One of the biggest announcements of Google's IO conference has been the launch of a kit for creating accessory hardware for Android-based devices - and it's proven one of the company's most popular moves yet.
The kit, unveiled at the conference yesterday, takes the form of an Arduino Mega2560-based prototyping board and shield - giving coders the ability to create real-world USB-connected accessories for their Android-based smartphones and tablets.
The 'demo' shield, which attaches to the top of the board, implements a joystick, RGB LED outputs, temperature, and light sensors - giving developers who haven't worked with the Arduino platform before a taste of just what they can create using the development kit.
Launched under the name Android Open Accessory Development Kit, it's an official royalty-free route for companies and hobbyists to create Android-compatible devices - and it's already proving popular.
The company behind the hardware, Japan-based RT Corporation, has sold out of its initial production run of the kit and shield in a single day - helped along by an impressive demonstration of a humanoid robot powered by a combination of an Android smartphone and a USB-connected development kit.
With another production run expected at the end of May, RT Corporation looks to have a hot product on its hands - and Google has gained another string in its bow as it fights to against Apple's rival iOS platform for developers' hearts and minds.
There are possible speedbumps on the way, however - starting with compatibility. Currently, the Open Accessory Development Kit only supports Android 3.1 and Android 2.3.4 - with users of earlier devices unable to communicate with the hardware.
Worse, Google admits that future support may not be universal across all Android devices. "Accessory mode is ultimately dependent on the device's hardware," the company has warned developers, "and not all devices will support accessory mode." For a developer wanting to create a 'universal' accessory that can be put into mass production as a commercial venture, that's bad news.
For hackers and tinkerers, however, the launch of the Open Accessory project is great news - and one which Google is using to reaffirm its commitment to open source, with no royalty payments or commercial licensing required for developers to start playing with the kit.