pxt-calliope/docs/lessons/charting/acceleration.md
Michael Elliot Braun 0b8142ae73 update acc
2016-04-25 15:54:28 -07:00

120 lines
6.2 KiB
Markdown

# charting activity
Measure the acceleration on the micro:bit in the "x" direction.
### ~avatar avatar
Welcome! This activity will teach how to use the micro:bit to chart the second micro:bit's acceleration in the "x" direction. Let's get started!
### ~
Let's measure `acceleration (mg)` in the "x" direction. Get the acceleration value (milli g-force), in one of three specified dimensions.
```blocks
input.acceleration(Dimension.X)
```
### ~
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.
```blocks
basic.forever(() => {
led.plotBarGraph(input.acceleration(Dimension.X), 0)
})
```
### ~
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
![](/static/mb/data4.png)
### ~
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.
### ~
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.
![](/static/mb/data3.png)
### ~
* Review and write down your observations from the Excel data.
* Chart the data collected by using a graph in Excel
* Connect a micro:bit to your computer using your USB cable; compile; and move the micro:bit in the "x" direction.
* Review and analyze the actual micro:bit device data on Excel
### ~avatar avatar
Welcome! The activity will teach you how to use the acceleration of the 1st micro:bit and to visualize the acceleration on the 2nd micro:bit. Let's get started!
### ~
Let's measure `acceleration (mg)` and then `send number`. `Acceleration` is measured in **milli-gravities**, so a value of -1000 is equivalent to -1g or -9.81m/s^2. We will be able to get the acceleration value (g-force), in the specified "x" dimension. `Send number` will broadcast a number data packet to other micro:bits connected via radio.
```blocks
radio.sendNumber(input.acceleration(Dimension.X));
```
### ~
We want to display the acceleration forever. In order to do so, we need a `forever` loop. A forever loop will repeat code in the background forever.
```blocks
basic.forever(() => {
radio.sendNumber(input.acceleration(Dimension.X));
});
```
### ~
We want to register code to run when a packet is received over radio. We can implement this code by adding `on data received`.
```blocks
basic.forever(() => {
radio.sendNumber(input.acceleration(Dimension.X))
})
radio.onDataReceived(() => {
})
```
### ~
Finally, we want to chart the acceleration. So we must first implement `plot bar graph`. `Plot Bar Graph` will display a vertical bar graph based on the value and high value. In order to transfer the receive the number from the 1st micro:bit, we must implement `receive number` to constantly display a vertical bar graph based on the value. Remember, the value will equal to the micro:bit's acceleration in the "x" direction.
```blocks
basic.forever(() => {
radio.sendNumber(input.acceleration(Dimension.X))
})
radio.onDataReceived(() => {
led.plotBarGraph(radio.receiveNumber(), 1023)
})
```
### ~
Notice that moving the micro:bit the farthest direction in the x direction will be -1023 on the charting beneath the simulator. The second observation will be that the LEDs will be full brightness on the 2nd micro:bit. There is a single LED turned on with the 1st micro:bit. Additionally, the graphs will reflect 0 acceleation for the 1st micro:bit. In this scenario, if you are adjusting the acceleration in the simualator, you are also changing your chart that will be produced.
![](/static/mb/acc.png)
### ~
NOTE: The colors of the charts reflect the color of the micro:bit simulator. In this instance, the micro:bits are blue and green. So the colors of the line graphs reflect the colors of the micro:bit
### ~
After running this simulatation several seconds by moving the micro:bit side to side in the x direction, you are ready to graph or chart the accceleration of the micro:bit. We want a printout of our acceleration on Excel. We will graph the fluctuating acceleration of the simulation experiment.
![](/static/mb/acc2.png)
### ~
Finally, you must open the Excel CSV file by clicking on the data.xls file that was downloaded to Downloads Folder.
![](/static/mb/data3.png)
### ~
Have fun reviewing your simulation and analyze the acceleration by chart the Excel data using Excel.
* Connect the first micro:bit to your computer using your USB cable and run the charting script on it.
* Connect the second micro:bit to your computer using your USB cable and run the charting script on it.
* The first person and second person take turns tilting the micro:bit in the "x" direction while the other player charts the data on the micro:bit!
* Review and analyze the actual micro:bit device acceleration data on Excel