Vernier Software and Technology
Vernier Software & Technology

Go Direct® Colorimeter User Manual

Go Direct® Colorimeter

Go Direct Colorimeter is used to determine the concentration of a solution by analyzing its color intensity. The cuvette slot is designed to accommodate most cuvettes with a 10 millimeter path length. The Colorimeter measures the amount of light transmitted through a sample at a user-selectable wavelength. You may choose from four wavelengths: 430 nm, 470 nm, 565 nm, and 635 nm.

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

  • Go Direct Colorimeter
  • 15 polystyrene cuvettes and 15 plastic cuvette lids
  • Micro USB cable

Compatible Software

Getting Started

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

Bluetooth Connection

USB Connection

  1. Install Graphical Analysis 4 on your computer, Chromebook™, or mobile device. See for software availability.
  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 4.
  5. Click or tap Sensor Data Collection.
  6. Click or tap 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 to enter data-collection mode.
  1. Install Graphical Analysis 4 on your computer or Chromebook. If using LabQuest 2, make sure LabQuest App is up to date. See for software availability or to update LabQuest App.
  2. Connect the sensor to the USB port.
  3. Launch Graphical Analysis 4 or turn on LabQuest 2. You are now ready to collect data.

Charging the Sensor

Connect the Go Direct Colorimeter to the included USB Charging Cable and any USB device for two hours.

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


Orange LED next to the battery icon is solid while the sensor is charging.

Fully charged

Green LED next to the battery icon is solid when the sensor is fully charged.

Providing Power

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.

Connecting the Sensor

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

Connecting via Bluetooth

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

Connecting via USB

Connected and charging Orange LED next to the battery icon is solid when the 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 the battery icon is solid when the sensor is connected 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 the battery icon is solid when the sensor is charging. Green LED next to the Bluetooth icon flashes.

Using the Product

Connect the sensor following the steps in the Getting Started section of this user manual. After connecting the sensor, the following steps must be completed prior to starting data collection.

  1. Press the < or > button on the Colorimeter to select the correct wavelength for your experiment (430 nm, 470 nm, 565 nm, or 635 nm).
  2. Allow the Colorimeter to warm up for about five minutes before calibrating.
  3. Calibrate the Colorimeter.
    1. Slide the lid of the Colorimeter open to reveal the cuvette slot.
    2. Insert a cuvette, filled with distilled water or other solvent used to prepare your solutions, for your calibration blank (100% transmittance or 0 absorbance).
      Important: Line up one of the clear sides of the cuvette with the arrow at the right side of the cuvette slot. Slide the Colorimeter lid closed.
    3. Press the CAL button on the Colorimeter to begin the calibration process. Release the CAL button when the red LED begins to flash.
    4. When the red LED stops flashing, the calibration is complete. The absorbance reading should be very close to 0.000 (100%T).
    5. Remove the blank cuvette from the Colorimeter.
  4. Continue with data collection.


Calibration is required for use. See the Using the Product section for instructions.


Colorimeter range

0 to 3 (absorbance) (0 to 100% T)

Useful range

0.05 to 1.0 absorbance (90% to 10% T)


430 nm, 470 nm, 565 nm, 635 nm

Care and Maintenance

Battery Information

Go Direct Colorimeter 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 Colorimeter 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 Colorimeter 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

Light from an LED light source passes through a cuvette containing a solution sample. Some of the incoming light is absorbed by the solution. As a result, light of a lower intensity strikes a photodiode.


Here are some tips for best data-collection practices:

  • Allow the Colorimeter to warm up for about 5 minutes before calibrating.
  • Fill a cuvette two-thirds to three-fourths full with liquid, including the calibration blank, so that the light travels through the liquid reliably.
  • After filling a cuvette with liquid, seal the cuvette with a cap to prevent spills.
  • Make sure to place a cuvette in the Colorimeter so the path of the light source travels through the clear sides of the cuvette. An arrow to the right of the cuvette slot shows the light path.
  • For best results, use one cuvette to make all your measurements for a given experiment.
  • If you calibrate a Colorimeter and then change the wavelength, calibrate the Colorimeter again to ensure the proper identification of the new wavelength.

For best results, a sample's absorbance or transmittance values should fall within these ranges:

  • percent transmittance:10–90%
  • absorbance: 0.05–1.0

Beer’s law experiment results begin to lose their linearity at absorbance values above 1.0 (percent transmittance values less than 10%). If you have a solution that transmits such a low level of light, consider diluting the solution so that it falls within this range.

Repair Information

If you have followed the troubleshooting steps and are still having trouble with your Go Direct Colorimeter, contact Vernier Technical Support at 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.



Vernier warrants this product to be free from defects in materials and workmanship for a period of five years from the date of shipment to the customer. This warranty does not cover damage to the product caused by abuse or improper use. This warranty covers educational institutions only.


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

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.

Contact Support

Fill out our online support form or call us toll-free at 1-888-837-6437.

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