Accelerometer

Equipment needed:

1.) 1 MicroBit with the battery pack (For wireless use)

2.) A computer or device that can store and transfer data

3.) A mounting device for the MicroBit to be placed onto the water bottle rocket

4.) A USB cable to connect the MicroBit (Used to download code onto the MicroBit)

 

We decided to use the microbit mini computer given by the univercity to measure the accelaration of our rocket. Learning to code wasn’t hard using microbit and we managed to pick it up fairly quickly so we started with the basic controls to use the accelerometer function and making a basic code which showed the acceleration of the computer at the time.

The microbit had worked but we realised we won’t be able to be plugged into the computer when we are testing the rocket, theis meant that we had to use other code to measure the speed of the rocket in a wireless way. That’s when we found that we can connect our phones to the microbit and live record the results, viewing them as they were being noted down.

So we switched to bluetooth to get the results of our Water Bottle Rocket

 

 

When we used bluetooth to measure the speeds of the rocket it was simpler to record the data and we could simply use the app for microbit to find the speeds at certain times. This let us efficiently use the microbit as accelerometer and record the data on a graph as the software gave us all the information automatically.

 

 

 

 

 

 

 

 

 

 

 

 

The graph shows the time on the x axis and velocity on the y axis . We found using this method to be easy to use and code so it is very good for begineers giving instant clear results as seen in the graph below so that students could very quickly find the results they were looking for. The waves and turbulence within the graph indicated that our rocket isnt perfectly aerodynamic but it isn’t too far off and for such a simple design and use it is very efficient. The turbulence can be attributed to the cone or the fins that we had used and improving the measurements of those will lead to better results.

 

In order to measure the velocity of the rocket we had the microbit set up so that it records the speed over time on the graph above. The velocity in the above graph was measured in cm/s and though the graph seems to fluctuate often it showed us that the rocket reaches a rough max speed of around 40 cm/s. This equates to around 0.4 metres per second giving us a great speed!

Although this is providing there is little wind and the bottle reaches its peek volumne capacity. Nevertheless travelling at 0.4 m/s means that in order to reach a height of 10m it would take approximately 20 seconds.

 

 

 

 

 

 

 

 

 

 

 

 

 

The Basic Setup:

1.) Connect the MicroBit into your computer and open “https://makecode.microbit.org/#editor” on your browser

2.) Write the code for your MicroBit to recieve and transfer data

3.) Unplug your MicroBit and connect it via bluetooth to your phone, once connected place the MicroBit into the mount on the rocket.

4.) Launch the rocket

5.) View the data on the MicroBit app and record it onto a graph