Google's "Made for Android"

Google announces its Android Open Accessory standard-- an API allowing developers to build hardware that can interact with Android devices via USB port-- opening the gates to a possible future flood of accessories designed for Android devices.

ADKCurrently most Android devices are only able to act as USB devices, and can't initiate connection with external USB devices.

The API is compatible with both Android 3.1 and Android 2.3.4.

Google also has an Arduino-based reference hardware design, the Accessory Development Kit (ADK), available for developers to see exactly how to implement the standard.

So far it only supports USB, but Google promises Bluetooth support is in the works.

Go Android Open Accessory Development Kit