Vernier Software and Technology
Vernier Software & Technology
Tech Info Library

Is there a way to connect my CO2 sensor to an NXT Mindstorm?

(This information refers to the LEGO NXT robotics system. The information should be similar for LEGO EV3. However, this has not been tested.)

There is a way to connect a CO2 sensor to an NXT mindstorm, but it will require that you are comfortable with a breadboard. You also need to be aware that the output will not be calibrated or reported in ppm. However, you will see a value rise and fall (counts) that is related to the CO2 level.

You will need to make an external power supply for the CO2 sensor. You can purchase a plastic battery case that holds 4 AA batteries from many different electronic vendors. This will serve as your power supply. You will also need a BTA-ELV adapter, a BB-BTA, a breadboard, and some jumper wires. The BTA-ELV is an adapter that will accept the BTA connector from the CO2 sensor. Connect the BTA-ELV to a breadboard. You can get a standard breadboard from many different electronic vendors. Next, place the BB-BTA on the breadboard next to the BTA-ELV. The BB-BTA is an adapter that will take the inputs from the breadboard back to a BTA cable. Using a jumper wire, feed the 0-5V signal input from the BTA-ELV (SIG1) over to the same pin (SIG1) on the BB-BTA using the breadboard. Next, tie the Grounds from the BB-BTA and the BTA-ELV together using a jumper wire and the breadboard. Now connect the 5V and GND outputs from the battery case to the breadboard. Using a jumper wire, feed these signals to the appropriate lines of the BB-BTA.

To run Vernier sensors with LEGO MINDSTORMS you must install our Vernier Sensor Block. The Vernier Sensor Block download, and all of the installation instructions can be found at:

Connect the BB-BTA to the NXT adapter. Connect the CO2 sensor to the BTA-ELV. Launch the NXT software.

After installing the Vernier Sensor Block, start a new project in the NXT Programming software. Drag and drop the Vernier Sensor Block into the programming environment. In the configuration window there is a control to select the Vernier Sensor. The CO2 sensor is not part of this list. Therefore, choose Raw Counts.

Below are links to the adapters that you will need

LEGO® MINDSTORMS® Education EV3 Core Set with Charger, order code LEGO-EV3-CORE, $412
NXT Sensor Adapter, order code BTA-NXT, $39
Vernier Engineering Projects with LEGO® MINDSTORMS® Education EV3 (Electronic Version), order code EP-EV3-E, $40
TIL 3339: LEGO® Mindstorms® EV3 Troubleshooting and FAQs

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