pxt-calliope/docs/lessons/charting/activity.md
2016-04-28 11:47:59 -07:00

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Activity

Measure the acceleration on the micro:bit in the "x" direction.

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Welcome! This activity will teach how to use the micro:bit to chart the acceleration in the "x" direction. Let's get started!

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Let's measure acceleration (mg) in the "x" direction. Get the acceleration value (milli g-force), in one of three specified dimensions.

input.acceleration(Dimension.X)

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Use the plot bar chart to visualize the acceleration on the LED screen of the micro:bit in the specified range. You implement plot Bar Graph to display a vertical bar graph based on the "value" and "high" value. Then you must insert acceleration in the X dimension to measure the acceleration.

basic.forever(() => {
    led.plotBarGraph(input.acceleration(Dimension.X), 0)
})

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Notice that moving the micro:bit in the simulator from left to right (x direction) changes the values beneath the micro:bit in a range from 1023 to -1023 as measured in milli-gravities. By hovering over the micro:bit from left to right, you can observe changing values beneath the micro:bit simulator. Also, the LEDs shown on the Bar Graph fluctates based on the movement of the micro:bit simulator in the x direction. The line underneath the micro:bit simulator reflect the acceleration in the x direction.

NOTE: The colors of the charts reflect the color of the micro:bit simulator. In this instance, the micro:bit is yellow. So the color of the data line reflects the color of the micro:bit

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Vigorously move the micro:bit in the micro:bit simulatator by moving the micro:bit image from side to side. Every time the micro:bit moves in the x direction in the simulator, you are generating data points that can be reviewed in Excel. The more attempts to move the micro:bit from side to side, the more data being saved in Excel. After you have vigarously moved the micro:bit simulator from side to side for a sufficient amount of time, you are ready to graph or chart the accceleration of the micro:bit. We want a printout of our acceleration on Excel that can be graphed in Excel.

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We want to chart the data collected by using a tool in Excel.

The final part of this experiment is opening and reviewing the data in the Excel CSV file. Simply click on the line beneath the simulator. A CSV file will be generated to display the data points collected by moving the micro:bit in the X direction. Then click or tap on the data Excel file that was downloaded to your local Downloads Folder.

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First, click or tap on the first two columns (A, B) to include the time of the data being collected; b) the results of acceleration data on the micro:bit

Use the Recommended Charts command on the Insert tab to quickly create a chart thats just right for your data.

  • Select the data that you want to include in your chart.

  • Click Insert > Recommended Charts.

  • On the Recommended Charts tab, scroll through the list of chart types that Excel recommends for your data.

Click any chart type to see how your data will look in that format.

When you find the chart type that you want, click it, and then click OK. We want to select the chart called Line. A line chart is used to display trends over time. We will use the line chart because there are many data points over time.

Tip: If you dont see a chart type that you want, click the All Charts tab to see all of the available chart types.

  • Use the Chart Elements, Chart Styles, and Chart Filters buttons next to the upper-right corner of the chart to add chart elements like axis titles or data labels, to customize the look of your chart

  • Connect a micro:bit to your computer using your USB cable; compile; and repeat this experiment by moving the micro:bit in the "x" direction. Then collect and chart the data on Excel.
  • Review and analyze the actual micro:bit device data on Excel
  • Display acceleration with y or z using plot bar graph by changing acceleration from "x" to "y" or "z"

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Excellent, you're ready to continue with the challenges

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