Seismograph Challenge

Coding challenges for the seismograph.

What you’ll need:

• micro:bits (2)
• micro USB cables (2)
• Plate
• Tape
• Scissors

Before we get started

Complete the seismograph activity and your code will look like this:

basic.forever(() => {
    led.plotBarGraph(input.acceleration(Dimension.Strength) - 1023, 0);
});

Computer Science Steps

1.

We want to simply detach the blocks from the recent activity. We will use blocks from the activity to create a brand new program to show the way micro:bit devices communicate through the BLE (Bluetooth low energy) radio.

basic.forever(() => {
    led.plotBarGraph(input.acceleration(Dimension.Strength) - 1023, 0);
});

2.

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.

We need add send number block found in the Radio drawer. We will attach send number to acceleration and subtract the gravity from acceleration strength.

Your finished code will look like this:

radio.sendNumber(input.acceleration(Dimension.Strength) - 1023);

3.

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. We need attach forever loop to send number.

Your finished code will look like this:

basic.forever(() => {
    radio.sendNumber(input.acceleration(Dimension.Strength) - 1023);
});

4.

We want to register code to run when a packet is received over radio. We can implement this code by adding on data receivedblock found in the radio drawer.

Your finished code will look like this:

basic.forever(() => {
    radio.sendNumber(input.acceleration(Dimension.Strength) - 1023);
});
radio.onReceivedNumber(function (receivedNumber) {
});

5.

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.

Your finished code will look like this:

basic.forever(() => {
    radio.sendNumber(input.acceleration(Dimension.Strength) - 1023);
});
radio.onReceivedNumber(function (receivedNumber) {
    led.plotBarGraph(receivedNumber, 0);
});

Science Steps

6.

First, notice that moving the 1st micro:bit in the simulator in any direction, you will change the acceleration value of the 2nd micro:bit. Also, notice that by moving the micro:bit simulator, there is a changing acceleration value of the second micro:bit. Second, the flat colored horizontal line will start a waving line on the 2nd micro:bit to display the value of the strength as measured in milli-gravities. Finally, notice that the LED display will fluctate based on the movement of the 2nd micro:bit simulator.

7.

Connect the 2nd micro:bit to your computer using your USB cable. We should have two micro:bit devices attached to the computer.

8.

Click or tap the Download button for the seismograph program to run the program on the 1st micro:bit and 2nd micro:bit.

9.

The black lines should appear directly beneath the colored lines. The black lines measure the micro:bit acceleration. And the colored lines measures micro:bit simulator acceleration.

Run the acceleration experiment by vigarously moving the plate in any direction or move the object below the micro:bit (such as a table).

Every time the micro:bit moves in any direction, you generate data points that can be reviewed in Excel later. The more attempts to move the micro:bit, the more data to be reviewed in Excel. Notice that the LED on the 2nd micro:bit changes to communicate the movement of the 1st micro:bit.

Now we are ready to graph or chart the accceleration of the micro:bit. We want a printout of the micro:bit acceleration graphed in Excel.

10.

In order to receive the the data plotted by Excel, click or tap anywhere in the on the chart data.

11.

You have two options to Analyze Data:

• Local File: Save the data to your local Downloads folder and open it in Excel.
• Stream to Cloud: Upload your data to Microsoft Azure to analyze it.

Click or tap Download data

12.

A CSV file will be generated to display the data points collected by the micro:bit. Click or tap on the data Excel file that was downloaded to your local Downloads Folder.

13.

Select the data that you want to include in your chart. The chart should include the first two columns: time and acceleration.

Click or tap on the first two columns (A, B) to include time and acceleration data from the micro:bit. We only need the first two columns (A, B) because the 2nd micro:bit changes have been communicated by the 1st micro:bit. So the data points of the seismograph are being recorded on the 1st micro:bit.

14.

Click or tap on Insert then select Recommended Charts. We can select a chart that’s just right for the data.

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

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.

Click on the 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.

Tip: If you don’t see the line chart, click the All Charts tab to see the line chart.

15.

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

Alternatively, click or tap on the Design Ribbon.

Let’s select Style 10 as an example.

• Have fun reviewing your seismograph data and analyzing the acceleration with Excel.
• The first person and second person take shaking or moving the micor:bit in any direction while the other player charts the data on the micro:bit!
• Review and analyze the actual micro:bit device acceleration data on Excel

radio