Simple Aurora Monitor (SAM) Description and Specifications - 3-Axis SAM-III
The Simple Aurora Monitor (SAM) magnetometer system is a sophisticated semi-professional geomagnetometer designed by Dirk Langenbach (hardware) and Karsten Hansky (software). In the description below, "SAM" refers to both the original 2-axis SAM and the newer 3-axis SAM-III. Where only "SAM-III" appears, it refers to the 3-axis SAM-III.
The original 2-axis SAM Kit is not longer available, but it is compatible with the 3-axis SAM Kit. If you own a 2-axis SAM, it may be converted to 3-axis operation by adding a small daughterboard and making some wiring changes to the SAM PCB and, of course, adding a third sensor. For additional information on the SAM-II-X Conversion Kit, click here.
The primary application of the SAM-III is in the sensing and study of geomagnetism, but it is possible to use the SAM-III in other applications requiring magnetic sensing. The correspondences between geomagnetic storms, solar events and solar wind, aurora and radio propagation anomalies are well-known. The SAM-III will be a useful instrument to radio astronomers, radio amateurs, aurora photographers and experimenters. Click here to see examples of SAM data collected at the Reeve Observatory.
Click here to download
Geomagnetometry for Amateur
Radio Astronomers, an article that includes a
brief tutorial on geomagnetism as well
as a description of the Simple Aurora Monitor used in our observatory. For a
more comprehensive
Geomagnetism Tutorial click here.
The SAM originally formed the basis for a European magnetometer network. We are expanding the SAM's presence to a worldwide amateur geomagnetometer network. Our goal is to deploy the SAM on every continent. The southern hemisphere is under-represented even in professional geomagnetometer chains and networks, so we are particularly interested in deploying the SAM in southern latitudes. To become a member of the SAM network, internet access is required.
Click here for SAM-III ordering information
The basis for the SAM-III is a fluxgate magnetometer sensor manufactured by Speake & Co Llanfapley. The sensor signals are processed by a Microchip PIC16F877 microcontroller operating at 16 MHz and associated logic circuitry.
Sensor outputs, K-index and time and date are shown on a liquid crystal display. Additional interface circuitry provides serial data, analog signal outputs and alarm outputs for external processing and display on a PC or voltmeter. The processor can be set to provide a dry contact alarm relay closure when the K-index exceeds a predetermined value. The alarm function is useful to aurora photographers and radio amateurs because it could indicate aurora picture and radio propagation opportunities.
The SAM-III may be operated in an autonomous (standalone) mode or it may be used with a PC for logging and viewing.
The basic specifications for the SAM-III magnetometer system are
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Magnetic induction range: Approximately ± 50000 nT
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Resolution: 1 – 2 nT
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Connection of 1, 2 or 3 magnetometer sensors
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Microprocessor controlled, 16 MHz clock
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Data displayed on backlit 4x20 LCD
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Data transmitted over EIA-232 serial interface as ASCII text to a logging PC
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Software setup and measurement logging via EIA-232 serial-interface
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Analog measurements available on one analog output (adjustable 0 to +5 V or -2.5 to +2.5 V)
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Real-time clock with battery backup
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Isolated Form A relay output for K-index alarm
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Isolated input for detection of external voltage condition
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Power requirements: 12 Vdc at approximately 100 - 130 mA
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Temperature sensing capability (temperature is not displayed on LCD but is included in data stream)
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Software setup and data logging and viewing
SAM Frequently Asked Questions - SAMFAQ
The setup software used with the SAM-III allows the user to adjust the SAM-III onboard parameters for standalone operation.
When the SAM-III is connected to a PC running the included logging and viewing software, the software collects data from the SAM-III and provides additional downstream processing and archiving of magnetometer data. The software also produces a graphics file that may be viewed locally by any graphics viewing program or transmitted by File Transfer Protocol (FTP) to a web server for viewing on the internet.
Logging and viewing software
screenshot. The dark blue line is previous day data and the
red line is current day data. This particular graph shows a geomagnetic storm
that occurred
on July 22, 2009 (red line) starting at approximately 0300 UTC and resulted in
very good
aurora farther south than normal.
Click on the image to go to
real time data from our
Anchorage observatory.
Click here to download the SAM construction manual revision 2.3 (SAM-III manual available soon)
Click here to download the SAM software setup guide revision 1.6 (SAM-III manual available soon)
The SAM-III consists of a main controller printed circuit board (PCB), keyboard PCB and Liquid Crystal Display (LCD) module, one or two magnetometer sensors and external 12 V dc power supply. The controller PCB for the original SAM is shown below.
Although the SAM-III includes viewing and logging software specifically designed for it, it can be used with other logging methods. When in standalone mode (not connected to a PC), SAM-III only displays the real time data and does not remember it. If a user needs to log data but does not wish to have SAM-III connected to a PC, the analog outputs can be connected to an external datalogger.
The analog output can be adjusted for a range of 0 to +5 V or -2.5 to +2.5 V, so any datalogger compatible with these ranges should work with SAM-III. The datalogger software or common spreadsheet programs then can be used to chart, analyze and display the data. Data loggers are available that store the data on a SD memory card (for example, MPL-1000 and Elektor Datalogger deLuxe). We can supply the MPL-1000.
Additional applications software available for the SAM-III are
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SAM_STAT.exe – Statistics program that provides charts similar to the Bartels Diagrams
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SAM_BROWSER.exe – Browser program that provides display of archived SAM data files
Because of the magnetometer sensor sensitivity, it normally is installed at a remote location away from man-made magnetic disturbances; we are aware of sensor installations greater than 60 m from the SAM-III processor. We can provide information for locating the sensor at greater distances.
Some users have written custom
application programs that use the EIA-232 serial port to collect data for
analysis and display but that software is not available from us.
The software we supply with the SAM-III is compatible with Microsoft Windows
2000 or later.
Two Yahoo Groups have been established for users to discuss SAM applications, one in English (called SAM-INTL) and one in German (called Magmeter).
Click here for real time display of the SAM running in our Anchorage observatory
Click here for SAM-III ordering
information
We occasionally write reports of geomagnetic activity in which we compare our own observations with observations from the GOES (Geostationary Operational Environmental Satellites), Alaska Magnetometer Chain and other observatories. These reports may be downloaded by clicking here.