Скачать или смотреть Saliferous - a Creative Electronics project - team 10

How our project works:

In the circuit we used a voltage divider consisting of a 100k resistor and the water (We measured the resistance of water and found values in the same order of magnitude. We chose this resistor as to make the voltage divider work effectively). We measure the output of the voltage divider by connecting it to an analog pin and using the command Serial.println(). Based on our measurements, we changed the color of the RGB LED. We connected the R-pin and the G-pin to two digital pins (one for each pin) and used the command digitalWrite( … , HIGH / LOW) to turn on the right pins. When the pins are not in water, we measured a value at least twice as high as the measured results. We used this value to turn off the lamp: the device would not be on if the wires are not in water.

Important notes:

Instead of connecting the voltage divider directly to the source, we connected it to a digital pin. A redox-reaction between our sensor and the water was interfering with our measurements, so using the digital pin we limited the amount of current that would go through the water and therefore the effect of the redox-reaction. Also: the distance between the pins influenced our measurements, which is why we built our sensor in such a way that this variable would be constant. We cut the stripped part of the wires as short as possible so these would not be able to bent in between measurement and alter our results.

References:

Araujo, T. [Troy Araujo] (2016, July 30). ✔How to make a "Water Level Indicator" on Breadboard [HD]💡 [Video file].
Retrieved on March 27, 2018 from
   • ✔How to make a "Water Level Indicator" on ...  

Circuit globe. Earth Resistance [Blog post].
Retrieved on March 27, 2018 from
https://circuitglobe.com/earth-resist...

Mert Arduino and Tech (2016). analogRead Serial Monitor with Potentiometer [Blog post].
Retrieved on March 28, 2018 from
http://mertarduinotutorial.blogspot.n...
Monk. S (2005-present). Arduino Lesson 3. RGB LEDs [Blog post].
Retrieved on March 28, 2018 from
https://learn.adafruit.com/adafruit-a...

Soeren. (2011, February 7). Re: Water Resistance: Tap Water vs. Salt Water [Blog comment].
Retrieved on March 28, 2018 from
http://www.societyofrobots.com/robotf...