09-08-2016, 09:26 AM
It isn't a problem related to the number of readings per second... If I plug the scale to the original display, the current draw remains the same (>1mA).
It seems that the arduino input port has low input impedance and overloads the output-stage of the scale (permanently damaging the scale).
I've tried to put an opamp (unity gain stable, single supply, rail-to-rail) and it works, the (new) scale draws only 15uA (the old scales continue to draw a lot of mA).
It seems that the arduino input port has low input impedance and overloads the output-stage of the scale (permanently damaging the scale).
I've tried to put an opamp (unity gain stable, single supply, rail-to-rail) and it works, the (new) scale draws only 15uA (the old scales continue to draw a lot of mA).