Thermal Infrared NXT Sensor

Based on a MLX90614 non-contact thermometer, this thermal infrared camera for Lego Mindstorms NXT robots reads surface temperature of objects by detecting their infrared radiation.

The Thermal Infrared Sensor for Lego Mindstorms NXT robots reads both the ambient temperature (the temperature of the air around the sensor) and the surface temperature of the object that the sensor is pointed towards.The sensor can detect a flame at a range of 2 meters.

When measuring temperatures greater than room temperature, be sure to hold the sensor at a sufficiently safe distance from the heat source. For example, holding the sensor within 1-2 cm of a hot source is fine, but touching the sensor with the hot source may damage the sensor.

Technical specifications of the Thermal Infrared Sensor for Lego Mindstorms NXTrobots

The technical specification of the Thermal Infrared Sensor for Lego Mindstorms NXT robots from Dexter Industries are as follows:

• Reads object temperatures between -90°F and 700°F (-70°C and +380°C)
• Precision : 0,5°C
• Resolution : 0,02°C
• The Thermal Infrared Sensor uses the I2C protocol to communicate with the Lego Mindstorms NXT  intelligent brick.
• The Thermal Infrared Sensor can be placed on any of the four sensor ports of the NXT.

For advanced users, you can re-write the firmware for the Thermal Infrared Sensor using the ISP connectors with an AVR adapter such as the AVRISP mkII.

Structure of the Thermal Infrared sensor for Lego Mindstorms NXTrobots

The image below shows the main components of the Thermal Infrared Sensor for Lego Mindstorms NXT robots from Dexter Industries.

Programming the Thermal Infrared Sensor for Lego Mindstorms NXTrobots

All the source code from Dexter Industries are available at the following address : http://www.dexterindustries.com/download.html

Programming the Thermal Infrared Sensor for Lego Mindstorms NXT robots using NXT-G

Two NXT-G blocks are available to program the NXT Thermal Infrared Sensor. The first NXT-G block allows you to read both the temperature of the pointed object and the room temperature. The second NXT-G block aim is to adjust the emissivity. While most objects do not require an adjustment of the emissivity, some polished metals require this adjustment for a correct reading of the temperature. NXT-G blocks are available from the downloads page at Dexter Industries web site: http://www.dexterindustries.com/download.html#TIR

Programming the Thermal Infrared Sensor for Lego Mindstorms NXT robots using RobotC

The Thermal Infrared Sensor for NXT can be programmed using RobotC. Sample RobotC code to read the temperature of an object, to read the ambient temperature and read and write the emissivity is available at this address: Example of RobotC code for the Thermal Infrared Sensor.

Programming the Thermal Infrared Sensor for Lego Mindstorms NXT robots using Labview

Labview VI’s for the Dexter Industries Thermal Infrared Sensor can be found here: Dexter_Industries_TIR_For_Labview.zip