The device has an ESP32-S2 module that allows it to be identified as a keyboard + USB disk. It also a microSD slot that can be identified as MSC SD Card.

The new ESP32-S2 module from Espressif addresses the security flaws in the original ESP32. While the ESP32-S2 does include improved security features, it lacks the Bluetooth capabilities of the original ESP32 module. But it supports native USB.

WUDopen in new window


  • ESP32-S2 Module
    • Xtensa® Single-Core 32-bit LX7 Microprocessor (up to 240MHz)
      • RISC-V ULP Coprocessor
      • 128KB ROM and 320KB SRAM
      • 4MB of Embedded SPI Flash Storage
    • Cryptographic Hardware Accelerators
      • AES, ECB/CBC/OFB/CFB/CTR, GCM, SHA, RSA, and ECC (Digital Signature)
    • Physical Security Features
      • Transparent external flash and RAM encryption (AES-XTS)
      • Secure Boot feature ensures only signed firmware (with RSA-PSS signature) is booted
      • HMAC and Digital Signature modules use software inaccessible keys to generate SHA-MAC and MAC signatures
    • Integrated 802.11 b/g/n WiFi 2.4GHz Transceiver (up to 150Mbps)
    • Integrated Temperature Sensor (-20°C to 110°C)
    • Operating Voltage: 3.0 to 3.6V
      • WiFi: 310mA (peak)
      • Light-Sleep: 550µA
      • Deep-Sleep: 20-235µA
  • USB-A Connector
  • Micro SD slot
  • Hall sensor for control GPIO 0 of ESP32

Hardware overview

  • Board Dimensions
    • 17mm x 50mm (Without USB case)
    • 19mm x 62mm (With USB case)
  • USB-A Connector
  • Micro SD slot
  • ESP32-S2 mini Module
  • Buttons
    • Reset button
    • Hall sensor for control GPIO 0 of ESP32
  • Status LED - This indicator is connected to GPIO 21

Device Firmware Upgrade through USB

The ESP32-S2 chip needs to be in bootloader mode for the detection as a DFU device and flashing. This can be achieved by pulling GPIO0 down, pulsing RESET down for a moment and releasing GPIO0.

How to make the ESP32-S2 go to bootloader mode

  1. Plug the WUD to laptop
  2. Make a magnet close to the hall sensor (GPIO 0)
  3. Press the reset button, WUD will go to bootloader mode now

Software overview

The pre-flashed firmware is "wireless USB diskopen in new window". It use ESP32-S2 as an USB Disk with Wireless accessibility. HTTP file server be used with both upload and download capability.

Note: It's a demo code. Don't use it in serious application.



Contributors: yanc