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 raise the daily AI quota and unlock the Linux boards, private projects and the offline desktop app.
Discover the simulator + light AI help.
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.
Proyek buzzer yang memainkan pola Morse SOS menggunakan tone()
An interactive Arduino Uno circuit simulation you can run free in your browser on Velxio, by belvaclairina006.
// --- Konfigurasi Pin ---
const int pinTombol = 2; // Push Button
const int pinBuzzer = 8; // Buzzer
const int pinLedHijau = 12; // Indikator Standby (Hijau)
const int pinLedMerah = 13; // Indikator Alarm SOS (Merah)
const int pinPotensio = A0; // Potensiometer Pengatur Kecepatan
// --- Variabel Status & Debounce ---
bool alarmAktif = false;
int statusTombolTerakhir = HIGH;
unsigned long waktuDebounceTerakhir = 0;
const unsigned long jedaDebounce = 50;
const int frekuensiBuzzer = 1000; // Frekuensi suara buzzer (Hz)
void setup() {
pinMode(pinBuzzer, OUTPUT);
pinMode(pinLedMerah, OUTPUT);
pinMode(pinLedHijau, OUTPUT);
// Menggunakan internal pull-up: tombol aktif saat bernilai LOW
pinMode(pinTombol, INPUT_PULLUP);
// Pastikan kondisi awal: Buzzer mati, LED hijau menyala
digitalWrite(pinBuzzer, LOW);
noTone(pinBuzzer);
digitalWrite(pinLedHijau, HIGH);
digitalWrite(pinLedMerah, LOW);
}
// Fungsi debounce tombol tanpa menghentikan program (non-blocking)
void cekTombol() {
int bacaan = digitalRead(pinTombol);
if (bacaan != statusTombolTerakhir) {
waktuDebounceTerakhir = millis();
}
if ((millis() - waktuDebounceTerakhir) > jedaDebounce) {
static int statusTombolSekarang = HIGH;
if (bacaan != statusTombolSekarang) {
statusTombolSekarang = bacaan;
// Saat tombol ditekan (menghubungkan ke GND)
if (statusTombolSekarang == LOW) {
alarmAktif = !alarmAktif; // Toggle status ON/OFF
}
}
}
statusTombolTerakhir = bacaan;
}
// Fungsi menyalakan buzzer DAN LED merah secara bersamaan
bool bunyiDanLampu(int durasi) {
tone(pinBuzzer, frekuensiBuzzer); // Buzzer BERBUNYI di sini
digitalWrite(pinLedMerah, HIGH); // LED Merah Menyala
unsigned long mulai = millis();
while (millis() - mulai < (unsigned long)durasi) {
cekTombol();
if (!alarmAktif) {
noTone(pinBuzzer);
digitalWrite(pinLedMerah, LOW);
return false;
}
}
noTone(pinBuzzer);
digitalWrite(pinLedMerah, LOW);
return true;
}
// Fungsi jeda waktu (hening/mati) antar kedipan SOS yang tetap responsif terhadap tombol
bool jedaResponsif(int durasi) {
noTone(pinBuzzer); // Pastikan buzzer mati saat jeda
unsigned long mulai = millis();
while (millis() - mulai < (unsigned long)durasi) {
cekTombol();
if (!alarmAktif) return false;
}
return true;
}
void loop() {
cekTombol();
if (!alarmAktif) {
// --- MODE STANDBY ---
noTone(pinBuzzer); // Buzzer dipastikan MATI
digitalWrite(pinLedHijau, HIGH); // LED Hijau Menyala (Siaga)
digitalWrite(pinLedMerah, LOW); // LED Merah Padam
} else {
// --- MODE ALARM AKTIF (SOS) ---
digitalWrite(pinLedHijau, LOW); // LED Hijau Padam
// Baca potensiometer untuk mengatur kecepatan ritme SOS
int nilaiPot = analogRead(pinPotensio);
int durasiTitik = map(nilaiPot, 0, 1023, 80, 400); // 80ms s.d 400ms
int dur