• Go Direct Surface Temperature
• Micro USB Cable

Choose a platform below to see its compatibility requirements.

LabQuest

Interface	LabQuest App
LabQuest 3	Full 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
Interface	Graphical Analysis
No interface required	Full support 1
LabQuest 3	Full 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
Interface	Graphical Analysis
No interface required	Full support
LabQuest 3	Full 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
Interface	Graphical Analysis	Graphical Analysis GW
No interface required	Full support	Full support
LabQuest 3	Full support 1 2	Full support 1 2
LabQuest 2 (discontinued)	Full support 1 2 3	Full 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
Interface	Graphical Analysis	Graphical Analysis GW
No interface required	Full support	Incompatible
LabQuest 3	Full support 1 2	Full support 1
LabQuest 2 (discontinued)	Full support 1 2 3	Full 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
Interface	Python
No interface required	Full support

Javascript

	Software
Interface	Javascript
No interface required	Full 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
Interface	NI LabVIEW
No interface required	Full 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.

Please see the following link for platform-specific connection information:

www.vernier.com/start/gdx-st

Bluetooth Connection

USB Connection

Install Vernier Graphical Analysis® on your computer, Chromebook™, or mobile device. If using LabQuest®, make sure LabQuest App is up to date. See www.vernier.com/ga for Graphical Analysis Pro availability or www.vernier.com/downloads to update LabQuest App. Charge your sensor for at least 2 hours before first use. Turn on your sensor by pressing the power button once. The LED will blink red. Launch Graphical Analysis or turn on LabQuest. If using Graphical Analysis, click or tap Sensor Data Collection. If using LabQuest, choose Wireless Device Setup > Go Direct from the Sensors menu. Select your Go Direct sensor from the list of Discovered Wireless Devices. Your sensor's ID is located near the barcode on the sensor. The LED will blink green when it is successfully connected. Click or tap Done to enter data-collection mode.

Install Graphical Analysis on your computer or Chromebook. If using LabQuest, make sure LabQuest App is up to date. See www.vernier.com/ga for software availability or www.vernier.com/downloads to update LabQuest App. Connect the sensor to the USB port. Launch Graphical Analysis or turn on LabQuest. You are now ready to collect data.   Note: This sensor does not work with the original LabQuest. It works with LabQuest 2 or LabQuest 3.

Connect Go Direct Surface Temperature to the included Micro USB Cable and any USB device for two hours.

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

Charging	Blue LED on steady while sensor is connected to the Charging Cable or Charging Station.
Fully charged	Blue LED is off when charging is complete.

Turning on the sensor	Press button once. Red LED indicator flashes when 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 stops flashing when sleeping.

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

www.vernier.com/start/gdx-st

Connecting via Bluetooth

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

Connecting via USB

Connected and charging	Blue and Green LED solid when sensor is connected to Graphical Analysis via USB and unit is charging. (Green LED is obscured by the blue one.)
Connected, fully charged	Green LED solid when sensor is connected to Graphical Analysis via USB and the unit is fully charged.
Charging via USB, connected via Bluetooth	Blue LED is solid and green LED is flashing, but the green flashing LED looks white because it is overwhelmed by the blue.

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

Connect the sensor following the steps in the Getting Started section of this user manual.

Important: Go Direct Surface Temperature is for use in air and water only. For temperature measurements in harsher environments that require a more durable probe, we recommend our Go Direct Temperature (order code GDX‑TMP).

It should not be necessary to perform a calibration when using this sensor. It is calibrated before it ships.

Temperature range	–25 to 125°C
Maximum temperature that the sensor can tolerate without damage	150°C
Temperature sensor	20 kΩ NTC Thermistor
Accuracy	±0.5°C or better
Response time from 25°C to 100°C in water	5 seconds
Probe dimensions: probe length (handle plus body)	Handle: 7 cm high, 3.5 cm wide, 2 cm deep Cable: 1 m Submergible section: 7 cm

Battery Information

Go Direct Surface Temperature contains a small lithium-ion battery in the handle. 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 Surface Temperature 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

The body of the Go Direct Surface Temperature Sensor is not water resistant and 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.

This probe uses the 20 kΩ NTC Thermistor, which is a variable resistor. When the temperature increases, the resistance decreases non-linearly. The best-fit approximation to this nonlinear characteristic is the Steinhart-Hart equation. At 25°C, the resistance is approximately 4.3% per °C. The interface measures the resistance value, R, at a particular temperature and converts the resistance using the Steinhart-Hart equation:

T = [K₀ + K₁(ln 1000R) + K₂(ln 1000R)³]^-1 – 273.15

where T is temperature (°C), R is the measured resistance in kΩ, K_o =1.02119 × 10^-3, K₁ = 2.22468 × 10^-4, and K₂ = 1.33342 × 10^-7. Our programs perform this conversion and provide readings in °C (or other units, if you load a different calibration).

First check that the sensor is responding: Connect the sensor and start the data‑collection program. Hold the tip of the sensor in your hand to warm it and check that the temperature changes.

For additional troubleshooting and FAQs, see www.vernier.com/til/4052

If you have followed the troubleshooting steps and are still having trouble with your Go Direct Surface Temperature, 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.

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

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

When disposing of this electronic product, do not treat it as household waste. Its disposal is subject to regulations that vary by country and region. This item should be given to an applicable collection point for the recycling of electrical and electronic equipment. By ensuring that this product is disposed of correctly, you help prevent potential negative consequences on human health or on the environment. The recycling of materials will help to conserve natural resources. For more detailed information about recycling this product, contact your local city office or your disposal service.

Battery recycling information is available at www.call2recycle.org

Do not puncture or expose the battery to excessive heat or flame.

The symbol, shown here, indicates that this product must not be disposed of in a standard waste container.