When guests check into the hotel, they can download the free Personality Hotels app onto their smartphone. Once the front desk assigns a room, it alerts the app. When they reach the door to their room, all guests have to do is press the key icon to emit a sound that activates the door sensor and unlocks the door.
"I think our guests are embracing that because they're right here where all the high technology and new technology is happening," Yvonne Detert, the president and CEO of Personality Hotels, told CNET's Kara Tsuboi.
As a security measure in case their phone is lost or stolen, guests can create a special PIN for the app -- in addition to the PIN on their phone. Detert explained that the app doesn't reveal which hotel the guest is staying at or their room number, so a thief shouldn't be able to use it.
Personality Hotels isn't the only group to experiment with mobile electronic keys. Some properties in the Starwood Hotel group, like Aloft, are expected to roll out their version of the technology in the coming months.
"In five years from now, it may just be your thumbprint. It may be the glasses you're wearing that have the computer set into it. Just blink at the lock and you're in," Detert said.
Currently, 25-30 percent of Personality Hotel guests are taking advantage of this high-tech system. For guests who want to try it but don't own a smartphone, a special melody code can be texted to a regular cellphone -- like a flip phone -- to gain entry into their room.
For guests who still prefer the old-fashioned way, plastic key cards are still available.