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  1. JLB1

    Question on the Plants Watering Watcher circuit

    Audioguru, Thanks again. If you mixed a level teaspoon of salt ( about 5 grams) in 19 oz ( 454 grams ) of water you had some 11,000 ppm solution. Your probe is simmilar to the one I use, so your info is very interesting. I will see if I can overcome the alinearity .......... or live with it...
  2. JLB1

    Question on the Plants Watering Watcher circuit

    Sorry, I meant to type CD74HC132. By the way, do you think that wit the suggested modifications the circuit will show a linear response respect to the media conductivity? I plan to measure the conductivity of salts dissolved in water from 0 parts per million to 3000 parts per million. This is...
  3. JLB1

    Question on the Plants Watering Watcher circuit

    Hi there Audioguru: I was a little bit shocked by the level of controversy that my simple question started. As a matter of fact I started to look into other circuits as this one ( as it was) had some additional problems like the 10% mark to space ratio that polarized the probe, and the fact...
  4. JLB1

    Question on the Plants Watering Watcher circuit

    I have built the Plant Watering Watcher circuit presented under Projects, "science related" circuits and works to a certain extent. Problem is that I find that the LED has only two states ( ON or OFF ), it does not dims gradually as the description states. As a matter of fact I think that the...
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