial.print("A | V_DS: "); Serial.print(vDs, 2);
Serial.print("V | P_MOS: "); Serial.print(powerMosfet, 2);
Serial.print("W | R_DS: "); Se