Microsoft gadget lets you spy on your own life.

SenseCam, touted as a visual diary of sorts by Microsoft Corp., is designed to be worn around the neck. The prototype responds to changes such as bright lights and sudden movements and can take up to 2,000 images in a 12-hour day without the wearer doing a thing.

One day, SenseCam might even respond to other stimuli such as heart rate or skin temperature — to track medical problems as easily as to record a Hawaiian vacation. And it could eventually link with other technology, such as face recognition to remind wearers when they’ve seen someone before.