# USB Host Expansion Board, MAX3421E

> USB Host Expansion Board (Shield) based on MAX3421E, adds USB Host functionality to Arduino UNO and MEGA boards. USB 2.0 compatible, supports HID, Android ADK, SLR cameras, game console controllers, GPS, FTDI; Mass Storage FAT32 only on MEGA. Supply voltage 3.3-5V DC. Dimensions: 55 x 53.3 x 23.8mm.

- Page: https://sigmanortec.ro/en/usb-host-expansion-board-max3421e
- Price: 45.85 RON
- Availability: Out of stock
- Reference: 33367 · EAN: 5941316261691
- Category: Mechatronics and IoT > Shields and Expansion Boards
- Package (shipping data): 0.018 kg
- Updated: 2026-05-12
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 03:58 (Europe/Bucharest)

## Description

The expansion board that adds USB Host functionality for Arduino, based on the MAX3421E, providing control over peripherals such as a mouse, keyboard, or controllers. It supports Google Android ADK and compatible libraries, works with UNO and MEGA boards, is USB 2.0 compatible, and accepts a wide range of HID, GPS, FTDI, and other devices, power supply 3.3-5V.
The USB Host expansion board (Shield) is a compact and versatile solution designed to add USB Host support to Arduino-compatible development boards, including UNO and MEGA. Based on the MAX3421E integrated circuit, this board turns the base board into a Host device capable of managing and controlling a wide range of USB peripherals.
In the USB architecture, the Host device has control over communication with connected peripherals. It is important to note that two peripherals, for example two keyboards, cannot communicate directly with each other, only through a Host.
The board is compatible with the USB 2.0 standard and offers native support for a wide variety of devices: HID (mouse, keyboard), Android ADK, SLR cameras, game console controllers, GPS devices, FTDI adapters and others. It also supports Mass Storage devices with FAT32 file system, however this functionality is available exclusively for the Arduino MEGA board.
Compatibility with Google Android ADK allows direct interaction with Android devices, including ADK packages and DK-compatible source files compiled for Arduino.
The board operates at supply voltages between 3.3V and 5V DC, making it suitable for use together with Arduino UNO, MEGA, as well as other platforms compatible with 3.3V or 5V logic levels, such as certain STM32 or ESP32 variants with a level shifter.
Specifications:
Supply voltage: 3.3 - 5V DC
USB compatibility: 2.0
Main chip: MAX3421E
Supported devices: HID, Android ADK, SLR cameras, game console controllers, GPS, FTDI
Mass Storage: FAT32 (Arduino MEGA only)
Compatible with: Arduino UNO, Arduino MEGA, 3.3V/5V logic level platforms
Dimensions mm: 55 x 53.3 x 23.8mm
Instructions:
To operate, the board must be powered by creating a connection between the circled 5V and 3.3V pads in the image below.
USB PWR represents the voltage that physically reaches the USB port and only one jumper should be shorted.
Power Select requires soldering both jumpers (5V and 3.3V) because the 5V pad powers the USB port while the 3.3V pad powers the MAX3421E integrated circuit.
Mount the shield on the Arduino UNO or MEGA board, aligning the pins correctly across all connector rows.
Solder both pads in the Power Select area (3.3V and 5V) at the same time. This is the standard configuration for Arduino UNO, Duemilanove, Mega and Mega 2560. The 5V pad powers the USB Host port (VBUS) to the connected device, while the 3.3V pad allows the onboard regulator to supply the voltage required by the internal core of the MAX3421E. The two pads do not directly short the two voltages; conversion is handled in a controlled way by the regulator on the shield.
Solder only the 5V pad in the VBUS PWR area to provide proper power to the USB Host port. The USB standard requires 5V on the VBUS line regardless of the platform used.
Download and install the USB Host Shield Library 2.0 from the Arduino Library Manager or from GitHub (felis/USB_Host_Shield_2.0).
Open Arduino IDE and select the appropriate example for the desired device from the HID folder (e.g. KeyboardController for keyboard or MouseController for mouse).
Connect the Arduino board to the computer using the USB cable.
Select the correct board and port from the Tools menu in Arduino IDE.
Upload the sketch to the board using the Upload button.
Connect the USB device (mouse, keyboard, etc.) to the shield’s Type A USB port.
Open Serial Monitor at 115200 baud to verify the data received from the connected device.