Vernier Software and Technology
Vernier Software & Technology
Tech Info Library

Can you create new match files for Logger Pro?

Logger Pro 3.5 and newer includes an automatic graph match generator. A button will automatically appear in the toolbar for "Graph match" whenever a Motion Detector is connected. To enable the feature for other sensors, choose Settings for (filename) from the File menu, and check the graph match option.

Logger Lite 1.4 also has this feature.

The legend will report the discrepancy between the match graph and the attempt. To display the legend, choose Legend from the Analyze menu. The discrepancy is the root mean square error (RMSE) between the two graphs, and is measured in the same units as the y axis. Smaller numbers mean a better match. In other words, the RMSE is a measure of how close, on average, the sensor graph is to the target graph.

TIL 1014: What are Mean Squared Error and Root Mean Squared Error? contains more information on interpreting the RMSE.

Most people can stop reading here. However, if you must use an older version of Logger Pro, consider the following instructions:

Method 1:
One way to create a match is to physically move an object to create a new graph to be matched. Open the Motion Detector file found in the Logger Pro experiment folder. Set up your Motion Detector and have a person or object ready to move in front of the Motion Detector. Click on Collect and collect the data. When you get a good run, choose Store Latest Run. Click on the vertical axis of the graph and make sure that the Run 1 data that you want to have matched is visible on the graph. There should be no data in Latest. Save the experiment file with a distinctive name. You are now ready to use this file as a new match file. Have students open the file and click on Start. New data will then be collected on top of the Run 1 data. Some teachers have one student group make up a challenge for the next group.

Method 2: (Logger Pro 3.4 and newer)
Use the Draw Prediction function in Logger Pro to sketch the target graph. To do this, connect a motion detector, launch Logger Pro, and let the autoID setup take place. You've got a position graph and a velocity graph. Delete one if you want. Delete the data table if you want. Choose Draw Prediction from the Analyze menu, and use the mouse to sketch a target graph. Save the file with a distinct name.

Method 3: (Using Logger Pro 2.1, 2.2, or 2.2.1)
Logger Pro 2.1 and newer contains distance match and velocity match experiment files. You can use manually entered data to create new match files. If the new file you want to create will have the same experiment length as one of the Logger Pro files, follow these instructions. If not, use method 4.
a) Open one of the match files that can be found in the set of Logger Pro experiment files. The two files are called Distance Match and Velocity Match.
b) Pull down the Window menu and choose Table Window at the bottom of the list.
c) You'll notice that the data table has two runs, Latest and Run 1. The graph that the students try to match comes from the Match column in Run 1. Notice that only a few numbers appear in this column. The program simply connects the points to create straight-line segments.
d) To create a new match, edit the numbers in the Match column. You can edit the cells by simply clicking a cell, entering a new value and pressing the Enter or Return key.
e) After entering these points, pull down the Window menu and choose the Graph Window.
f) Now save the file with a unique name.

Method 4:
If you want to create a file that has a different experiment length than the existing file, you'll have to take a few extra steps.
a) Open one of the match files that can be found in the set of Logger Pro experiment files. The two files are called Distance Match and Velocity Match.
b) After opening the file, click the x-axis maximum and enter a new time. This will change the length of the data collection.
c) Click the collect button and let the computer collect a new set of data.
d) Pull down the Data menu, choose Delete, and then select Run 1 from the list of runs. The match line segments will disappear.
e) Pull down the Data menu and choose Store Latest run.
f) Click the y-axis label. The Y-Axis Selection dialog box will appear. Make sure that only the following items are checked in this dialog box: Match for Run 2 and Distance (or Velocity) for Latest.
g) Pull down the Window menu and choose Table Window at the bottom of the list.
h) You'll notice that the data table has two runs, Latest and Run 1. The graph that the students try to match comes from the Match column in Run 1. When you deleted Run 1, the Match column was cleared out. You can now manually enter numbers in this column. You can edit the cells by simply clicking a cell, entering a new value and pressing the Enter or Return key. The program will draw straight-line segments between these points.
i) After entering these points, pull down the Window menu and choose the Graph Window.
j) Now save the file with a unique name.

Method 5:
You might want to challenge the students to match a mathematical function, e.g. 0.02*Time^2. This can be done by creating a calculated new column. The Distance Match 2 file is an example of such a file. Here are step-by-step instructions for this method:
a) Open one of the match files that can be found in the set of Logger Pro experiment files. The two files are called Distance Match and Velocity Match.
b) Pull down the Window menu and choose Table Window at the bottom of the list. You'll notice that the data table has two runs, Latest and Run 1. The graph that the students try to match comes from the Match column in Run 1. Notice that only a few numbers appear in this column. The program simply connects the points to create straight-line segments.
c) To replace these numbers with a function, start by pulling down the Data menu and choose Delete Column. Select the Match column.
d) Pull down the Data column, choose New Column, and then select Formula.
e) A dialog box will appear. Enter Match for the column name.
f) Click the Definition tab and enter the mathematical formula in the Equation field, e.g. 0.02*Time^2. Click OK.
g) Click the y-axis label. The Y-Axis Selection dialog box will appear. Make sure that only the following items are checked in this dialog box: Match for Run 2 and Distance (or Velocity) for Latest run.
h) Pull down the Window menu and choose the Graph Window.
i) Now save the file with a unique name.

Method 6:
You might want to mix straight-line segments and mathematical functions into the same match. For example you might want to have a horizontal segment followed by a short quadratic section. The Distance Match 3 file is an example of such a file. This is somewhat more difficult. To summarize, you will load one of the existing match files, copy part of the time data, apply a mathematical function to the time data in a spreadsheet program, and paste the edited values back into the Logger Pro. Here are step-by-step instructions for this method:
a) Open one of the match files that can be found in the set of Logger Pro experiment files. The two files are called Distance Match and Velocity Match.
b) Pull down the Window menu and choose Table Window at the bottom of the list.
c) You'll notice that the data table has two runs, Latest and Run 1. The graph that the students try to match comes from the Match column in Run 1.
d) Click and drag through the section of the Time column where you want the function to apply to. Pull down the Edit menu and choose Copy.
e) Open a spreadsheet program such as Excel and paste the contents of the clipboard into the first column of the spreadsheet.
f) In the second column of the spreadsheet enter a function into first cell of the second column using the first cell, e.g. =.05 * A1^2.
g) Copy this formula down the column.
h) Copy the contents of the second column and paste them into the appropriate section of the Match column in the Logger Pro data table.
i) Pull down the Window menu and choose the Graph Window.
j) Now save the file with a unique name.

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