If the switches are SPDT (or you have a relatively small pull-up or pull-down when the switch is open), you could build an R-2R ADC using the switches. Harold > Think binary :) > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available! -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist