I construct hand-made device to work with some biological sensor. That sensor got 600-800 mV of voltage and change current on line. How can I measure that current? Main problem in very low parameters - in normal tine current lays in 10-1000 nA (nano Amperes). I have working prototype (on base of Arduino Uno, MCP4725 and INA222), what simultaneously measure current and control voltage, but so tiny current INA222 cant see.
What do you advise?