USB Soil Moisture, Temperature Sensor

26.62 Price including 21% VAT

In stock

SKU: PM-WCS-3-USB Category:



  • Android and Raspberry Pi client demo software.
  • Dust and water proof
  • Low cost and easy to use.
  • Fairly accurate readings
  • Calibration functions for EC and Dielectric permittivity
  • USB CDC-ACM virtual COM port and 115200 baudrate


    Min. Typical Max.
    Supply voltage (VCC), V 2.5 5 6
    Working current(VCC=5V), mA 11 14
    Operating Temperature Range, Celsius -20 60


    Table 2.2.1

    ID Parameter Resolution /avg Tolerance Range
    1 Dielectric permittivity (ε)

    (Temperature corrected)

    0.1ε /5% 1 (air) to 80 (water) 
    2 Electrical Conductivity


    0.01 mS/m /20% 0…300 mS/m
    3 Temperature (°C) 0.1°C /3% -20 to 60°C 
    4 Volumetric Water Content (%) calculated from dielectric permittivity by Topp equation (Topp et al, 1980):

    θ = 4.3 ⋅ 10−6ε3 − 0.00055ε2 + 0.0292ε − 0.053

    1%  0 – 100% VWC 



    Sensor dimensions 114 x 24 x11

    Cable length 2.4m


    Sensor model PM-WCS-3-USB supports USB CDC-ACM virtual com port with 115200 baudrate.

    Sensor is equipped with standard USB 2.0 cable.

    On linux it will be detected as /dev/ttyACMx .

    For linux permissions settings please consult:

    On Linux you may use minicom utility to configure sensor.

    For windows PuTTY may be used.

    We recommend Android mobile application for sensor setup and data reading/storage described in chapter 5.1.

    3.2.1 USB interface sensor data format

    PM-WCS-3-USB data output prints comma separated values (CSV) sequenced as described in  Table 2.2.1 (Chapter 2 MEASUREMENT PROPERTIES). Optionally you may setup EPOCH time (Table 3.2.1 command: “time”) in seconds and there will be time parameter added in front.

    Table 3.2.1 USB device interface commands

    Command Response Explanation
    read sesnor data request response sensor data reading
    millis <period> sesnor data sensor will start report data  repeated by setup period in milliseconds, this option may be used to redirect data to log file.
    time <Epoch> OK setup current Epoch time in seconds – need to setup after any power loss of the sensor.
    int <int. sec.> OK set USB odffline memory write interval in seconds
    mem <data> get offline data accumulated (max 320dp)
    ver <version> print device type and version number
    info <info> infoUSB,millis,off-Interval,appId, devId
    appid <appId> OK set appId
    devid <devId> OK set devId

    3.2.2 Redirecting sensor reading data to file on Linux systems

    You can write simple script to start log sensor USB data to CSV file.

    This sample is written for Raspberry Pi, Debian, Ubuntu linux, before executing script you have to install minicom: sudo apt-get install minicom



    #sensor serial port name


    sudo stty -F $PT speed 115200 cs8 -cstopb -parenb -echo raw

    #setup current time

    echo -ne “time $(date +%s)\r” > $PT

    #set time period 5 seconds in milliseconds and start logging

    echo -ne “millis 5000\r” > $PT

    #flush some output

    timeout 2s cat $PT

    #print output to file

    cat $PT > swout.csv 2>&1 &



    Sensors are already factory calibrated, but in case needed they may be recalibrated using USB terminal interface as described for device specific commands.


    Table 3.2.1 USB device interface commands

    Command Response Explanation
    water OK Put sesnor in to water and issue this command
    air OK Hold sesnor in air and issue this command
    ec <uS/m> OK EC calibration, set right sensor reading value in uS/m

    We recommend Android mobile application for sensor setup and data reading/storage described in chapter  5.1.


    1. remove battery, attach to phone
    2. open application & wait for  USB connected status or connect
    3. go to SETTINGS tab,
    4. hold sensor in the air – click button AIR
    5. submerge sensor in the water or soil with water, click button WATER
    6. go to MAIN tab click read to test calibrated values

    Get it on Google Play

Additional information

Weight 0.3 kg
Dimensions 14 × 5 × 5 cm