Compass Magnetometer Project
The Sun with its immense energy stores and close proximity to Earth is a great celestial object to monitor at all wavelengths. What's more, one can monitor activity on the Sun via indirect means. More precisely, it is possible to detect solar activity by monitoring the Earths magnetic field. It's also possible to detect solar activity such as solar flares by monitoring Very Low Frequency (VLF) signal paths which use the Ionosphere as a means of propagation. Check out my SID receiver page.
Coronal Mass Ejection
I wanted to build a device which I could use to monitor geomagnetic storms from my location. I initially built a simple magnetometer consisting of some magnets suspended by a thread (details found here). After a short time though, I noticed that I needed something better if I was to do extensive recordings. I did some searching online and came across a compass magnetometer design that caught my attention.
The schematic depicted below is from AuroraWatch and is the one I decided to build. I wound the coil that can be seen at the bottom of the schematic diagram myself as opposed to ordering the part from an online source. All of the other parts I acquired from Radio Shack or Wal-Mart. I used a bread board to build the initial circuit and mounted the compass and coil on the same bread board as well.
Click on the schematic for more details from AuroraWatch.
I have included a picture of the completed magnetometer and the power supply. I used a kit box to enclose the components and keep ambient light out of the light gate. I used a small 200 ohm reed relay coil for the electromagnet. I have placed a North arrow in the image to allow for a better idea of where the components should go.
The following image is the finished dual polarity power supply that is required to power the Op741. The IR LED is very current hungry so I had to use a 1.2 amp transformer to provide adequate power to the circuit.
The recording device is a Radio Shack RS 22-812 multimeter or a DI-194RS. The multimeter is capable of connecting to a computer with the use of a serial cable. This is ideal for prolonged unattended recordings, and a feature which I used to it's fullest.
The compass magnetometer is surprisingly sensitive, capable of detecting a human body at a distance of around three meters. Thunderstorms tend to cause the magnetometer to behave very erratically. Furthermore, during geomagnetic storms the meter readings are all over the place. The following two images show an example of a solar event being detected by a magnetometer. The first image is from the HAARP Fluxgate Magnetometer in Gakona Alaska for August 30, 2006. The second image is from my homemade compass magnetometer for roughly the same time period. As can be seen from the images, the small solar event which took place at around 5:00 a.m. local time was recorded by both magnetometers.
I enjoy these sorts of projects because they make me more aware of my surroundings, and how everything is interconnected in some way or another. I hope the information here might intrigue someone out there enough to give this little project a try.
Good luck!
