Homebrew PCBs

Stefan Trethan wrote:
> 
> A PH sensor might work, but i find the whole automatic control would be a  
> major effort,
> and would far outweigh the effort of manual care in about all situations i  
> can imagine.

pH will not give reliable acid molarity simply because HCl is a strong 
acid and pH will be very low for a very wide range of acid 
concentrations. Even if pH would give you measurement, pH electrodes are 
a LOT more expensive and cumbersome to use than simple eye dropper and 
NaOH.