Studying accelerated motion: an excuse to know how to implement

data loggingUPNA

Public University of Navarra

The problem….

• How accelerated motion can be easily produced?

• How can accelerated motion be measured and verified?

• Which role do the NXT and the PC play in the solution?

A vehicle without motor and one sonar…

A vehicle without motor and one sonar…

Measuring distances to wall in a slope…

How can accelerated motion be easily produced?

•The acceleration is given by the component of the vehicle weight which is parallel to the inclinated plane

• This component is the projection of the gravity acceleration (g) parallel to the plane

• The other component, orthogonal to the plane, is compensated by its static reaction

How can accelerated motion be measured and verified?

• The sonar sensor gives the increasing measure of the distance between a fixed obstacle (at the starting point of the motion) and the moving vehicle (see previous figure)

• We have to read regularly the sonar produced values and to verify the quadratic relation plot of these values with respect to the time

• So we need to make what we call a “data logging”…

• The manual version (with a timer) is hard to be done with enough precision…

• We do not know how to send every value to the PC during the motion…

• So the automatic data logging provides a reasonable way to store the read values into a file inside the NXT and sending them to the PC after the end of the experiment

Program…

Uploading…

Exploiting results…

Exploiting results…

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The theory…..

The mesures…..

Dis

tan

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Time

displacement velocity

Which is the role do the NXT and the PC play in the solution?

•The NXT is the real data logger

•The PC is used for analysing & visualizing purposes

Activity to do…

1. Choose one or more sensors

2. Choose one situation where data logging is necessary or interesting

3. Design and implement one mini didactical unit arounf this activity