AZDelivery 5 x Capacitive Hygrometer Soil Moisture Detection Sensor Module V1.2 for Arduino and Raspberry Pi including eBook

I can't say about how these work in just moisture, but I used them in pure water (so really high moisture) and it worked perfectly for about 16 days, before the probe actually fell apart. I noticed it within minutes of use, and over 2+ weeks the effect of electrolysis happened and one side of the probe literally turned to nothing. Going to try a replacement probe using just nails later down the line, but up until that point it worked well. Like I said, I had it in water directly, but this will really just be a faster process than what can be expected it only moist soil samples.Using a esp8166, I could monitor the water level in my christmas tree on my phone, with notifications when it ran below a set point.

These are really nice kits for the money and should prove very reliable if used properly. I say this because I see from the comment left by other purchases that doubts have been raised about the longevity of the sensors. This seems to stem from misuse in my opinion as people have been connecting these up to a permanent DC voltage to get a continuous reading from the analogue output pin while leaving the sensor submerged in water. When you do this you have created an electrolysis plant, so it is little wonder the metal is removed from one electrode and plated onto the other. The nature of a soil moisture sensor is that you take periodic readings throughout the day, hourly for instance. This only needs the sensor to be powered up for a ms or so once an hour when the reading in made by a connected micro-controller. Used this way electrolysis never get the opportunity to get going so the sensor stays good. Hope this was helpful to some.

The plating on this sensor is very poor and thin, running only at 3.3 volts with the included amplifier PCBA, the plating completely failed on one electrodes within 2 days in tap water. No surprise really as Electrolysis is taking place. The plating should be much better quality and thicker, Hard gold would be ideal, but just plating with a decent thickness of bright tin would have been ok.Also I had to use the Analogue pin on the PCB, even though the voltage changed between 3.3 to 1.5 volts between the 2 states I wanted to detect, adjusting the pot could not get a clean 1 or 0, poor circuit design on PCBA.

The modules are great, but if you leave them on all the time, the tracks on the sensor boards will be eroded away by electrolysis in a couple of weeks. Just turn them on, take a measurement, and turn them off again. I flagged this the the manufacturers and they sent me a new set, so I can't complain. Don't be put off. These are great sensors. Adjust your design to turn them on when you need to take a measurement, turn them off again.