This is essentially a micro scale version of eg mechanical automatic watches which have been around for many decades. Different "vibration" source- essentially same principle. Could be useful but that's an extremely low power level (40 uW). > http://www.edn.com/article/CA6454543.html?industryid=47037&nid=2012 Vrussell. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist