If you are wondering about what the dude in the picture above is doing, well he is trying out a USB accessory called CardioQuest which is used to monitor his heartbeat while pedaling/exercising.
This new gig will allow developers and inventors to make accessories which will work with a specific software either already installed in the Android devices or will need to be downloaded before use. This service will be free and doesn’t require developers to go through an approval process. Google will also offer support for the accessory design kit (ADK) for both the software and the hardware parts.
The Android Open Accessory is only supported through USB at the moment and Google promises a Bluetooth support for it in the near future. Your Android device will act like a PC when you plug in a USB accessory. You will either be prompted to download the accessory’s software or use a compatible application either already installed in your phone or available at the Android Market.
For more in-depth explanation about how this Android Open Accessory process will work, you can head directly to the Android developers page and check it out.