Give me idea for convert physic value to constance value

[wayu_ix]

hi everybody.
i can't sure i post true web board?
i want convert physic value (voltage curruent or '....) to a constance for send to variable in program computer.\
how to start idea and i can serch data form where?
thank you.

 

[Kurenai_ryu]

transducer + ADC

search all you want. this is the way...