The biometric sensor developer has now raised $13.5m in equity, after a series C round that included a second investment by electronics retailer Best Buy.

Valencell, a US-based developer of biometric sensor technology, has closed a $7m series C financing round that included investment from Best Buy Capital, the venture capital arm of consumer electronics retailer Best Buy.

Other investors in the round included venture capital firms True Ventures and TDF Ventures, and debt capital provider CBC Partners.

True Ventures and Best Buy previously invested in Velencell’s $5.5m series B round in June 2011. In November 2009 Velencell gained $1m from undisclosed backers.

“In the…