The NodeMCU ESP32-S 38-Pin Narrow Development Board (Micro-USB / Wi-Fi + Bluetooth + BLE) is a versatile, high-performance IoT development platform based on the Espressif ESP-WROOM-32 (ESP32-S) module. Powered by the dual-core 32-bit Xtensa LX6 microprocessor running at up to 240 MHz, it integrates 2.4 GHz Wi-Fi (802.11 b/g/n) and dual-mode Bluetooth (v4.2 BR/EDR and BLE). Designed in a slim, breadboard-friendly "Narrow" form factor, it leaves a full row of tie-points exposed on both sides of a standard solderless breadboard. Equipped with an onboard CP2102 USB-to-UART bridge, Micro-USB port, 3.3V low-dropout voltage regulator, and dual EN/BOOT buttons, it is widely used in smart home automation, industrial IoT telemetry, robotics, sensor nodes, and wireless edge computing.

Specifications

• Module Model: ESP-WROOM-32 / ESP32-S Module
• Core Processor: Dual-Core 32-bit Xtensa LX6 Microprocessor
• CPU Operating Frequency: Adjustable from 80 MHz up to 240 MHz (Up to 600 DMIPS)
• Internal SRAM: 520 KB
• Embedded Flash Memory: 4 MB (32 Mb) SPI Flash
• ROM: 448 KB (for booting and core functions)
• Board Form Factor: Narrow 38-Pin Breadboard-Friendly Layout (0.9-inch / 22.86mm row spacing)
• Wireless Connectivity:
  • Wi-Fi: 802.11 b/g/n (up to 150 Mbps) with WEP, WPA/WPA2-PSK (AES/TKIP)
  • Bluetooth: Bluetooth v4.2 BR/EDR and Bluetooth Low Energy (BLE)
• USB Interface & Bridge: Micro-USB Port with onboard Silicon Labs CP2102 USB-to-UART Bridge Controller
• Operating Supply Voltage:
  • Via Micro-USB: 5.0V DC
  • Via Vin Pin: 5.0V to 9.0V DC (Regulated down via onboard 3.3V LDO)
  • Logic / Core Operating Voltage: 3.3V DC (Strictly 3.3V I/O logic levels)
• Onboard Voltage Regulator: 3.3V LDO Regulator (AMS1117-3.3 / ME6211 supporting up to 800mA peak)
• General Purpose I/O (GPIO): Up to 30 usable GPIO pins with multi-function multiplexing
• Hardware Peripherals & Interfaces:
  • ADC: 12-bit SAR ADC up to 18 Channels (ADC1 and ADC2)
  • DAC: 2x 8-bit Digital-to-Analog Converters (DAC1 - GPIO25, DAC2 - GPIO26)
  • Capacitive Touch: 10x Capacitive Touch Sensing GPIO Channels
  • PWM: Up to 16 independent hardware PWM channels (LEDC module)
  • Serial UART: 3x Hardware UART interfaces (UART0, UART1, UART2)
  • SPI: 3x SPI interfaces (SPI, HSPI, VSPI)
  • I2C: 2x I2C interfaces (supporting master/slave modes)
  • I2S / SDIO / CAN: 2x I2S interfaces, SDIO Host/Slave, CAN Bus 2.0B controller (TWAI)
• Onboard Controls & Indicators:
  • Buttons: EN (Reset) Button and BOOT (GPIO0 Flash / Download) Button
  • LED Indicators: Power LED (Red) and User / Test LED (Blue - connected to GPIO2)
• Antenna: Onboard PCB trace antenna (3D impedance matched)
• Operating Ambient Temperature: -40°C to +85°C
• Dimensions: Approx. 55 mm × 28 mm × 12 mm (L × W × H, including pin headers)

Features

• True Breadboard-Friendly Narrow Width: Engineered specifically with a compact row spacing that fits directly into standard 830-point / 400-point breadboards while leaving accessible pin columns on both sides for jumper wire hookups.
• Dual-Core 240MHz Computing Power: Dual 32-bit cores allow dedicated real-time Wi-Fi/Bluetooth stack management on one core while executing sensor parsing, algorithms, or FreeRTOS tasks on the other.
• Comprehensive Dual Wireless Radio: Combines high-bandwidth 2.4GHz Wi-Fi for cloud connectivity (MQTT, HTTP, WebSockets) and low-power BLE for smartphone pairing, beaconing, and local provisioning.
• Plug-and-Play USB Programming: Built-in CP2102 USB-to-UART converter with auto-download reset circuitry eliminates manual button pressing during Arduino IDE, ESP-IDF, or MicroPython sketch uploads.
• Rich Peripheral Set: Integrated 12-bit ADCs, dual 8-bit DACs, hardware PWM, touch sensors, and hardware crypto acceleration (AES, SHA-2, RSA, ECC).

Common Applications

• Smart Home & Building Automation: Wi-Fi smart switches, smart plugs, climate controllers, and Home Assistant / ESPHome nodes.
• Industrial IoT & Telemetry: Remote sensor datalogging, Modbus RTU-to-Wi-Fi bridges, and cloud-connected MQTT gateways.
• DIY Robotics & Motor Control: Bluetooth/Wi-Fi controlled rovers, drone flight controllers, and multi-channel servo robotic arms.
• Environmental & Weather Monitoring: Solar-powered weather stations with deep-sleep power saving and cloud dashboard integration.
• Audio & Voice Streaming: Web radio streaming, I2S DAC audio playback, and Bluetooth audio sink applications.

Usage Tips

• 3.3V Logic Level Safety: All GPIO pins operate at **3.3V DC logic levels and are NOT 5V tolerant**. When interfacing with 5V sensors or 5V microcontrollers (e.g., standard 5V Arduino boards), always use a bidirectional logic level shifter or resistor voltage divider.
• ADC2 Wi-Fi Conflict: ADC2 channels (GPIO0, 2, 4, 12, 13, 14, 15, 25, 26, 27) cannot be used for analog reading when Wi-Fi is actively transmitting. Always prioritize **ADC1 pins (GPIO32 to GPIO39)** for analog sensors when Wi-Fi functions are active.
• Input-Only Pins (GPI): GPIO34, GPIO35, GPIO36 (VP), and GPIO39 (VN) are **input-only pins**. They do not possess internal pull-up/pull-down resistors and cannot be configured as digital outputs.
• Power Supply Peak Current: During Wi-Fi calibration and transmission bursts, the ESP32 can draw transient current spikes up to 500mA. Use a stable 5V power supply rated for **at least 1.0A to 2.0A** to prevent brownout detector resets.
• Boot Strapping Pins: Avoid pulling GPIO0, GPIO2, GPIO12, or GPIO15 HIGH or LOW externally during startup, as they determine chip boot modes (flashing vs. SPI boot).

Datasheet