LOLIN S2 mini

Board
by LOLIN (WEMOS)lolin-s2-mini≈ cheap (under ~$15)
Verify my boardCompareEdit on GitHub
Flash this board — 2 firmware options · Known good
LOLIN S2 mini pinout
Pinout

Specifications

Radiosinherited from ESP32-S2

Wi-Fi
Wi-Fi 4 · 2.4 GHz
Bluetooth LE
none
802.15.4
no

USB

Native USB
yes
Connector
usb-c

Board

Form factor
lolin-mini
Dimensions
34.3 × 25.4 mm
Built onLOLIN S2 mini BoardESP32-S2 SoC

Thumb-sized bare-S2 board: ESP32-S2FN4R2 (4 MB flash, 2 MB PSRAM), USB-C, 27 IO, D1-mini-shield compatible footprint.

Firmware for this board

Known good

  • WLEDKnown goodhomeweb flasher
    Flash WLEDweb flasherknown-good

    Known good esp-atlas asserts this board↔firmware link at the shown trust tier — it does not guarantee your specific unit or the current firmware version. Flashing can erase keys/config and can brick the device. At your own risk.

Unverified

  • NerdMiner v2Unverifieddisplay
    Flash NerdMiner v2guided

    Unverified esp-atlas asserts this board↔firmware link at the shown trust tier — it does not guarantee your specific unit or the current firmware version. Flashing can erase keys/config and can brick the device. At your own risk.

Notes

  • Based on ESP32-S2FN4R2; 4 MB flash, 2 MB PSRAM
  • 27x digital I/O pins
  • Pin-compatible with LOLIN D1 mini shields
  • io.gpio_exposed=27 QUOTED: vendor page states "27x IO" (Features) and "Digital I/O Pins | 27" (Technical specs table); no enumerated GPIO pin-list/table is published in the spec table, so power_out is omitted
  • io.gpio_free=27 DERIVED: the vendor's own labeled pinout diagram (s2_mini_v1.0.0 silkscreen photo) enumerates exactly 27 header GPIO pads (1-18, 21, 33-40) -- matching the "27x IO" spec exactly. Of esp32-s2's soc.reserved_pins, strapping 0/45/46 and usb_flash_tied 19/20 are all absent from this pad list (GPIO19/20 are consumed internally by the board's native USB-C, and 45/46 by internal flash-voltage strapping), and the 2 MB PSRAM (ESP32-S2FN4R2, in-package) uses GPIO27-32 (SPI0 bus) which are likewise absent from the header -- so no reserved or onboard-consumed pin lands on an exposed pad: 27 - 0 = 27

Verify my board

Reads the connected chip over USB and checks it against what esp-atlas cites for LOLIN S2 mini — over Web Serial, no backend, nothing leaves your browser.

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Serial monitor

Not connected.