LOLIN C3 mini

Board
by LOLIN (WEMOS)lolin-c3-mini≈ cheap (under ~$15)
Verify my boardCompareEdit on GitHub
Flash this board — 1 firmware option · Unverified
LOLIN C3 mini pinout
Pinout

Specifications

Radiosinherited from ESP32-C3

Wi-Fi
Wi-Fi 4 · 2.4 GHz
Bluetooth LE
BLE 5
Bluetooth Classic
no
802.15.4
no

USB

Native USB
yes
Connector
usb-c

Board

Form factor
lolin-mini
Dimensions
34.3 × 25.4 mm

Display & extras

Extras
rgb-led
Built onLOLIN C3 mini BoardESP32-C3 SoC

Thumb-sized bare-C3 board: RISC-V ESP32-C3, 4 MB flash, USB-C, onboard WS2812B RGB LED, 12 IO.

Firmware for this board

Unverified

  • OpenMQTTGatewayUnverifiedhome
    Flash OpenMQTTGatewayguided

    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-C3, RISC-V single-core Wi-Fi + Bluetooth LE
  • 4 MB flash
  • 12x digital I/O pins
  • Onboard WS2812B addressable RGB LED
  • Weight: 2.6 g
  • ESP32-C3 has no PSRAM interface at all (chip datasheet lists no PSRAM/external-RAM support)
  • io.gpio_exposed=12 QUOTED: vendor page states "12x IO" (Features) and "Digital I/O Pins | 12" (Technical specs table); no enumerated GPIO pin-list/table is published in the spec table, so power_out is omitted
  • io.gpio_free=10 DERIVED: the vendor's own labeled pinout diagram (c3_mini_v2.1.0 silkscreen photo) enumerates exactly 12 header GPIO pads: TX/21, RX/20, 10, 8, 7, 6, A3/3, A2/2, A1/1, A0/0, A4/4, A5/5 -- matching the "12x IO" spec exactly. Of esp32-c3's soc.reserved_pins, strapping GPIO2 and GPIO8 are among them (2 pins); usb_flash_tied GPIO18/19 are not exposed; ESP32-C3 has no PSRAM to consume a pin. GPIO7 doubles as the onboard WS2812 RGB LED but remains header-exposed so it is not subtracted -- so 12 - 2 = 10

Verify my board

Reads the connected chip over USB and checks it against what esp-atlas cites for LOLIN C3 mini — over Web Serial, no backend, nothing leaves your browser.

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Serial monitor

Not connected.