Go Direct^® Soil Moisture Sensor (GDX-SM)

Specifications and User Guide

Some versions of this sensor support Remote Data Logging.
Which Go Direct Soil Moisture sensor do I have? Does it support Remote Data Logging?

Troubleshooting

General: Press the power button on the sensor to turn it on. Connect your sensor as described in the Getting Started instructions for your device.

• Primary Test: In air, the Go Direct Soil Moisture Sensor should read somewhere between -5% and -50%. Grab the sensing portion with your hand, and the reading should go up to somewhere between 10% and 50%.

Additional Troubleshooting

• Which Vernier sensors are submersible in water?
• Remote Data Logging Troubleshooting and FAQs
• How do I check the status of my sensor during a remote data logging experiment?
• How do I bring remote logging data from multiple devices or multiple runs into a single Graphical Analysis file?

REMOTE DATA LOGGING

• Which Go Direct Soil Moisture sensor do I have? Does it support Remote Data Logging?
• Is there a way to update Go Direct sensors with the remote data logging feature?
• Remote Data Logging Troubleshooting and FAQs
• How long will my battery last for my remote data logging experiment?
• Which sensors are equipped with the remote data logging feature?
• How do I check the status of my sensor during a remote data logging experiment?
• How do I bring remote logging data from multiple devices or multiple runs into a single Graphical Analysis file?

Specifications

• Range: 0 to 45% volumetric water content in soil
• Operating temperature: –40°C to +60°C
• Dimensions: 8.9 cm × 1.8 cm × 0.7 cm (active sensor length 5 cm)
• Connections:
  ⚬ Wireless: Bluetooth^® v4.2 (wireless range 30 m unobstructed)
  ⚬ Wired: USB 2.0 full speed
• Battery: 300 mA Li-Poly
  ⚬ Battery Life (single, full charge): ~24 hours continuous data collection
  ⚬ Battery Life (lifetime): 2 – 5 years (typical)

Calibration

Calibrate? No. The Go Direct Soil Moisture Sensor has a stored calibration that gives good results.

Battery Troubleshooting

1. If the sensor can be turned on when connected by USB but not when disconnected from USB, the battery either needs charging or has reached its end of life and can no longer hold a charge.
   ⚬ First, try charging the sensor for several hours.
2. If the sensor still won’t turn on when disconnected from USB, try swapping the battery with a working sensor to see if the problem follows the battery or stays with the sensor.
   ⚬ If the problem stays with the sensor, the battery is probably not the issue.
   ⚬ If the problem follows the battery, the battery has likely reached its end of life.
3. If you intend to use this sensor wirelessly, its battery will need replacing.
   Go Direct® 300 mAh Replacement Battery (GDX-BAT-300)
4. See How do I remove or replace a Go Direct battery? for more information (including a video).

Rechargeable batteries are covered by a one-year warranty.
Batteries should last two to five years in typical use.