Simple Aurora Magnetometer (SAM)

(2024-05-26) PE1ITR
Since the year 2004 I still have an online magnometer operational. In 2018 I had a computer crash that left the magnetometer off. But recently I picked up the thread again and the magnetometer is back online. This time the software is made with Python scripts and runs on a small Odroid N2 Linux computer. In addition to the magnetogram, two temperature sensors have been added. One sensor is placed in a hole in the stone where the fluxgate sensors are located, and the other temperature sensor is positioned just outside the Styrofoam box. A daily temperature trend chart is also available online.

==== The magnetometer graph can be viewed here. ====

This page shows photos of the setup. There are also links to the archive. If the k-index indicates 6 or higher between 12 and 22 UTC, a notification will be given on the Telegram group vhf_dxalerts.

There are many more of these magnetometers online and you can see them on the magnetometer grid website.

Old pictures

Below are two photos taken in April 2004. The box with the magnetometer sensor is still the same, but it is now in a different location.

Despite the large Styrofoam box, I still see temperature drift on the magnetogram when the outside temperature is changing. This is a point for improvement.
The sensor is in a small Styrofoam box filled with bird sand. This small box is again mounted in the middle of the large Styrofoam box shown in the photo.

The sensor is located in the basement 1 meter underground. In a residential environment it is very difficult not to have any disturbances in the magnetic field. A car in front of the door can already be seen with a 50 nT jump. This is automatically corrected by the software if possible.


By Sensor in styrofoam box


SAM + Computer in 2004

New pictures


Inside the box just before filling up with sand.

Links

  • Online Magnetometer Eindhoven.
  • The historical archive of SAM Eindhoven.
  • SAM Europe online grid
  • WCY A and K
  • NOAA Aurora Dashboard


    History

    2025-0-09
I have updated the chart on the website by adding a colored bar. The color is determined by the K-index.


2025-08-08
The computer has been built into an enclosure with connectors for the magnetometer and temperature sensors.
In the SAM sensor controller, the battery was replaced so that upon startup, the system resumes from the previous time.
Two things were changed in the calculation process. The moving average filter was replaced with a median filter, which now operates with a window of 36 samples (1 sample every 10 seconds).
Afterwards, a Butterworth filter with a cutoff frequency of 0.0007 Hz was applied. This results in a much smoother signal.

2024-11-03
Offline. Power supply problem.

2024-07-27
Added 2 kg shell sand around the stone just before 14 UTC. 

2024-07-19
Posted a photo of the inside box with the brick and the sensors inside. Just without the sand filling for a while.
Provisional graph with the current temperature trend placed online. 1 temperature sensor is in a hole in the stone and the other sensor is just outside the box. Let's watch this for a while.
Graph

2024-07-17
Added Bx sensor (not connected yet) and temperature sensors in de sensor box.

2024-07-07
Switched to an odroid N2 computer. 
The 20-year-old shell sand in which the sensor was located was removed. Fluxgate Sensor is now mounted in a hole in a stone. 
Preparation to add a X-axis sensor.

2024-05-25
Written new software in python + bash to readout the magnetometer.
SAM Magnetometer again online. Have te replace the onboard battery if power is lost.

2018-01-10
Computer Crash.

2004-01-01
Magnetometer online.

2003-12-20 (+/-)
Build Magnetometer



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