At 03:58 PM 5/23/2007, alan smith wrote: > > Presently the sensing is done using a load sensor that sits > underneath a fake stone so stepping on it causes an analog voltage > to change and thus triggers. I've been there once under contract > to repair, where the load sensor took a voltage spike and had to > replace (about 1K ea) I'm quite curious about the failure mechanism. Load cells are usually extremely robust devices so long as the strain gauge elements are protected from physical damage. Quite frankly, my first thought would be to use load cells if I were asked to design a similar system. I've simply not had unexplained failures in all my previous experience with them. My suggestion would be to visit the site and see just what problems currently exist. dwayne PS - please mention what problems you find. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist