Linear variable reflector sensors can be used to measure the displacement of objects. These sensors are useful in that they can be very small, do not conduct electricity, and are resistant to electrical interference from EMI/EMP and lightning strikes. The present linear variable reflector system comprises...http://www.google.com.au/patents/US7355726?utm_source=gb-gplus-sharePatent US7355726 - Linear variable reflector sensor and signal processor
