What Google can really do with Nest, or really, Nest’s data
Open source smart thermostats rise to compete with Nest after Google acquisition | Ars Technica:
"open source version of a smart thermostat using their own Spark Core, an Arduino-compatible Wi-Fi development board. They added in a humidity and temperature sensor, IR motion detector, and some LEDs and LED matrices to put together and mount inside a custom wood and acrylic enclosure."
In all, the team completed its open source version in less than 20 hours for “about $70,” including their $39 Spark Core. The thermostat is still in the experimental stage and lacks much of the sophistication and “smartness" of the Nest, but it still constitutes a networked and remotely controllable thermostat that has a memory of its own work.