Vernier GDX-FOR Users guide

Go Direct®Force and Acceleration
(Order Code GDX-FOR)
Go Direct Force and Acceleration couples a 3-axis accelerometer with a stable and accurate force sensor that measures forces as small as ±0.1 N and up to ±50 N.
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

l Go Direct Force and Acceleration l Hook l Bumper l Nylon screw l Accessory rod l Micro USBCable

Compatible Software

See www.vernier.com/manuals/gdx-for for a list of software compatible with Go Direct Force and Acceleration.

Assembly

The hook and bumper attach to the sensor by screwing them into the post.
Hook attached
Getting Started
Please see the following link for platform-specific connection information:
www.vernier.com/start/gdx-for
Bluetooth Connection USB Connection
1. 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/ga4 for Graphical Analysis availability or www.vernier.com/downloads to update LabQuest App.
2. Charge your sensor for at least 2hours before first use.
3. Turn on your sensor by pressing the power button once. The Bluetooth LED will blink red.
4. Launch Graphical Analysis or turn on LabQuest.
5. If using Graphical Analysis, click or tap Sensor Data Collection. If using LabQuest, choose Wireless Device Setup > Go Direct from the Sensors menu.
6. 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 Bluetooth LED will blink green when it is successfully connected.
7. Click or tap Done. You are now ready to collect data.
8. This is a multi-channel sensor. To change the channel selections, see www.vernier.com/start/gdx-for
1. If using a computer or Chromebook, install Vernier Graphical Analysis. If using LabQuest, make sure LabQuest App is up to date. See www.vernier.com/ga4 for Graphical Analysis availability or www.vernier.com/downloads to update LabQuest App.
2. Connect the sensor to the USB port.
3. Launch Graphical Analysis or turn
®
on LabQuest. You are now ready to collect data.
4. This is a multi-channel sensor. To change the channel selections, see www.vernier.com/start/gdx-for
Note: This sensor does not work with the original LabQuest. It works with LabQuest 2 or LabQuest 3.
Bumper attached
Charging the Sensor
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.
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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.

Powering the Sensor

Turning on the sensor
Putting the sensor in sleep mode
Press button once. Red LED indicator next to Bluetooth icon flashes when unit is on.
Press and hold button for more than three seconds to put into sleep mode. Red LED indicator stops flashing when sleeping.

Connecting the Sensor

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.

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 Getting Started section of this user manual.

Channels

Go Direct Force and Acceleration has seven measurement channels. The channel names are
l Force l X-axis acceleration l Y-axis acceleration l Z-axis acceleration l X-axis gyro l Y-axis gyro l 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.

Collecting Data with Go Direct Centripetal Force Apparatus

Slide Go Direct Force and Acceleration 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.
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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:
l Z-axis gyro to capture angular velocity l X-axis acceleration for centripetal acceleration l Force for centripetal force
For additional information, refer to www.vernier.com/til/4258

Calibrating the Sensor

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.

Specifications

Response time 1 ms
Force range ±50 N
Acceleration range ±156.8 m/s
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
~10 hours continuous data collection
charge)
Battery life (long term) ~300 full charge cycles (several years depending
on usage)
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Care and Maintenance

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.

How the Sensor Works

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
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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/s2for 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/s 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.

Repair Information

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.

Accessories/Replacements

Item Order Code
Dual Range Force Sensor Replacement Parts Kit
Bumper and Launcher Kit
Accessory Ro d
Adap ter for Pasco Cart
Force Table Adapter
Go Direct Centripetal Force Ap paratus
Replacement Battery
Micro USBCable
USB-C to Micro USBCable
DFS-RPK BLK ACC-ROD PCA-DFS FTA-DFS
GDX-CFA
GDX-BAT-300 CB-USB-MICRO CB-USB-C-MICRO

Warranty

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

Disposal

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
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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.
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Federal Communication Commission Interference Statement

This equipment has been tes ted and found to comply with the li mits for a Class B digital dev ice, pursuant to Part 15 of the FCCrules . These li mits are desi gned to provide reasonable protection agains t harmful i nterference i n a residential ins tallation. This equipment generates, uses and c an radiate radio frequency energy and, i f not instal led and used in accordance wi th the instructions, may cause harmful interference to radio communic ations. However, there i s no guarantee that interference will not occur i n a particular i nstallati on. If this equipment does c ause harmful interference to radio or televi sion reception, whic h can be determined by turning the equipment off and on, the user i s encouraged to try to c orrect the interference by one or more of the foll owing measures:
Reorient or relocate the receivi ng antenna.
Increase the separation between the equipment and receiver.
Connect the equipment i nto an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an ex perienced radio/TV technic ian for help.
FCC Caution
This device compli es with Part 15 of the FCC Rules. Operation is subjec t to the fol lowing two conditions :
(1) this devic e may not cause harmful interference and
(2) this devic e must accept any interference received, incl uding interference that may cause undesired operation
RF Exposure W arning
The equipment c omplies with RF exposure l imits set forth for an uncontrolled environment. The antenna(s) used for this transmitter must not be co-located or operating in conj unction with any other antenna or transmitter. You are cautioned that changes or modifi cations not expressly approved by the party responsi ble for complianc e c ould v oid y our authority to operate the equi pment.

IC Statement

This device compli es with Industry Canada li cense-exempt RSS standard(s). Operation i s s ubject to the following two c onditions:
(1) this devic e may not cause interference, and
(2) this devic e must accept any interference, inc luding interference that may cause undesired operation of the devic e.
Industry Canada - ClassB This digi tal apparatus does not exceed the Class B limi ts for radio nois e emis sions from digi tal apparatus
as set out in the interference-causing equipment s tandard entitl ed “Digital Apparatus,” ICES-003 of Industry Canada. O peration is s ubject to the following two c onditions: (1) this devic e may not cause interference, and
(2) this devic e must accept any interference, inc luding interference that may cause undesired operation of the devic e.
To reduce potential radio interference to other us ers, the antenna type and its gai n shoul d be so chosen that the equivalent is otropical ly radiated power (e.i.r.p.) is not more than that permitted for succ essful communic ation.
RF exposure warning: The equi pment compli es wi th RF expos ure limi ts s et forth for an uncontrolled environment. The antenna(s) used
for this transmitter must not be c o-located or operating i n c onjunction with any other antenna or transmitter.
Le présent appareil est conforme aux CNR d’Industrie Canada applic ables aux appareils radio exempts de l icence. L’ex ploitation est autorisée aux deux conditi ons s uivantes :
(1) l’appareil ne doi t pas produire de brouillage, et
(2) l’appareil doit accepter tout interférence radioélectrique, même si c ela résulte à un brouill age sus ceptible d’en compromettre l e fonctionnement.
Cet appareil numérique respecte l es limi tes de bruits radioélectriques applicabl es aux appareils numériques de Clas se B prescrites dans la norme sur l e matériel interférant-brouill eur: “Appareils Numériques,” NMB-003 édictée par indus trie Canada. L’uti lisati on est soumi se aux deux c onditions suiv antes:
(1) cet appareil ne peut caus er d’interférences, et
(2) cet appareil doit accepter toutes i nterférences, y c omprises cell es s usceptibl es de provoquer un di sfonctionnement du dis positif.
Afin de réduire l es i nterférences radio potentiell es pour les autres uti lisateurs, le type d’antenne et son gain doi vent être choisi e de telle façon que l’ équivalent de pui ssance is otrope émis (e.i.r.p) n’es t pas plus grand que celui permis pour une communication établie.
Avertissement d’exposition RF: L’ équipement est conforme aux li mites d’exposi tion aux RF établi es pour un envi ronnement non
supervisé. L’antenne (s) utili sée pour c e transmetteur ne doit pas être jumelés ou fonc tionner en c onjonction avec toute autre antenne ou transmetteur.
Note: This product is a sensi tive measurement devic e. For best results, use the c ables that were provided. Keep the devic e away from
electromagnetic noise sources, such as microwaves, monitors, el ectric motors, and appliances.
13979 SW Millikan Way • Beaverton, OR 97005-2886
Vernier Software & Technology
Toll Free (888) 837-6437 • (503) 277-2299 • Fax (503) 277-2440
info@vernier.com • www.vernier.com
Rev. 3/ 29/2021
Go Direct, Vernier Graphical Analysis , LabQ uest, and other marks shown are our trademarks o r registered trademarks in the Unit ed States. Al l other marks n ot owned by us th at appear herein are t he p roperty of their respective owners, w ho may or may not be affil iated wit h, con nected to, or spons ored by us.
The Bluetooth®word mark and lo gos are regi stered trademarks owned by the Bluet ooth SIG, Inc. and any use of such marks by Vernier Software & Technol ogy is under license. Other trademarks and t rade names are those of their respective owners.
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