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.
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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.
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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.
一个在SSD1306 OLED上显示计数和计算值的ESP32项目。
An interactive ESP32 circuit simulation you can run free in your browser on Velxio, by wsss.
// ============================================================================
// ESP32 — SSD1306 128x64 OLED
// 恐龙游戏 + 计费进度条 + 硬币动画 + 云池 + 仙人掌密度宏
// ============================================================================
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <WiFi.h>
#include <time.h>
Adafruit_SSD1306 display(128, 64, &Wire, -1);
// ==================== WiFi & NTP ====================
const char* ssid = "zhidian_502";
const char* password = "zhidian@999";
const char* ntpServer = "pool.ntp.org";
const long gmtOffset_sec = 8 * 3600;
const int daylightOffset_sec = 0;
// ==================== 计费参数 ====================
#define PAY_1 5600.0f
#define PAY_2 23.0f
#define PAY_3 7.5f
#define PAY_S (PAY_1 / PAY_2 / PAY_3 / 3600.0f)
#define COIN_TRIGGER 0.01f
// ==================== 时间节点 ====================
#define MORNING_HOUR 9
#define MORNING_MIN 0
#define NOON_HOUR 12
#define NOON_MIN 0
#define AFTERNOON_HOUR 13
#define AFTERNOON_MIN 30
#define PROGRESS_END_HOUR 18
#define PROGRESS_END_MIN 0
// ==================== 屏幕页布局 ====================
#define PAGE_TITLE 0
#define PAGE_CLOUD 1
#define PAGE_DINO_TOP 5
#define PAGE_GROUND 6
#define PAGE_PROGRESS 7
#define COIN_PAGE_LOW PAGE_DINO_TOP
#define COIN_PAGE_HIGH 2
// ============================================================================
// ★ 云参数(可调)
// ============================================================================
// 云密度:目标同时存在的云数量(值越大云越多)
#define CLOUD_DENSITY 4
// 生成间隔基准帧数:实际间隔 = BASE / DENSITY
// 数值越小 → 生成越快 → 屏幕上的云越多
#define CLOUD_SPAWN_BASE 100
// 云池容量(硬上限,需 ≥ CLOUD_DENSITY)
#define CLOUD_MAX 8
// 云的移动速度(像素/帧)
#define CLOUD_SPEED 2
// 每次生成时的随机抖动百分比(0~100,50 表示 ±50%)
#define CLOUD_SPAWN_JITTER 50
// ============================================================================
// ★ 仙人掌参数(可调)
// ============================================================================
// 仙人掌密度百分比(相对原始 100%)
#define CACTUS_DENSITY_PERCENT 230
// 基准生成间隔帧数(对应密度 100% 时)
#define CACTUS_SPAWN_BASE 40
// 实际生成间隔(帧),由基准值和密度百分比换算
#define CACTUS_SPAWN_INTERVAL ((CACTUS_SPAWN_BASE * 100) / CACTUS_DENSITY_PERCENT)
// ==================== 自动跳跃参数 ====================
#define JUMP_TRIGGER_X 48
#define COIN_TRIGGER_X_MIN 56
#define COIN_TRIGGER_X_MAX 80
#define DOUBLE_JUMP_H_THRESHOLD 15
#define DOUBLE_JUMP_DANGER_MIN 16
#define DOUBLE_JUMP_DANGER_MAX 40
#define DOUBLE_JUMP_BMP_START 4
// ============================================================================
// ★ 冲撞触发阈值
// ============================================================================
#define CHARGE_GAP_FRONT_LOW 90
#define CHARGE_GAP_BEHIND_HIGH 120
// ============================================================================
// ★ 低硬币跳跃危险区
// =