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.




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.
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Private projects, BOM and schematic exports, GitHub Sync and the offline desktop app, 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. Paid plans unlock the Linux and STM32 boards, WiFi and the offline desktop app. 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.
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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 circuit simulation you can run free in your browser on Velxio, by ryanankar.
// #include <Wire.h>
// #include <LiquidCrystal_I2C.h>
// #include <Digital_Light_TSL2561.h>
// #define LED_MERAH 2
// #define LED_HIJAU 5
// #define SPEAKER 19
// LiquidCrystal_I2C lcd(0x27, 16, 2);
// unsigned long lastValidLux = 0;
// void setup() {
// Serial.begin(115200);
// Wire.begin(21, 22);
// TSL2561.init();
// lcd.init();
// lcd.backlight();
// pinMode(LED_MERAH, OUTPUT);
// pinMode(LED_HIJAU, OUTPUT);
// pinMode(SPEAKER, OUTPUT);
// }
// void loop() {
// unsigned long luxValue = TSL2561.readVisibleLux();
// if (luxValue == 0 && lastValidLux > 500) {
// luxValue = 40000;
// } else if (luxValue > 0) {
// lastValidLux = luxValue;
// }
// Serial.print("Intensitas Cahaya: ");
// Serial.print(luxValue);
// Serial.println(" Lux");
// lcd.setCursor(0, 0);
// lcd.print("Cahaya: ");
// lcd.print(luxValue);
// lcd.print(" lx ");
// if (luxValue > 5000) {
// digitalWrite(LED_HIJAU, HIGH);
// digitalWrite(LED_MERAH, LOW);
// noTone(SPEAKER);
// lcd.setCursor(0, 1);
// lcd.print("Status: CERAH ");
// } else {
// digitalWrite(LED_HIJAU, LOW);
// digitalWrite(LED_MERAH, HIGH);
// tone(SPEAKER, 1500);
// lcd.setCursor(0, 1);
// lcd.print("Status: GELAP ");
// }
// delay(300);
// }
/*************************************************************
Project IoT: Sensor Cahaya, LCD, LED, Speaker & Blynk IoT
ESP32 Pin Mapping:
- Sensor Cahaya & LCD (I2C): SDA -> D21, SCL -> D22
- Grove Speaker: SIG -> D19
- LED Merah & Hijau: D18 & D5 (Contoh pin digital tambahan untuk LED)
*************************************************************/
#define BLYNK_TEMPLATE_ID "TMPL6VY-TOzBZ"
#define BLYNK_TEMPLATE_NAME "Quickstart Device"
#define BLYNK_AUTH_TOKEN "0NIE1QAp2ZKNjfbqnvRLnpUDAhZJU7z7"
#define BLYNK_PRINT Serial
#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
// WiFi Credentials
char ssid[] = "Top Singko"; // Ganti dengan nama WiFi Anda
char pass[] = "ragatmas"; // Ganti dengan password WiFi Anda
BlynkTimer timer;
// Inisialisasi LCD I2C (Alamat 0x27 atau 0x3F, ukuran 16x2)
LiquidCrystal_I2C lcd(0x27, 16, 2);
// Definisi Pin Komponen
const int SPEAKER_PIN = 19;
const int LED_MERAH = 2; // Sesuaikan dengan rangkaian Anda
const int LED_HIJAU = 5; // Sesuaikan dengan rangkaian Anda
// Variabel untuk menyimpan nilai sensor cahaya
int lightValue = 0;
// Fungsi untuk membaca sensor cahaya (Simulasi / Integrasi I2C)
void readLightSensor() {
// Contoh pembacaan I2C sensor cahaya (ganti dengan fungsi pustaka spesifik sensor Anda)
// Di sini kita gunakan pembacaan dummy atau pembacaan register I2C
Wire.beginTransmission(0x23); // Contoh alamat I2C sensor cahaya umum (misal BH1750)
Wire.endTransmission();
// Simulasi nilai cahaya (0 - 1023 atau Lux)
// Anda dapat menggantinya sesuai fungsi pembacaan se