The USB Host Shield 2.0 is a powerful add-on module that enables Arduino boards to function as a USB host. Unlike a normal Arduino USB port, which only allows the board to connect to a computer, this shield allows your Arduino UNO, Mega, or ADK board to directly control and communicate with external USB devices.
Based on the MAX3421E USB host controller, the shield supports a wide range of USB peripherals including keyboards, mice, gamepads, barcode scanners, USB flash drives, Bluetooth adapters, and Android devices through Android Open Accessory (ADK) mode.