Spending on the Internet of Things ultimately will have a ceiling, but presently it's hard to see where that would be. Overall IoT tech spending is now at $140 billion and will grow 18% a year to $322 billion within five years, according to a new study by Zinnov Consulting.

While plenty of challenges surround the Internet of Things, there's one that tops the list, even over security. The most immediate challenge is quantifying the return on investment or defining a clear use, based on a new study. There are plenty of other challenges, according to a survey of 360 IoT professional.

A Wisconsin company had its planned 'chip party' Tuesday and 41 employees had microchips implanted into them. Those employees, all who volunteered to have an RFID (radio frequency identification) chip implanted between their thumb and forefinger, now can use their hand to unlock doors, log on to computers and pay at kiosks or terminals that take credit cards. I caught up with Tony Danna, vice president of international sales at Three Market Square, just after the chip party at the company's River Falls headquarters.

There's security relating to the Internet of Things and then there's the other side of security, relating to someone's physical home. While some consumers are moving to smart devices inside their houses, they also are migrating to connected technology that enables someone to get in - or not get in - to that same house. Despite the relatively high cost, 2 million smart door locks will be sold by 2021, according to a new study by Parks Associates.