• Go Direct Force and Acceleration
• Hook
• Bumper
• Nylon screw
• Accessory rod
• 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.

The hook and bumper attach to the sensor by screwing them into the post.

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. This is a multi-channel sensor. Click SENSOR CHANNELS and select the channel(s) you want to use.
6. 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.

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

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

Charging	Orange LED next to battery icon is solid while sensor is charging.
Fully charged	Green LED next to battery icon solid when sensor is fully charged.

Turning on the sensor	Press button once. Red LED indicator next to Bluetooth icon 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-for

Connecting via Bluetooth

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

Connecting via USB

Connected and charging	Orange LED next to battery icon is solid when 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 battery icon is solid when sensor is connect 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 battery icon is solid when sensor is connected to charger via USB and the unit is charging. Green LED next to Bluetooth icon flashes when sensor is connected via Bluetooth.

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.

Channels

Go Direct Force and Acceleration has seven measurement channels. The channel names are

• Force
• X-axis acceleration
• Y-axis acceleration
• Z-axis acceleration
• X-axis gyro
• Y-axis gyro
• Z-axis gyro

Force

The default channel that is active when the sensor is connected is Force. The force channel measures pushes and pulls along the main axis of the sensor body. Use the hook attachment for pulling and the bumper attachment for pushing. Pulls are registered as positive forces and pushes are registered as negative forces, unless sensor readings are reversed in Graphical Analysis.

Acceleration

There are three acceleration channels, measured by a single chip, which is located under the 3-axis icon on the label. The icon shows the positive direction for each axis, with the x-direction of acceleration parallel to the pulling force on the force sensor and the z-direction straight up through the label. Each direction of acceleration can be measured separately.

If you choose to activate all three acceleration channels at once, you can create a calculated column for the total acceleration magnitude.

Gyroscope

Use the gyroscope channels to measure the rotation rate of the unit. Measured values are positive when the rotation is counter-clockwise relative to the axis directions indicated by the 3-axis icon on the label. For example, when placed label upward on a turntable rotating clockwise, the x- and y- gyroscopes will read close to zero and the z- gyroscope will show a negative reading.

If you choose to activate all three gyroscope channels at once, you can create a calculated column for the total magnitude of angular velocity.

Connect the Go Direct Force and Acceleration to the Centripetal Force Apparatus Sensor Bracket and slide it onto the Go Direct Centripetal Force Apparatus beam. Attach the mass carriage to the apparatus and secure the sensor at the desired location. As you turn the spindle to rotate the apparatus beam, the sensor will apply the force necessary to pull the carriage in a circular motion.

Channels

Turn on the sensor and connect it to Graphical Analysis on your device. Select the appropriate Go Direct Force and Acceleration data-collection channels in Graphical Analysis for your investigation:

• Z-axis gyro to capture angular velocity
• X-axis acceleration for centripetal acceleration
• Force for centripetal force

For additional information, refer to www.vernier.com/til/4258

Force

This sensor is factory calibrated. If you would like to calibrate the force sensor yourself, use a two-point calibration: no force applied and a known force applied. It is easiest to simply hang a mass from the hook. We recommend a 1 kg mass or greater. Do not exceed the maximum of 50 N during calibration.

Acceleration

This sensor is factory calibrated.

Gyroscope

This sensor is factory calibrated.

Response time	1 ms
Force range	±50 N
Acceleration range	±156.8 m/s2
Gyroscope range	±34.9 rad/s
Maximum sampling rate	1,000 samples/s
USB specification	USB 2.0 full speed
Wireless specification	Bluetooth v4.2
Maximum wireless range	30 m (unobstructed)
Dimensions	Length: 7.6 cm, not including the post or hook or bumper Width: 5.7 cm Height: 3.3 cm
Battery	300 mAh Li-Poly Rechargeable
Battery life (single full charge)	~10 hours continuous data collection
Battery life (long term)	~300 full charge cycles (several years depending on usage)

Battery Information

Go Direct Force and Acceleration 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 Force and Acceleration 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

Go Direct Force and Acceleration 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.

Force

The force channel uses strain gauge technology to measure force based on the bending of a beam in a load cell.

Accelerometer

The accelerometer is a microelectromechanical device (MEMS device) consisting of a cantilever and a test mass. As the mass is accelerated, the cantilever bends, generating a signal proportional to the acceleration. Three orthogonal axes provide three channels of acceleration information.

Gyroscope

The gyroscope is a microelectromechanical device that uses a vibrating structure to determine rate of rotation using the Coriolis force on the structure. Three orthogonal axes provide three different channels of rotation information.

Additional Information about Acceleration

Since the Accelerometer is sensitive to both acceleration and the Earth’s gravitational field, interpreting accelerometer measurements is complex. A useful model for understanding accelerometer measurements is a spring-based scale with a reference mass (or object) attached to the scale. If the scale is pointing upward (the usual orientation for such a device) the weight of the mass causes the spring to compress, and you get a non-zero reading. If you were to turn the scale upside down, the spring will be extended, instead of compressed, and we get a reading of the opposite sign. If you turn the scale so it points sideways, and keep it motionless, then the spring will just be at its relaxed length, and the reading will be zero. If you accelerated the scale toward the mass, then the spring would compress. If you accelerate the scale away from the mass the spring would stretch. In each case the scale is reading a value corresponding to the normal force on the mass. This reading can be made relative by dividing out the mass, giving units of N/kg, which is the same as m/s².

Q: What does an accelerometer measure?

A: Normal force per unit mass, otherwise known as proper acceleration.

Note that it’s not the net force per unit mass (which is acceleration), but it is the normal force per unit mass. This somewhat unusual quantity corresponds with what a rider on a roller coaster feels during the turns. This interpretation is useful even for the scalar total acceleration value, which is 9.8 N/kg for a 3-axis accelerometer at rest, zero for one in free fall, and greater than 9.8 for one rounding a corner.

This normal force interpretation works even for a one-axis accelerometer being accelerated in a horizontal direction. The reading is non-zero as the test mass inside the device has to have a force applied to accelerate it. That’s just a normal force that happens to be horizontal.

When discussing the accelerometer reading, we can call it the Normal Force per Unit Mass, with units of N/kg.

Q: I thought the Accelerometer measured acceleration!

A: Here we are being very careful to not call something an acceleration when it is not a kinematic acceleration. For example, an “acceleration” of 9.8 m/s² for an object that remains at rest is clearly a problematic interpretation, yet that’s what the accelerometer reads.

You can correct the Accelerometer reading to get a true acceleration by adding the component of the gravitational acceleration field along the direction of the sensor arrow. For example, if the axis of the accelerometer is pointing upward, then the gravitational component is –9.8 m/s². The Accelerometer reads 9.8 m/s² when the arrow is upward and the device is at rest. By adding –9.8 m/s², we get zero, which is the correct acceleration. If the arrow is horizontal, then the reading is zero, but the gravitational component is zero, and we still have zero for the true acceleration.

Q: What about g-force measurements?

A: We avoid the term g-force because the quantity doesn’t have units of force. Instead, g-factor can be used as a simplified label for Normal Force per Unit Mass in axis labels and discussions.

You can see that the g-factor is then 1 for an object sitting at rest on a table, zero in free fall, etc. The g-factor is dimensionless. If the Normal Force is a vector, then so is the g-factor. g-factor is completely optional–it is just a shortcut to avoid a long name.

For troubleshooting and FAQs, see www.vernier.com/til/3924

If you have followed the troubleshooting steps and are still having trouble with your Go Direct Force and Acceleration, 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
Dual Range Force Sensor Replacement Parts Kit	DFS-RPK
Bumper and Launcher Kit	BLK
Accessory Rod	ACC-ROD
Adapter for Pasco Cart	PCA-DFS
Force Table Adapter	FTA-DFS
Go Direct Centripetal Force Apparatus	GDX-CFA
Replacement Battery	GDX-BAT-300
Micro USB Cable	CB-USB-MICRO
USB-C to Micro USB Cable	CB-USB-C-MICRO

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