[rodion]

There is a protocol called CoAP that has some traction [1,2]. It describes a standard for accessing sensor data and also includes discovery. Technically, I don't think there is a major challenge.

The problem, IMHO, is rather in who will pay for the physical devices. The common view is that there is no money to be made from the sensor hardware itself. Thus, the only way to sell hardware would be to bundle it with a service that the user pays for. Assume that I, as a utility company, subsidize a smart meter to be installed in customers' homes -- what would be my incentive to open it up to other developers?

[1] https://tools.ietf.org/html/rfc7252 [2] http://en.wikipedia.org/wiki/Constrained_Application_Protoco...