This review is written by one of our customers T. Nielsen on Amazon.
About The Product:
Gravity:Analog Capacitive Soil Moisture Sensor- Corrosion Resistant measures soil moisture levels by capacitive sensing, rather than resistive sensing like other types of moisture sensor. It is made of a corrosion resistant material giving it a long service life. Insert it into soil and impress your friends with the real-time soil moisture data!
This capacitive soil moisture sensor does not corrode like the cheapy little non-capacitive/standard soil sensors you see around (those usually corrode within a month or so, sometimes less). This analog sensor from DFRobot is supposed to last years without going bad! This operates at nearly the same voltage (3.3 ~ 5.5 VDC) and works without additional resistors needed. The moisture range differs from standard sensors. Dry is 520-430, moist is 430-350, and wet is 350-260.
On this moisture sensor, you will see a white line near the component side - this is your moisture/water warning level, meaning you do not want moisture above that as it can damage the components. I am using this in a planter that will be watered on and off as needed and didn't want to worry about components getting wet, so I put it in a project box (uxcell Waterproof Plastic Electric Project Case Junction Box (2.3x1.4-Inches, 5pcs) that I then cut a hole into on the side with a dremel tool about the width of the sensor. I also cut a smaller hole on top for the sensor wires. I slide it in and added some foam padding to keep it in place. Lastly, I used acid-free silicone (GC Electronic Grade Silicone Sealant / Adhesive (3oz.) : 19-155) to waterproof the ends.
Attached are some pictures to help give you an idea of my process water proofing it. I didn't take one with silicone on it yet, but that is a crucial step!
I love this thing. I'm so happy with it and excited to be using it in my smart greenhouse project. I will keep this review updated in case it fails early or I run into trouble, but I certainly feel MUCH better about using a capacitive moisture sensor from DFRobot than the cheapy standard ones that corrode after a short time... who wants to keep replacing those? Not me.
I highly recommend you do a search on the web for "dfrobot capacitive soil moisture sensor wiki" as they have a lot of great info on this device, including example code and recommendations, best practices, etc. I hope this review was helpful and will save people some time!