Arduino soil moisture sensor

This is sensor for arduino to measure moister in soil. Its the same copy of small sensor you can buy, but this sensor can measure deeper in soil. All depend how long is exposed (how long is insulated part). Normal sensor read top moister of soil but in greenhouse or garden you must go deeper to get better result of reading. This sensor start reading moister from 5 to 10cm deep. Transistor is NPN 2N2222A Switch is sensor probe Voltmeter is analog reading. You can use +3,3V or +5V. For probe use galvanized wire 2x 15cm long. First 5cm is in protected cover wth circuit, other 5cm is insulated and last 5cm is exposed wire. Space between wires is 3cm. To change analog read to humidity value look Read Analog Voltage for code. You must know that soil moister depends all how much metal (electrical conductive material) are inside. For a sample if you have dry soil you can get some measurements and diffrent soils have diffrent results. The second thing is water and depends the same like soil metal. If you use rain you get less conductivity then water with alot of metal inside. For best results i recomended that you make some test with water conductivity and then use dry soil and add some water and test how moister change.

published 9 years ago