Tuesday, January 14, 2014

TI-84 with CBR - how to turn off Auto Scale

I was recently asked, "How do you turn off 'Auto Scale' on a TI-84?" So I made a video to explain this. It also helps answer the question "how do you connect a CBR to your computer so that it will display on the TI-84 SmartView emulator?"
 YouTube video link
You may have noticed when you plug in a CBR2 using the mini-USB it automatically launches EasyData app. You can then just press ‘soft key’ for “Start” and a graph of the data shows up in real-time. However, if you are not moving, the auto scale makes it look like a jagged graph. This may be confusing to students. “If I wasn’t moving, why does my graph look like I was.” They may not realize that the y scale is only over a few millimeters, and this shows the amount of precision that the motion detector is able to account for as it determines the distance sound reflects off of a surface. “Attend to precision” is an important mathematical practice.
Not all of the modes do this auto-scaling. Distance Match does not auto scale. 

The scale can be changed after the data is collected, but the following demonstrates how to make it so that this is not necessary. Good news: Once this has been done, the setting will not need to be changed again for that TI-84. Press “Setup” and choose “2: Time Graph…”

Choose “Adv” for the advanced settings. Then “Edit” to change the “Auto Scale After Collect” to “No.”

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