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.
An interactive ESP32 circuit simulation you can run free in your browser on Velxio, by canenessefa32.
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <XPT2046_Touchscreen.h>
#include <Adafruit_AHTX0.h>
// =====================================================
// SEF TFT + TOUCH + AHT20
// ESP32 DevKit V1
// ILI9341 2.8" 320x240 Landscape
// XPT2046 Touch
// AHT20 Temperature + Humidity
// =====================================================
// =====================================================
// TFT PINLERI
// =====================================================
#define TFT_CS 5
#define TFT_RST 16
#define TFT_DC 17
#define TFT_SCK 18
#define TFT_MISO 19
#define TFT_MOSI 23
// =====================================================
// TOUCH PINLERI
// =====================================================
#define TOUCH_CS 13
#define TOUCH_IRQ 35
// =====================================================
// RGB LED
// =====================================================
#define LED_R 25
#define LED_G 26
#define LED_B 33
// =====================================================
// BUTONLAR
// =====================================================
#define FACE_BUTTON 4
#define CLOCK_BUTTON 27
#define ENTERTAINMENT_BUTTON 14
// =====================================================
// NESNELER
// =====================================================
Adafruit_ILI9341 tft(
TFT_CS,
TFT_DC,
TFT_RST
);
XPT2046_Touchscreen touch(
TOUCH_CS,
TOUCH_IRQ
);
Adafruit_AHTX0 aht;
// =====================================================
// EKRAN
// =====================================================
#define SCREEN_W 320
#define SCREEN_H 240
// =====================================================
// TOUCH KALIBRASYONU
// =====================================================
// Çalışan eksen düzenimiz:
#define TOUCH_X_MIN 200
#define TOUCH_X_MAX 3800
#define TOUCH_Y_MIN 200
#define TOUCH_Y_MAX 3800
// =====================================================
// SAYFALAR
// =====================================================
enum Page {
PAGE_HOME,
PAGE_MENU,
PAGE_ENVIRONMENT,
PAGE_CLOCK,
PAGE_ABOUT
};
Page currentPage = PAGE_HOME;
// =====================================================
// YUZLER
// =====================================================
enum FaceType {
NORMAL,
HAPPY,
SURPRISED,
SAD,
ANGRY,
CURIOUS,
COOL,
SHY,
SCARED,
TIRED,
SUSPICIOUS,
EXCITED
};
FaceType currentFace = NORMAL;
// =====================================================
// ORTAM
// =====================================================
float temperature = 0;
float humidity = 0;
bool ahtOK = false;
unsigned long lastSensorRead = 0;
const unsigned long SENSOR_INTERVAL = 2000;
// =====================================================
// SAAT
// =====================================================
int clockHour = 18;
int clockMinute = 30;
int clockSecond = 0;
unsigned long lastSecond = 0;
// ==================================