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Topic: Water TDS Measurement (Read 3929 times) previous topic - next topic

redneckengineer

thanks, i shouldn't have miss that.  It takes longer for the arduino to work thru that function now. i took the delay out of void loop().  the part i cant understand is how it doesnt seem to be charging the cap more than a 1 volt either way. i think i did the math right to figure out change times. that said it needs 1.5 microseconds to charge to like 87%. so 50 microseconds should be a huge overkill. i know i could put a large resistor in place of Rx but, i had a 5.6 M in there and still the same problem. i looked it up and water with TDS of 835 (in the range of TDS the final project would work in) only has the resistance of about 600 ohms. EC pin is set as a input at that point in the program so there shouldn't be any current bleeding thru the Rx resistor any ways, i dont know. 
thanks, red

smarti

Hey Red, know it's been a while but I'm trying to build a TDS as well and I'm just a beginner.
Did you manage to do it? Could you give me a hand?

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