Georgetown-based technology start-up SmartThings, which helps customers control items in their homes through their smartphones, raised $12.5 million in early stage funding from Silicon Valley venture firms Greylock Partners and Highland Capital Partners.

The company has raised $15.5 million in total since its founding in 2012, as well as $1.2 million on Kickstarter, a Web site on which large groups of small donors fund projects.

SmartThings sells kits containing sensors that connect wirelessly to smartphones, allowing people to control and monitor their homes remotely. Users can be notified if a door opens at home or if there’s water damage while they’re out, for instance. This network of interconnected devices has been dubbed by some as the “Internet of Things”.

SmartThings will use its most recent round of financing to improve its products and distribution, according to the company.

Greylock partner Josh Elman and Highland partner Manish Patel will also join SmartThings’ board of directors.

“SmartThings is taking a unique approach to a new era in human-machine interaction that merges the physical and digital worlds,” Patel said in a statement. “The power of the Internet of Things lies in having as many connection points across as many verticals as possible.”

SmartThings has about 40 employees, divided between offices in Washington and Minneapolis.