Go Direct® Force and Acceleration Sensor (GDX-FOR)
Specifications and User Guide


  • Primary Test: Press the power button on the sensor to turn it on. (The red LED should flash.) Start the Graphical Analysis app on your device and select the sensor from the list of available sensors. (The green LED will start flashing.) Does the sensor read near zero when no force is applied? Does the sensor read a positive value when pulling, and a negative value when pushing? When placed on a flat surface with the label up, do the accelerations in the x- and y- directions read approximately zero, and does the acceleration in the z-direction measure -9.8 m/s2?
  • Force Sensor Test: Point the hook downward. With nothing attached, note the force reading. Then hang a 500 g mass from the hook and note the new reading. Is the difference approximately 4.9 N?
  • Was the force sensor properly zeroed? In general, before collecting data you should zero the force sensor in the orientation in which you want to use it, with no force applied. This additional step makes force measurements more accurate.
  • Were the accelerometers properly zeroed? For more accurate acceleration readings, zero the x- and y- directions of acceleration while the sensor rests horizontally on its top or bottom surface. Zero the z-direction of acceleration while the sensor rests horizontally on one of the long, rounded sides. Narrow “feet” on the rounded sides make this step easier.

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Go Direct Sensor always reads zero (or some other constant value).


  • Force range: ± 50 N
  • Accelerometer range: ± 156.8 m/s^2
  • Gyroscope range: ± 34.9 rad/s
  • Maximum wireless range: 30 m, unobstructed

The sensor is set to the stored calibration before shipping. However, the sensor may need recalibration at some time.
If you wish to calibrate the force sensor, you will conduct a two-point calibration.
First point: Remove all force from the sensor and hang it (or hold it) with the hook pointing down. Enter 0 N as the first known force.
Second point: Apply a known force to the sensor by hanging a mass from the hook on the end of the sensor. Enter the weight of the mass (Note: 1 kg applies a force of 9.8 newtons). We recommend using at least a 5 N weight for the second calibration point. Do not exceed 50 N of force during calibration.
If you wish to calibrate the acceleration sensors, see:
How do you calibrate an accelerometer?

Battery Troubleshooting
If the sensor can be turned on when connected by USB but not when disconnected from USB, the battery needs charging. Try charging the sensor for several hours.

If the sensor does not connect via Bluetooth or USB, and the charging LED is green immediately upon being plugged in to charge, the battery is either disconnected or dead. Use the video below to learn how to open the sensor case and check whether the battery is connected.

If the battery is not disconnected and you observe the sensor does not connect via Bluetooth or USB, and the charging LED is green immediately upon being plugged in to charge, the battery is dead. The battery will need to be replaced. The rechargeable battery in this sensor is covered by a one year warranty but should last two to five years in typical use.

Sensor dimensions
-Length: 7.6 cm, not including hook/bumper or hex rod attachment
-Width: 5.7 cm
-Height: 3.3 cm

Sensor Requirements
Go Direct Force and Acceleration Sensor uses Bluetooth low energy technology and can only be used wirelessly with devices that support Bluetooth low energy technology running the appropriate software. Otherwise, connect the sensor to your device using the included USB cable.

This sensor requires Graphical Analysis software on iOS, Android, Chrome, Windows, or Mac, or LabQuest 2 (model LQ2-LE only) or LabQuest 3.

Replacement Parts
Replacement Rod, 5 inch (ACC-ROD)
Go Direct® 300 mAh Replacement Battery (GDX-BAT-300)
Micro USB Cable (CB-USB-MICRO)
Micro USB to USB-C Cable (CB-USB-C-MICRO)
Dual-Range Force Sensor Replacement Parts Kit (DFS-RPK)

Related Vernier Products
Air Track Adapter (ATA-DFS)
Force Table Adapter (FTA-DFS)
Adapter for PASCO Cart (PCA-DFS)