I've heard: 1) gyros 2) multi-axis accelerometers. 3) edge sensing (in the image) via DSP software. Some apparently work better than others. (3) was described in conjunction with a camera whose image stabilization was said NOT to work very well. BillW -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! use mailto:listserv@mitvma.mit.edu?body=SET%20PICList%20DIGEST