Seismometers are both useful and precise when it comes to measuring earthquakes or tremors. In humanity’s ongoing efforts in interplanetary exploration, scientists have developed an abundance of methods to assess the inhabitability of celestial bodies. However, to our understanding, there is yet to be any way to remotely test seismic activities—one must conduct these tests on the surface of these planetary bodies.
Our CanSat converts the seismograph measurements to the Shindo scale and determine the magnitude of the tremors and accomplishes the following:
- Maintain structural and functional integrity while under the forces of launch/freefall.
- Collect air temperature and pressure data during freefall.
- Measure and record vibrations and tremors upon landing.
- Maintain a stable radio connection during freefall and landing over which experimental data may be transmitted.
- Receive accurate and precise data.
The CanSat is built around the Arduino NANO V3. Etching and soldering our own circuit boards, these are the components used:
- MPU6050 gyro
- BN220 GPS sensor
- BMP180 barometric sensor
- RYLR896 LoRa radio transmitter/receiver
(left to right) circuit diagram, PCB schematic, etched and drilled circuit
A diagram showing how the CanSat fits together
Due to the size constraints of the CanSat, the accuracy of the seismometer was achieved through software rather than hardware, relying on an MPU6050 Arduino module. This gyro converts physical movements from seismic activity into electrical signals through the analog inputs of the arduino. The entire process of parsing this data has already been studied extensively by the Japanese Meteorological Agency (JMA) and has been further developed to meet the needs of our CanSat. Our process is as follows:
- Get the X, Y, and Z angles and calculate the X-, Y-, and Z-components of measured acceleration
- Take multiple measurements in a short span of time (in our case 12 measurements every 0.12 seconds)
- Apply a Fourier transform to the 12-item datasets for the two horizontal (X and Y) and single vertical (Z) acceleration components, separating each acceleration into multiple trigonometric functions
An example of a Fourier transform of seismometer data from the 2000 Earthquake in Tottori, Japan
(left) pre-Fourier transform, (right) post-Fourier transform
- Multiply these trigonometric functions by constants calculated by the JMA to “smooth” out the data, reducing instrumental noise
(blue) high-cut filter removing high noise, (red) low-cut filter removing low noise, (black) data, (green) filtered data
- Perform the inverse Fourier transform that was applied in step 3 to merge the trigonometric functions back into the respective X-, Y-, and Z-components
- Synthesize these three components into a single vector
The composite of the acceleration calculated by the seismometer after compiling all filtered data
- Convert measurements into the Shindo scale using formula
Intensity = 2 log a + 0.94where a is the acceleration of the synthesized vector in gals (1 cm/s^2)
Unfortunately, the rocket in which TurkeyBurkey was launched in experienced unexpected results—the motor burnt through and prematurely released the CanSat, damaging our CanSat beyond repair
(left to right) rocket burning out mid-launch, post-mortem CanSat 😔
Due to the rapid unplanned disassembly of the CanSat, team TurkeyBurkey was only able to grab readings while on land and during initial launch (before the burnout of the motor). However, we were able to gather some interesting information nonetheless
The smaller peak likely comes from walking the CanSat to the launch site, while the larger peak comes from the moment of launch
The pressure remains relatively constant until the sudden launch of the rocket, in which the pressure quickly decreases. The earlier dip could be from fitting the satellite into the rocket
Temperature slowly decreases while in the rocket as it is moved out of the sunlight
Two peaks: when the CanSat is walked to the launch site, and when it is launched by the rocket.
While stationary, the seismometer records a 2 on the Shindo scale, which is roughly expected given the noise of our instruments (despite our best efforts at mitigating this with Fourier transforms). Additionally, the seismometer was tuned to record smaller measurements as we did not expect any actual earthquakes to occur and thus, the larger readings may not be as accurate.
Even with the tragic demise of our CanSat, team TurkeyBurkey still managed to snatch the dub for the "Science Mission Award." This award was given based off the scientific research and soundness of the secondary mission.
The award and the team 😊
For some reason, if you wish to embark on a journey to build this TurkeyBurkey CanSat, you should probably download these libraries:
- BMP180 library by Adafruit
- BusIO library by Adafruit
- Filters library by JohnHub
- Light MPU6050 library by rfetick
- TinyGPS library by mikalhart
After installing all libraries, connect the CanSat to a ground station. Connect the ground station to a computer and run python3 script.py to append information to a .txt file in realtime. Next, run python3 assign.py to transcibe text information into an Excel spreadsheet. Finally, run python3 grapher.py to create a mtaplotlib graph of the data.