Lightning Detection and Triggering for the TARA Experiment

Names: Bennett Haase-Divine, Lawrence Freestate High School
Pierce Giffin, Shawnee Mission East High School
Research Teacher Mentor: James Deane, Ottawa High School, Ottawa, KS
Research Mentor: Prof. Dave Besson, University of Kansas, Lawrence, KS

Purpose: The purpose of our project was to accurately detect flashes of lightning as well as determining their approximate position and time of strike so that other devices involved in the TARA project can study and collect data from flashes of lightning while they’re still striking.

Methods: For light detection, we used several photoresistors and an arduino board that read the voltage off of each resistor. If the voltage was high enough, the program would identify it as a lightning strike. As soon as a flash of lightning is detected, a signal is sent out to alert other devices that lightning has struck. To calculate the angle the strike occurred relative to the device, we see how high the voltages are on each photoresistor relative to one another and weight each  voltage with the photoresistor’s assigned angle. After a flash of lightning is detected, a microphone starts listening to the environment for the thunder. Once it picks up a loud sound, it calculates how far away the strike of lightning occurred. After all the data is collected, it is stored on a micro SD card inside of the device.

Results: Almost all of the necessary operations work properly with a simulated strobe machine. The device is capable of detecting nearly 100% of simulated flashes and calculating the correct angle within about 10%. The signal is capable of being sent out to other devices within 5 milliseconds. The device can accurately identify two flashes of lightning within 20 milliseconds of each other. Since a single lightning strike flashes once then flashes again about 30 milliseconds later (and can repeat several more times), the device is capable of detecting a strike of lightning on the first flash then sending out a signal to other devices to collect data on other flashes. The sound device works accurately. We are able to calculate the distance within 10 meters. Without simulating with actual lightning, it is unsure as to how far away a lightning strike could occur without being detected by the device. All of the data is able to be stored on a micro SD card. However, problems arose with opening multiple files; therefore, all the data must be stored on a single file.

Meaning to Larger Project: This detector and the directional and ranging data it provides will permit better triggering and data collection for portions of the TARA experiment. http://www.telescopearray.org/tara/

Future Research: The lightning detection device is nearly ready to be implemented. The device still needs to be field tested and, if possible, store the data on multiple files. If quicker and more precise measurements are needed, this project could be redesigned using a time-to-digital converter instead of the Arduino Uno currently being used. However, a new code would have to be implemented.

Acknowledgements:

We appreciate the assistance and guidance of the following students during this project.

• Steven Prochyra, University of Kansas

• Samantha Conrad, University of Kansas