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 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.
An interactive ESP32-C3 circuit simulation you can run free in your browser on Velxio, by edelarosagon.
// ============================================================
// A R K A N O I D R E T R O - ESP32-C3 + ILI9341 + Touch
// ============================================================
// Pantalla: ILI9341 320x240 por SPI de hardware (FSPI)
// Touch: XPT2046 resistivo, compartiendo el mismo bus SPI
//
// IMPORTANTE - CONFLICTO DE PINES:
// En tus dos sketches anteriores, TFT_CS y T_CS eran el mismo
// pin (7). Ambos chips pueden compartir SCK/MISO/MOSI, pero
// cada uno necesita su propio CS. Aqui el touch usa el pin 2.
// Si ese pin esta ocupado en tu placa, cambia TOUCH_CS abajo.
// ============================================================
#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <XPT2046_Touchscreen.h>
// ---------- Pines TFT ----------
#define TFT_SCK 4
#define TFT_MISO 5
#define TFT_MOSI 6
#define TFT_CS 7
#define TFT_DC 3
#define TFT_RST 10
// ---------- Pin Touch (CS propio, resto del bus compartido) ----------
#define TOUCH_CS 2
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);
XPT2046_Touchscreen ts(TOUCH_CS);
// ---------- Calibracion del touch ----------
// Toca las 4 esquinas viendo el Monitor Serial y ajusta estos 4 numeros.
// Si el eje sale invertido o cruzado, cambia los flags SWAP/INVERT.
const int TS_MIN_X = 200, TS_MAX_X = 3900;
const int TS_MIN_Y = 200, TS_MAX_Y = 3900;
const bool TS_SWAP_XY = true; // pantalla en landscape suele necesitar swap
const bool TS_INVERT_X = false;
const bool TS_INVERT_Y = false;
// ---------- Paleta retro ----------
#define COL_BG ILI9341_BLACK
#define COL_PADDLE 0x07FF // cian neon
#define COL_BALL 0xFFE0 // amarillo
#define COL_TEXT 0x07FF
#define COL_LIVES 0xF800 // rojo
#define COL_WIN 0x07E0 // verde
const uint16_t rowColors[5] = {
0xF800, // rojo
0xFD20, // naranja
0xFFE0, // amarillo
0x07E0, // verde
0x07FF // cian
};
// ---------- Geometria del campo ----------
const int SCREEN_W = 320;
const int SCREEN_H = 240;
const int PADDLE_W = 50;
const int PADDLE_H = 8;
const int PADDLE_Y = SCREEN_H - 20;
const int BALL_R = 4;
const int BRICK_ROWS = 5;
const int BRICK_COLS = 10;
const int BRICK_W = 30;
const int BRICK_H = 12;
const int BRICK_GAP = 2;
const int BRICK_TOP = 30;
const int BRICK_LEFT = (SCREEN_W - (BRICK_COLS * (BRICK_W + BRICK_GAP))) / 2;
bool brickAlive[BRICK_ROWS][BRICK_COLS];
// ---------- Estado del juego ----------
enum GameState { START_SCREEN, PLAYING, LEVEL_CLEAR, GAME_OVER };
GameState state = START_SCREEN;
int paddleX, paddleXOld;
float ballX, ballY, ballDX, ballDY;
int ballXOld, ballYOld;
int score = 0;
int lives = 3;
int level = 1;
int bricksLeft = 0;
unsigned long lastFrame = 0;
const int FRAME_MS = 16; // ~60 fps logico
// ============================================================
// SETUP
// ============================================================
void setup() {
Serial.begin(115200);
SPI.begin(TFT_SC