It's another of those cool things from Google I/O that nobody is talking about enough -- Android Open Accessories. Still in its geek-stage of development, Open Accessories have the potential to change the way we use and interact with our smartphones and tablets. But what exactly are they?
Think of it as a new way to use the USB port. It's different from the USB host support we've seen hackers and modders build in the past, and Google itself supports in Android 3.1. Open Accessories are designed to be used on any Android device (2.3.4 or higher), because the accessory acts as the USB host. A developer will build some hardware (using something like the Microchip PIC24F you see on the left in the picture above -- they'll get smaller, that's a dev board) that can set up a handshake with any Android device. Once the handshake is complete, the correct app starts, or if it's not installed, it's market page opens so it can be. Très cool. After that, control is passed to the application that will use the accessory and everything is up to the great minds that develop Android applications.
We saw the demo using the excer-cycle at Google I/O, but that's just the tip of the iceberg. I can see all sorts of gadgetry being possible -- IR transmitters, portable medical diagnostic equipment, multi-meters, and so on. The tools are in place, both the reference hardware as well as the Open Accessory Development Kit (ADK), and the people I talked to at Google I/O seem pretty darn excited. Hopefully the idea takes off, any bugs and kinks get worked out, and we start to see some offerings using this new technology.
Source: Android Developers Blog