This interesting article from the New Scientist website describes intriguing new research which allows a pencil sketch to be used as a sensor.
Yue Zhang from the University of Science and Technology Beijing have developed a sensor which measures how much a piece of paper is bent using a rectangle drawn with an ordinary graphite pencil.
The eventual aim is that the simple, cheap device could be used for wearable technology, and the researchers have already demonstrated that it can monitor the movement of limbs and determining pressure.
The device is very inexpensive and can be reused many times, and could be made into alarms that go off when a book or door is opened.
Such technology is certainly interesting, and the Zhang and co-workers are currently looking into what companies might be interested in taking this further. Cool stuff!