Opensource Aurora Monitor for Schools & Home
This incarnation is being tested at my workplace, a Sixth Form College in the North of England. A precision power supply has been built by Rebecca & George two first year A-level science & geology students. The system has been networked, thanks to Mark Ayres-Rousson and Lee West for networking help.
I have demonstrated this and other projects at the Maker Faire, Newcastle in 2016 and 2017
As the solar wind interacts with the upper atmosphere it distorts the earth weak magnetic field. Thus monitoring variations in the earth's field via a buried magnetometer perversely gives information on the strength of the solar wind and coronal mass ejections from the sun. During periods of high activity aurora may be visible.
This is the working initial version of a simple though sensitive earth field magnetometer at a total cost of ~£60 giving a resolution of a few nT compared to a typical earth field of 50,000 nT at the present location.
A its core is a Speake Sensors FGM-3h fluxgate magnetometer (~£20) in a thermos flask. A simple signal cable connects to an Arduino Uno which monitors the ~50kHz square wave signal from the F.G.M as well as a temperature sensor. Data are transferred via USB to a headless networked Raspberry Pi which averages the frequency over 1 minute appending the timestamped results to a datafile. Data is plotted every few minutes using matplotlib and these plots of the daily field variation are uploaded to a website every 5 minutes. along with the raw data. The python script is robust enough to handle signal and power outages. As the FGM is sensitive to temperature the system incorporates a temperature probe close the FGM to allow for further tweaking of the resolution. The data is stored in .mseed format, a geophysics standard permitting further analysis using tools such as ObsPy
The results look good. One may compare the plot above with that produced by the British Geological Survey using rather more expensive equipment - see B.G.S. Their nearest station is the middle set of plots - the yellow line being the E-W component measured here.
The project is simple to complete in its current form. The code is pre-written, easily modified and being Python can run on Windows, Linux, Mac or on a device such as a Raspberry Pi without modification. Being modular one can easily extend or adapt the code or hardware allowing for ongoing development at home or by a school science club.
Further development could include:-
- Replacing the Arduino with a Pi/Beagleboard fitted with a fast digital frquency sampler.
- Adding a wireless interface.
- Adding one or two more sensors to monitor vertical and N-S components of the earths field
- Having the code email/flag abrupt changes likely to indicate aurora.
- Replacing the Arduino with a PIC or similar.
- Performing more sophisticated signal processing, possibly using ObsPy.
Please email me for copies of the code and construction details.
I am interested in promoting real-science projects in schools and the community. As an A-level physics teacher I have some years experience in project development with students both in my college and local schools. The experience gained by students is invaluable and makes a tremendous addition to a university or apprenticeship application. I want to promote geophysics projects more heavily via projects to monitor aurora, lightning and infra-sound.
Along with the fluxgate monitor here I am presently building a proton precession magnetometer and gradiometer for geomagnetic surveys. I also have a working infrasound monitor which is looking very interesting indeed (see Blog).