At Microsoft’s Build developer conference in San Francisco the company is showing off new features of Windows 8.1, now in preview, a major update to Windows 8.0.

In a session on the Windows Runtime, the platform behind the tablet platform in Windows 8, there was a dramatic moment when a huge black ball rumbled onto the stage and threatened to destroy the “Lemonade stand” which the presenters were using to showcase how a very small business might use Windows 8.

The significance of the ball (a custom Sphero) is that Windows 8.1 has Bluetooth APIs built in, so that app developers can easily control a Bluetooth device from code.

Robotics is an obvious application, but with increasing numbers of Bluetooth devices out there, this is a smart move by Microsoft.