Author: Yu Hang He Email: hey6@unlv.nevada.edu
Date: Last modified on <08/21/17>
Keywords: LabVIEW, NXT, Hitechnic Angle Sensor

The photo above depicts Hitechnic NXT Angle Sensor which allows you to measure axle rotational position and rotation speed. The Angle Sensor enables you to measure absolute angle, accumulated angle, and rotational speed. This tutorial shows you how to use LabVIEW to program Hitechnic NXT Angle Sensor and display the result on front panel and takes approximately 2 hours to complete.

This tutorial's motivation is to demonstrate how to program Hitechnic NXT Angle Sensor with LabVIEW. This tutorial assumes the reader has the following background and interests:

* Know how to program with LabVIEW. (LabVIEW Basic Tutorial)
* Know how to operate LEGO MINDSTORMS NXT.
* Perhaps also understand how to use LabVIEW MINDSTORMS module. (LabVIEW and NXT)
* This tutorial may also attract readers who want to use LEGO MINDSTORMS for instruction purpose.

The rest of this tutorial is presented as follows:

• Programming
• Example
• Final Words

To use LabVIEW to program Hitechnic NXT Angle Sensor, you must first installed LabVIEW module for LEGO MINDSTORMS. Follow this link for direction on how to install LabVIEW or the MINDSTORMS module.

To access block diagram nodes for Angle Sensor, go to Function Palette → MINDSTORMS Robotics → I/O → Additional Sensors → Hitechnic Sensors.

To receive inputs from Angle Sensor, use the HT Read node. The HT Read node is a polymorphic VI and Angle Sensor is one instance of the node. Click on the text box below the node to browse different implementations.

HT Read have four different implementations:

• Angle: returns the rotation position of a rotating axle from 0 – 359 degrees with 1 degree accuracy
• Total Angle: returns the accumulated number of degrees an axle has rotated
• RPM: returns the speed of the axle rotation in RPM (revolutions per minute)
• All Info: returns all three readings in a cluster structure

To reset the angle and accumulated angle, use the HT config node, which can be assessed under Hitechnic Sensors.
HT Wait For, which is also under Hitechnic Sensors group, can also be used to interact with Angle Sensor.

• Within 1 Degree: wait until Angle Sensor angle reading is within 1 degree of the targeted value
• Within 5 Degree: wait until Angle Sensor angle reading is within 5 degree of the targeted value
• Change: wait until Angle Sensor accumulated angle is more than the targeted value

Here is a simple example that displays the three sensor readings from Angle Sensor.

This tutorial's objective was to demonstrate how to use LabVIEW to program HiTechnic Angle Sensor. Once the concepts were conveyed the reader could use LabVIEW module for Lego MINDSTORM to program NXT and HiTechnic Angle Sensor.

For questions, clarifications, etc, Email: hey6@unlv.nevada.edu