The SmartQuill was a working prototype pen computer. My goal were to encapsulate an entire handheld computer in a pen. It allowed capture of handwriting and a special gravity controlled screen allowed the user to view documents by moving the computer in the hand. I also wanted to replace the mouse with motion sensing. I invented it in April 1997 in Leighton Buzzard, Bedfordshire I exchanged emails with BT re my invention and in June 1997- Oct 98 worked for BT Labs, Martlesham, UK, Sensior Research Fellow, to build a working prototype.
The SmartQuill had an accelerometer or tilt sensor , an Analog Devices ADXL202 , the function was to allow the user to tilt the pen and scroll through the pages. The images could be inverted and changed from portrait to landscape.
The pen could achieve up to 96% handwriting recognition accuracy as here ( software by B Milner)
I then left BT and was asked to work for Microsoft in 1998.