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, 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.
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.
Projet de Fin d'Etudes
An interactive ESP32 circuit simulation you can run free in your browser on Velxio, by iyadh-jlassi01.
// ═══════════════════════════════════════════════════════════════
// TEST ÉVALUATION — Arduino Framework
// Métriques : Réactivité, Fiabilité, Consommation
// EV2 Jlassi Mohamed Iyadh
// ═══════════════════════════════════════════════════════════════
#include <Wire.h>
#include <MPU6050.h>
#include <Servo.h>
#include <ArduinoJson.h>
// ─── Broches ────────────────────────────────────────────────────
#define PIN_SDA 21
#define PIN_SCL 22
#define PIN_SERVO 25
#define PIN_BTN_START 14
#define PIN_BTN_EMERG 13
#define PIN_LED_INIT 33
#define PIN_LED_IDLE 26
#define PIN_LED_MANUAL 27
#define PIN_LED_EMERGENCY 32
// ═══════════════════════════════════════════════════════════════
// VARIABLES DE MESURE
// ═══════════════════════════════════════════════════════════════
// ── Réactivité ────────────────────────────────────────────────
unsigned long t_pid_debut = 0;
unsigned long t_pid_fin = 0;
unsigned long t_pid_precedent = 0;
unsigned long periode_pid = 0;
long jitter_pid = 0;
long jitter_max = 0;
long jitter_min = 99999;
float jitter_somme = 0;
unsigned long nb_cycles = 0;
unsigned long nb_cycles_conformes= 0;
unsigned long duree_pid_us = 0;
// ── Temps de réponse commande ─────────────────────────────────
unsigned long t_commande_recue = 0;
unsigned long t_actionneur = 0;
unsigned long delai_reponse = 0;
// ── Délai mise en sécurité ────────────────────────────────────
unsigned long t_urgence_detectee = 0;
unsigned long t_urgence_appliquee= 0;
unsigned long delai_securite = 0;
// ── Consommation (estimation CPU) ────────────────────────────
unsigned long t_cpu_actif = 0;
unsigned long t_boucle_debut = 0;
unsigned long t_boucle_fin = 0;
float taux_cpu = 0;
unsigned long nb_boucles = 0;
// ── Fiabilité ─────────────────────────────────────────────────
unsigned long nb_erreurs_imu = 0;
unsigned long nb_lectures_imu = 0;
// ─── État du drone ───────────────────────────────────────────────
enum DroneMode { INIT, IDLE, MANUAL, EMERGENCY };
DroneMode g_mode = INIT;
float g_roll=0, g_pitch=0, g_yaw=0;
float g_servo_angle=90;
int g_motor=0, g_heading=0, g_battery=100;
bool imuOK=false;
float Kp=1.5, Ki=0.01, Kd=0.5;
float pid_integral=0, pid_error_prev=0;
// ─── Matériel ────────────────────────────────────────────────────
MPU6050 imu;
Servo servoGouvernail;
// ─── Anti-rebond ─────────────────────────────────────────────────
bool bs_prev=HIGH, be_prev=HIGH;
unsigned long t_bs=0, t_be=0;
// ─── Timers planificateur ─────────────────────────────────────────
unsigned long t_imu=0, t_pid=0, t_tel=0, t_bat=0, t_saf=0;
unsigned long t_rapport=0;
// ═══════════════════════════════════════════════════════════════
// DÉCLARATIONS ANTICIPÉES ← CORRECTIF #1
// ═══════════════════════════════════════════════════════════════
void affic