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#197883
Hello,

I want to know if the SparkFun SEN - 13322 soil moisture sensor has a specification or data sheet that lists power consumption, operational temperature, accuracy, resolution, and life span? For example: power consumption <13 mA, operational temperature -40 to 50 C, accuracy 3% volumetric water content (VWC), resolution 0.1 % VWC, life span 3 to 5 years (this relates to the sensor being in the wet soil). I search through google and could not find majority of these details not even in the "Soil Moisture Sensor Hookup Guide" that learn.sparkfun.com provided. All I could get from the guide was the voltage to power the sensor, which was 3.3 - 5V. I plan to do an experiment which calibrates the sensor to the soil it will be used in to find most of these details, but I thought I ask the manufacturer (or SparkFun) first to eliminate some of these details. Thank you for time and I look forward to your responses.
#198276
Whatever current it consumes (depends on the conductance of the soil/whatever sludge solution) it has to go through a 10k resistor. So with a 5 volt supply and atleast that amount of resistance (transistor fully conducting) the current is at most 5/10,000.= 0.5 mA

Accuracy or resolution makes no sense. As this device converts soil resistance to voltage through a transistor/resistor voltage divider. You need to calibrate it yourself. A known moisture content gives this reading. Another moisture gives that reading. It's a pretty dumb thing. You've got to do the calculations from the datapoints yourself. The microcontroller ADC or multimeter determines the resolution. It's not part of the product.