Thanks to Sharp, you can leave your car keys at home. The consumer electronics manufacturer and NTT DoCoMo are taking the concept of Nissan’s Intelligent Keys a step further by letting the mobile phone automatically unlock owners’ car doors and start their engines without using an ignition key.

Sharp has integrated electronic intelligent key and wireless technologies into its new handset. When the phone is nearby, it automatically unlocks the car door. Once the phone is brought inside the vehicle, it will start the car.

Nissan, NTT DoCoMo and Sharp plans to demonstrate the new device at CEATEC Japan 2008 next week.

NTT DoCoMo said it expects to offer the handsets and service in Q1 2009.