Overview

Mini-Me II is a project that takes advantage of the Integrated Micro-Electromechanical Systems (I-MEMS) technology to create a system that tracks human motion in two

dimensions and reproduces it using a three dimensional model and the Lego NXT

robot. The system is divided into three parts that will respectively manage the input and processing of data, the user interface, and the robot control.

What is I-MEMS?

Integrated Micro-Electromechanical Systems are small integrated devices or systems that combine electrical and mechanical components into a single integrated circuit.

What is an accelerometer? Accelerometer is a device used to measured linear acceleration without an external reference.

Capacitive Micromachined Accelerometer A change in acceleration causes a change in the space between the moving and fixed electrodes of a capacitive accelerometer. The resulting output frequency is proportional to the applied acceleration.

Data Acquisition

Calculating Angles:

Particular angles have a corresponding voltage as shownin the figure below.

Lego NXT Robot

LabVIEW and 3D Animation

Mini-Me IITeam 11: Rufino Ayala, Antonio Farias, Shahzeb Nasir, Carlos J. Restrepo

University of Houston – Cullen College of Engineering

What is 3D picture control?

The LabVIEW 3D Picture Control Software is a set of free tools for LabVIEW that allows the modeling and rendering of basic 3D scenes in the LabVIEW environment. The 3D models are created in a 3D graphics software and exported into LabVIEW in the WRL file format. After the objects have been imported, LabVIEW provides functions to rotate, scale, and translate each object in the scene.

Angles are obtained from the DAQ and conditioning module and then scaled to apply the correct angle rotation as shown in the figure below.

Scale Angle Rotate

LimbsDisplay 3D

Angle

5

Scaled

Angle

5

Data

3D

Done

3D Animation Controller

NXT Motors

RCX Motors

Multiplexer

Data Acquisition

LabVIEW 3D Animation

Lego NXT

DAQ FIlterVoltage

to Angle

5 5

Signal Angle

5

Signal Conditioning and Angle Determination

Sensor Rotation

Using the built in shaft encoder the motor is able to move precisely to the appropriate angle.

Due to the lack of a shaft encoder, the desired angle is achieved by varying the power to the motors.

Provides additional functionality to the NXT brick by expanding the number of motors that can be controlled.

- NXT

MotorsAngle to shaft

positionShaft

encoder

NXT Motor Controller

Angle

3

Previous Angle

!Angle

3

3

NXT Done

3

RCX

Motors

Angle to power

MUX

RCX Motor Controller

Angle

2

Power Level

2

RCX Done

2