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wemos-esp32-s2-mini

5 min read

Important Note

This entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!

WEMOS ESP32-S2 Mini Development Board

Details

Description

Compact WiFi-enabled development board based on the ESP32-S2FN4R2 chip. Features native USB support, generous memory allocation, and compatibility with LOLIN D1 Mini shields. Perfect for IoT projects requiring WiFi connectivity with USB HID capabilities. Comes pre-loaded with MicroPython firmware.

Specifications

  • Microcontroller: ESP32-S2FN4R2
  • Architecture: Xtensa LX7 32-bit single-core
  • Clock Speed: 240MHz
  • Operating Voltage: 3.3V
  • Flash Memory: 4MB
  • PSRAM: 2MB
  • Dimensions: 34.3mm x 25.4mm
  • Weight: 2.4g

Images

Product Photos

WEMOS ESP32-S2 Mini Development Board - Top View

WEMOS ESP32-S2 Mini Development Board - Bottom View

Pinout Diagrams

ESP32-S2 Mini Pinout Diagram - Official

ESP32-S2 Mini Pinout Diagram - Detailed

Features

  • ESP32-S2FN4R2: Single-core WiFi microcontroller with native USB
  • Native USB: Built-in USB support - can act as keyboard/mouse, MIDI device, mass storage
  • Type-C USB: Modern connector for programming and power
  • Rich Memory: 4MB Flash + 2MB PSRAM for complex applications
  • 27 GPIO Pins: Extensive I/O capabilities
  • D1 Mini Compatible: Works with existing LOLIN D1 Mini shields
  • Multiple Programming: MicroPython, Arduino, CircuitPython, ESP-IDF support
  • Default Firmware: Ships with MicroPython pre-installed

Pin Configuration

  • Digital I/O: 27 GPIO pins
  • Analog Inputs: 20 pins (12-bit ADC)
  • Analog Outputs: 2 pins (8-bit DAC)
  • PWM: All GPIO pins support PWM
  • I2C: Hardware I2C support
  • SPI: Hardware SPI support
  • UART: Hardware UART support
  • USB OTG: Native USB On-The-Go support

Detailed Pinout

Left Side (Top to Bottom)

  • 3V3: 3.3V power output
  • GND: Ground
  • GPIO1: Digital I/O, ADC1_CH0, Touch1
  • GPIO2: Digital I/O, ADC1_CH1, Touch2
  • GPIO3: Digital I/O, ADC1_CH2, Touch3
  • GPIO4: Digital I/O, ADC1_CH3, Touch4
  • GPIO5: Digital I/O, ADC1_CH4, Touch5
  • GPIO6: Digital I/O, ADC1_CH5, Touch6
  • GPIO7: Digital I/O, ADC1_CH6, Touch7
  • GPIO8: Digital I/O, ADC1_CH7, Touch8
  • GPIO9: Digital I/O, ADC1_CH8, Touch9
  • GPIO10: Digital I/O, ADC1_CH9, Touch10
  • GPIO11: Digital I/O, ADC2_CH0, Touch11
  • GPIO12: Digital I/O, ADC2_CH1, Touch12
  • GPIO13: Digital I/O, ADC2_CH2, Touch13
  • GPIO14: Digital I/O, ADC2_CH3, Touch14

Right Side (Top to Bottom)

  • 5V: 5V power input (from USB)
  • GND: Ground
  • GPIO15: Digital I/O, ADC2_CH4, Touch15, XTAL_32K_P
  • GPIO16: Digital I/O, ADC2_CH5, Touch16, XTAL_32K_N
  • GPIO17: Digital I/O, ADC2_CH6, Touch17, DAC_1
  • GPIO18: Digital I/O, ADC2_CH7, Touch18, DAC_2
  • GPIO19: Digital I/O, ADC2_CH8, Touch19, USB_D-
  • GPIO20: Digital I/O, ADC2_CH9, Touch20, USB_D+
  • GPIO21: Digital I/O, RTC_GPIO0
  • GPIO33: Digital I/O, XTAL_32K_P (if external crystal)
  • GPIO34: Digital I/O, XTAL_32K_N (if external crystal)
  • GPIO35: Digital I/O
  • GPIO36: Digital I/O
  • GPIO37: Digital I/O
  • GPIO38: Digital I/O
  • GPIO39: Digital I/O
  • GPIO40: Digital I/O
  • GPIO41: Digital I/O
  • GPIO42: Digital I/O

Special Functions

  • GPIO19/GPIO20: USB D-/D+ (native USB)
  • GPIO17/GPIO18: DAC outputs (8-bit)
  • GPIO1-GPIO14: Touch-sensitive pins
  • All GPIO: PWM capable
  • ADC1: GPIO1-GPIO10 (12-bit ADC)
  • ADC2: GPIO11-GPIO20 (12-bit ADC, shared with WiFi)

Power Specifications

  • Operating Voltage: 3.3V
  • Input Voltage: 5V (USB-C) or 3.3V (VCC pin)
  • Current Consumption:
    • Active (WiFi): ~80-120mA
    • Light Sleep: ~1-2mA
    • Deep Sleep: ~10-20μA
  • Power Supply: Built-in 3.3V regulator

Wireless Capabilities

WiFi

  • Standards: 802.11 b/g/n (2.4GHz)
  • Modes: Station, Access Point, Station+AP
  • Security: WEP, WPA, WPA2, WPA3
  • Range: Standard WiFi range

Applications

  • IoT sensor nodes with WiFi connectivity
  • USB HID devices (keyboard, mouse, MIDI)
  • WiFi-enabled automation projects
  • MicroPython learning and development
  • CircuitPython projects
  • Web servers and clients
  • MQTT clients and IoT gateways
  • Educational microcontroller projects

Programming

  • MicroPython: Default firmware, drag-and-drop programming
  • Arduino IDE: Full support with ESP32 board package
  • CircuitPython: Native support with USB drive functionality
  • ESP-IDF: Espressif development framework
  • USB Programming: No external programmer needed
  • Libraries: WiFi, HTTP, MQTT, USB HID libraries

Programming Examples

Arduino WiFi Example

#include <WiFi.h>
 
const char* ssid = "your-wifi-ssid";
const char* password = "your-wifi-password";
 
void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
 
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
 
  Serial.println("WiFi connected!");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}
 
void loop() {
  // Your code here
}

MicroPython Example

import network
import time
 
# Connect to WiFi
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect('your-wifi-ssid', 'your-wifi-password')
 
while not wlan.isconnected():
    print('Connecting to WiFi...')
    time.sleep(1)
 
print('WiFi connected!')
print('IP address:', wlan.ifconfig()[0])

USB HID Example (Arduino)

#include "USB.h"
#include "USBHIDKeyboard.h"
 
USBHIDKeyboard Keyboard;
 
void setup() {
  Keyboard.begin();
  USB.begin();
}
 
void loop() {
  Keyboard.print("Hello from ESP32-S2!");
  delay(5000);
}

D1 Mini Ecosystem

  • Shield Compatible: Works with LOLIN D1 Mini shields
  • Form Factor: Standard D1 Mini pinout and dimensions
  • Accessories: Large ecosystem of compatible shields and sensors
  • Community: Extensive D1 Mini community support

Advantages

  • Native USB: Advanced USB functionality built-in
  • Rich Memory: 4MB Flash + 2MB PSRAM for complex projects
  • Shield Compatible: Leverage existing D1 Mini ecosystem
  • Multi-Language: Support for multiple programming environments
  • Cost Effective: Excellent price-to-performance ratio
  • Easy Development: MicroPython pre-installed for quick start

Hardware Features

  • Type-C USB: Modern, reversible connector
  • Reset Button: Convenient program restart
  • Boot Button: Enter bootloader mode
  • User LED: Built-in status indicator
  • Antenna: PCB antenna for WiFi connectivity

Comparison with Other ESP32-S2 Boards

  • vs Adafruit QT Py ESP32-S2: Larger size but more GPIO pins and shield compatibility
  • vs ESP32-S2-DevKitC: More compact, shield-compatible form factor
  • vs ESP32-S3: Single-core vs dual-core, no Bluetooth but native USB

Notes

  • Single-core ESP32-S2 (not dual-core like ESP32 classic)
  • No Bluetooth support (WiFi only)
  • Native USB enables advanced interfacing capabilities
  • 4MB Flash + 2MB PSRAM allows for complex applications
  • Perfect for IoT projects requiring WiFi connectivity
  • D1 Mini shield compatibility expands functionality
  • MicroPython firmware makes it beginner-friendly
  • Excellent for learning ESP32-S2 architecture

Default Firmware

  • MicroPython: Pre-installed for immediate use
  • REPL Access: Interactive Python shell via USB
  • File System: Access files via USB mass storage
  • WiFi Libraries: Built-in WiFi connectivity support

Tags

microcontroller, esp32-s2, wifi, wemos, s2-mini, usb-c, d1-mini-compatible, iot, micropython, circuitpython

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