Wemos Lolin32 Lite Simulator
The compact ESP32 with a LiPo charger, free in your browser
Simulate the Wemos Lolin32 Lite in your browser for free: the 26-pin ESP32 running Arduino C++, MicroPython or ESP-IDF on an in-browser emulator, with GPIO, I2C, SPI and UART wired to a live canvas and WiFi against a virtual access point.
Free plan · No install, no account · Runs in your browser
Wemos Lolin32 Lite at a glance
The Lolin32 Lite is a compact ESP32 in the Lolin footprint with a LiPo charger on board: the same dual-core Xtensa chip and the same simulator support as the DevKit V1, in 26 pins. Pick it when the physical board you are prototyping for is this one; the code side is identical to any other classic ESP32, so examples written for the DevKit run unchanged as long as the pins exist here.
- Processor
- ESP32, dual Xtensa LX6 at 240 MHz
- Memory
- 520 KB SRAM · 4 MB flash
- Emulation
- esp32js (in-browser)
- Languages
- Arduino C++ · MicroPython · ESP-IDF
- Made by
- Wemos
- Plan
- Free
What you can do with the Wemos Lolin32 Lite simulator
The board on the canvas is the real thing as far as your code is concerned: the same pins, the same buses, the same peripherals, wired to the same 100+ sensors, displays and actuators every other Velxio board talks to.
Arduino C++ sketches
Write a sketch in the Monaco editor with library completion, compile it against the board's own Arduino core and run the real firmware binary. The Serial Monitor is the USB port.
MicroPython
Switch the board to MicroPython from the toolbar and run main.py against the same circuit. Drivers are plain .py files in the workspace, copied onto the board's filesystem before your script starts.
ESP-IDF projects
Build a full ESP-IDF project (v5.5.4) with FreeRTOS tasks, sdkconfig and components, and run it on the emulated chip without a devkit on your desk.
WiFi against a virtual access point
The emulator advertises the Velxio-GUEST network: HTTP servers, MQTT clients and NTP sync in your sketch connect and answer, without leaving the browser.
GPIO, PWM and ADC
Drive LEDs, relays and servos, read buttons and potentiometers, dim with PWM. Every pin follows the board's real pin map, so what works here works on the hardware.
I2C, SPI and UART
Talk to OLEDs, IMUs, ADCs, RTCs and SD cards over the buses the board really has. Bus traffic runs through emulated peripherals, not through a shortcut.
Serial Monitor
USB CDC serial reaches the Serial Monitor at the sketch's baud rate, with input, timestamps and a plotter.
SPICE analog parts
Op-amps, transistors, regulators and passives simulate in real time with ngspice in the browser; the board's pins drive them and read the solved voltages back.
Wemos Lolin32 Lite examples
This board has no examples of its own yet. These are written for the ESP32 DevKit devkit, which uses the same chip: they run on the Wemos Lolin32 Lite after a pin map check.
ESP32: SSD1306 OLED (4-pin I2C)Drive the cheap 4-pin SSD1306 OLED module (GND/VCC/SCL/SDA) over I2C from an ESP32 (SDA=21, SCL=22).
ESP32 + MicroPython: use an external libraryHow a MicroPython project uses a library in Velxio: there is no requirements.txt and no package manager — the driver is a .py file in the workspace. Every file here is copied onto the board's filesystem before main.py runs, so `import ssd1306` picks up the ssd1306.py next to it and draws on the wired OLED. The toolbar's Library Manager installs ARDUINO libraries and has no effect in MicroPython mode.
ESP32: Pure ESP-IDF BlinkBlink an LED from a pure ESP-IDF project — app_main(), FreeRTOS delays and the GPIO driver, no Arduino core. Pick "ESP-IDF" in the language selector to write more projects like this.
ESP32: Stepper + A4988Spin a bipolar stepper motor from an ESP32 through an A4988 driver (STEP = GPIO26, DIR = GPIO27).
ESP32 Blink LEDBlink the built-in LED on GPIO2 and an external red LED on GPIO4. Verifies ESP32 emulation is working.
ESP32 NeoPixel coloursThe same pixel on an ESP32. Adafruit_NeoPixel drives it through the RMT peripheral here, so the pad never toggles at bit rate and the engine hands the decoded frame to the part.
ESP32 Serial EchoESP32 reads from Serial and echoes back. Demonstrates multi-UART and Serial Monitor integration.
ESP32: 7-Segment CounterCount 0–9 on a 7-segment display driven from GPIO 12, 13, 14, 25, 26, 27, 32 on the ESP32.
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Frequently asked questions
- Do ESP32 DevKit examples run on the Lolin32 Lite?
- Yes, as long as the GPIOs they use exist on the Lite's 26 pins. The examples on this page are the DevKit's; place a Lolin32 Lite instead and check the pin map before wiring.
- Is the battery charger simulated?
- No. The charger and the battery connector are drawn on the board but not modelled; the board is powered as if from USB. Everything on the GPIO side runs.
- Is the Wemos Lolin32 Lite simulator free?
- Yes. The Wemos Lolin32 Lite runs on the free plan: open the editor, place the board and press Run. No install and no account are needed, and Velxio's editor and simulator core are open source under the GNU AGPLv3.
- Which languages can I use on the Wemos Lolin32 Lite?
- Arduino C++, MicroPython, ESP-IDF. The language is switched from the toolbar; the circuit on the canvas stays the same.
Ready to simulate the Wemos Lolin32 Lite?
Open the editor, place the Wemos Lolin32 Lite from the picker, wire what you need and press Run.
Launch the Wemos Lolin32 Lite simulator →