USB Host Shield for Arduino ARS3421U Arduino Shield Arduino Compatible in elecrow store.

USB Host Shield is an inexpensive development board designed to be used in embedded applications which require USB Host functionality. The board supports USB 2.0 full/low speed operation. Primary target platform is Arduino, however, it can also be used with any other micro equipped with SPI interface. This board’s layout is now compatible with much more Arduino compatible boards - not only UNO and Duemilanove, but also big Mega and Mega 2560 work with Standard variant of this shield out of the box. Of course it is compatible with Crowduino, too. With this board, let your Arduino communicate with other USB devices, and supports USB hub function.

External Link & Download

Arduino library and examples
Eagle Files
Manual
Demo Projects
Arduino USB Host Library Introduction
Wiki link