Nigel, Please, what is ETI? and how do I obtain this 'issue'? Matt > > The current issue of ETI (the one with the PIC programmer) has a PH meter > design, it uses a 16C84 and a MAX187 12bit ADC - AND it gives the source > code for the design. > /*****************************************/ /* Matt Calder, Dept. of Statistics, CSU */ /* http://www.stat.colostate.edu/~calder */ /*****************************************/