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Go Direct® Soil Moisture Sensor User Manual

Order Code: GDX-SM

Go Direct Soil Moisture is used to measure the volumetric water content of soil. This makes it ideal for performing experiments in courses such as soil science, agricultural science, environmental science, horticulture, botany, and biology. Use Go Direct Soil Moisture to

  • Measure the loss of moisture over time due to evaporation and plant uptake.
  • Evaluate optimum soil moisture contents for various species of plants.
  • Monitor soil moisture content to control irrigation in greenhouses.
  • Enhance your Bottle Biology™ experiments.

Note: Vernier products are designed for educational use. Our products are not designed nor are they recommended for any industrial, medical, or commercial process such as life support, patient diagnosis, control of a manufacturing process, or industrial testing of any kind.

What's Included

  • Go Direct Soil Moisture
  • Micro USB Cable

Compatible Software

Choose a platform below to see its compatibility requirements.

LabQuest
InterfaceLabQuest App
LabQuest 3Full support
LabQuest 2 (discontinued)Full support 1
LabQuest (discontinued)Incompatible

Compatibility Notes

  1. Wireless connection of this sensor to a LabQuest 2 requires a Go Direct Bluetooth Adapter when used with some older LabQuest 2 models.
Computers
Software
InterfaceGraphical Analysis
No interface requiredFull support 1
LabQuest 3Full support 2
LabQuest 2 (discontinued)Full support 2 3

Compatibility Notes

  1. For Bluetooth® connectivity, only computers running Windows 10 or Mac OS X 10.10 or newer are supported. The computer must also have a compatible Bluetooth 4.0+ radio.
  2. Connect this sensor directly to a computer or Chromebook via a USB or wireless Bluetooth® connection for best results. Alternatively, this sensor is fully supported when used with LabQuest 2 or LabQuest 3 when the LabQuest is connected to a computer or Chromebook via Wireless Data Sharing.
  3. Wireless connection of this sensor to a LabQuest 2 requires a Go Direct Bluetooth Adapter when used with some older LabQuest 2 models.
Chromebook
Software
InterfaceGraphical Analysis
No interface requiredFull support
LabQuest 3Full support 1
LabQuest 2 (discontinued)Full support 1 2

Compatibility Notes

  1. Connect this sensor directly to a computer or Chromebook via a USB or wireless Bluetooth® connection for best results. Alternatively, this sensor is fully supported when used with LabQuest 2 or LabQuest 3 when the LabQuest is connected to a computer or Chromebook via Wireless Data Sharing.
  2. Wireless connection of this sensor to a LabQuest 2 requires a Go Direct Bluetooth Adapter when used with some older LabQuest 2 models.
iOS
Software
InterfaceGraphical AnalysisGraphical Analysis GW
No interface requiredFull supportFull support
LabQuest 3Full support 1 2Full support 1 2
LabQuest 2 (discontinued)Full support 1 2 3Full support 1 2 3

Compatibility Notes

  1. Connect this sensor directly to a supported mobile device via a wireless Bluetooth® connection for best results.
  2. iOS and Android devices can only connect to LabQuest 2 or LabQuest 3 via Wireless Data Sharing.
  3. Wireless connection of this sensor to a LabQuest 2 requires a Go Direct Bluetooth Adapter when used with some older LabQuest 2 models.
Android
Software
InterfaceGraphical AnalysisGraphical Analysis GW
No interface requiredFull supportIncompatible
LabQuest 3Full support 1 2Full support 1
LabQuest 2 (discontinued)Full support 1 2 3Full support 1 3

Compatibility Notes

  1. iOS and Android devices can only connect to LabQuest 2 or LabQuest 3 via Wireless Data Sharing.
  2. Connect this sensor directly to a supported mobile device via a wireless Bluetooth® connection for best results.
  3. Wireless connection of this sensor to a LabQuest 2 requires a Go Direct Bluetooth Adapter when used with some older LabQuest 2 models.
Python
Software
InterfacePython
No interface requiredFull support
Javascript
Software
InterfaceJavascript
No interface requiredFull support 1

Compatibility Notes

  1. A wireless Bluetooth® connection can be made with Go Direct sensors on any platform running a browser with WebBluetooth support. However, only a few operating systems have been tested and testing has been limited.
LabVIEW
Software
InterfaceNI LabVIEW
No interface requiredFull support 1

Compatibility Notes

  1. For Bluetooth® connectivity, only computers running Windows 10 or Mac OS X 10.10 or newer are supported. The computer must also have a compatible Bluetooth 4.0+ radio.

Quick Start: Vernier Graphical Analysis® and Bluetooth®

  1. Charge your sensor for at least 2 hours before first use.
  2. Turn on your sensor. The LED will blink red.
  3. Launch Graphical Analysis, then click Sensor Data Collection.
  4. Select your sensor from the list. The sensor ID is located on the sensor label near the bar code. Note: If you don’t see a list of available sensors, click WIRELESS. After selecting your sensor, click Pair.
  5. Click DONE. You are now ready to collect data.

Using other Vernier data-collection apps or want to connect via USB?

Visit www.vernier.com/start-go-direct

Note: This sensor also works with LabQuest 2 and LabQuest 3; it does not work with the original LabQuest.

Charging the Sensor

Connect Go Direct Soil Moisture to the included USB Charging Cable and any USB device for two hours.

You can also charge up to eight Go Direct Soil Moisture Sensors using our Go Direct Charge Station, sold separately (order code: GDX-CRG). An LED on each Go Direct Soil Moisture indicates charging status.

Charging

Orange LED next to the battery icon is solid while the sensor is charging.

Fully charged

Green LED next to the battery icon is solid when the sensor is fully charged.

Powering the Sensor

Turning on the sensor

Press button once. Red LED indicator next to the Bluetooth icon flashes when the unit is on.

Putting the sensor in sleep mode

Press and hold button for more than three seconds to put into sleep mode. Red LED indicator next to Bluetooth icon stops flashing when sleeping.

Connecting the Sensor

See the following link for up-to-date connection information:

www.vernier.com/start/gdx-sm

Connecting via Bluetooth

Ready to connect Red LED next to the Bluetooth icon flashes when sensor is awake and ready to connect.
Connected Green LED next to the Bluetooth icon flashes when sensor is connected via Bluetooth.

Connecting via USB

Connected and charging Orange LED next to the battery icon is solid when the sensor is connected to Graphical Analysis via USB and the unit is charging. LED next to Bluetooth icon is off.
Connected, fully charged Green LED next to the battery icon is solid when the sensor is connected to Graphical Analysis via USB and fully charged. LED next to Bluetooth icon is off.
Charging via USB,
connected via Bluetooth
Orange LED next to the battery icon is solid when the sensor is charging. Green LED next to the Bluetooth icon flashes.

Identifying the Sensor

When two or more sensors are connected, the sensors can be identified by tapping or clicking Identify in Sensor Information.

Using the Product

Connect the sensor following the steps in the Quick Start section of the user manual.

Positioning the sensor

Figure 1 shows the proper placement of Go Direct Soil Moisture. The prongs should be oriented horizontally, but rotated onto their side, like a knife poised to cut food, so that water does not pool on the flat surface of the prongs.

Figure 1

The horizontal orientation of the sensor ensures the measurement is made at a particular soil depth. The entire sensor can be placed vertically, but because soil moisture often varies by depth, this is not usually the desired orientation. To position the sensor, use a thin implement such as a trenching shovel to make the pilot hole in the soil. Place the sensor into the hole, making sure the entire length of the sensor is covered. Press down on the soil along either side of the sensor with your fingers. Continue to compact the soil around the sensor by pressing down on the soil with your fingers until you have made at least five passes along the sensor. This step is important, as the soil adjacent to the sensor surface has the strongest influence on the sensor readings.

Removing the Sensor

When removing the sensor from the soil, do not pull it out of the soil by the cable. Doing so may break internal connections and make the sensor unusable.

What is Volumetric Water Content?

In very simplified terms, dry soil is made up of solid material and air pockets, called pore spaces. A typical volumetric ratio would be 55% solid material and 45% pore space. As water is added to the soil, the pore spaces begin to fill with water. Soil that seems damp to the touch might now have 55% minerals, 35% pore space and 10% water. This would be an example of 10% volumetric water content. The maximum water content in this scenario is 45% because at that value, all the available pore space has been filled with water. This soil is referred to as being saturated, because at 45% volumetric water content, the soil can hold no more water.

Calibrating the Sensor

The Go Direct Soil Moisture Sensor has a stored calibration that will give good results.

Specifications

Range:

0 to 45% volumetric water content in soil

Operating temperature

–40°C to +60°C

Dimensions

Dimensions: 8.9 cm × 1.8 cm × 0.7 cm (active sensor length 5 cm)

USB specification

2.0

Wireless specification

Bluetooth 4.2

Maximum wireless range

30 m (unobstructed)

Battery

300 mA Li-Poly

Battery life (single full charge)

~24 hours

Battery life (long term)

~500 full charge cycles (several years depending on usage)

Care and Maintenance

Battery Information

Go Direct Soil Moisture contains a small lithium-ion battery. The system is designed to consume very little power and not put heavy demands on the battery. Although the battery is warranted for one year, the expected battery life should be several years. Replacement batteries are available from Vernier (order code:
GDX-BAT-300).

Storage and Maintenance

To store Go Direct Soil Moisture for extended periods of time, put the device in sleep mode by holding the button down for at least three seconds. The red LED will stop flashing to show that the unit is in sleep mode. Over several months, the battery will discharge but will not be damaged. After such storage, charge the device for a few hours, and the unit will be ready to go.

Exposing the battery to temperatures over 35°C (95°F) will reduce its lifespan. If possible, store the device in an area that is not exposed to temperature extremes.

Water Resistance

Important: Go Direct Soil Moisture is water resistant but not waterproof. It should never be immersed in water.

If water gets into the device, immediately power the unit down (press and hold the power button for more than three seconds). Disconnect the sensor and charging cable, and remove the battery. Allow the device to dry thoroughly before attempting to use the device again. Do not attempt to dry using an external heat source.

Troubleshooting

For troubleshooting and FAQs, see www.vernier.com/til/20529

Repair Information

If you have watched the related product video(s), followed the troubleshooting steps, and are still having trouble with your Go Direct Soil Moisture, contact Vernier Technical Support at support@vernier.com or call 888-837-6437. Support specialists will work with you to determine if the unit needs to be sent in for repair. At that time, a Return Merchandise Authorization (RMA) number will be issued and instructions will be communicated on how to return the unit for repair.

Accessories/Replacements

Item Order Code

Micro USB Cable

CB-USB-MICRO

USB-C to Micro USB Cable

CB-USB-C-MICRO

Go Direct 300 mAh Replacement Battery

GDX-BAT-300

Warranty

Warranty information for this product can be found on the Support tab at www.vernier.com/gdx-sm/#support

General warranty information can be found at www.vernier.com/warranty

Contact Support

Fill out our online support form or call us toll-free at 1-888-837-6437.

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