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Aurora-Borealis-Detector-Raspi

This personal project meant to exist because of auroras hobby came to my life. This is a manual for beginners, as i am on this science field. Feel free to correct me. Been trying to get the most accurate but according to hw used and knowledge

Neccesary items to get Aurora Detector Raspi based.

Not going to talk about raspberrypi installation.

Magnetometer installation/detection

Once we get the product at home and with the RaspBerryPi switched off, we proceed to assembly it to the GPIO. Since the Xloborg is a magnetomer specifically adapted, there is no need to adapt anything. Just plug it and bingo. This is not rocket science.

Switch raspi ON. In order to get the Xloborg magnetometer recognized by the raspi, we proceed with following commands.

  sudo mkdir ~/xloborg
  sudo cd ~/xloborg
  sudo wget http://www.piborg.org/downloads/xloborg/examples.zip
  sudo unzip examples.zip
  sudo chmod +x install.sh
  sudo ./install.sh

We wil be having created several folders/files. go into and execute it

  sudo cd ~/xloborg
  sudo ./XLoBorg.py

You will be getting:(otherwise you have done something wrong) Check this image: ex

From these values, we will be looking after mX,mY and mZ ones. Now, we have installed the magnetometer

Calibrating mangenotmeter

Basically this consists of

  • getting values from three axis given
  • and on each axis based, get the min value and the max one
  • having the difference for each one, plus to the normal value you get

Here is where patience takes place since i had neither a robot nor a automatic way to move the magentomeneter in every direction for a long period of time (5000 seconds)

I used the following script:

https://github.com/marioamas/Aurora-Borealis-Dectector-Raspi/blob/master/calibration-script.py

The script is pretty simple. In addition to it, you will have to run this as well:

for i in {1..5000}; do ./calibration-script.py >> data.csv;sleep 1;done

At sametime this script is being executed, be prepare to move the magnetometer in every direction, upside down included :P

The output would be something similar to (where first colum is X, second is Y and third is Z)

-00602, +00462, +02022
-00605, +00461, +02021
-00605, +00462, +02026
-00604, +00455, +02026

So, once we have gathered the data, we just take the max and the min using for instance, excel, python or whatever. Having those values for each column, we wil be having something like this

X Diff = (maxX + minX)/2
Y Diff = (maxY + minY)/2
X Diff = (maxZ + minZ)/2

Note that these values will be needed afterwards.

To check if the magnetometer has been properly calibrated you can use 3D Plot functions from python libs. I used this one:

https://github.com/marioamas/Aurora-Borealis-Dectector-Raspi/blob/master/plotter.py

i got something like this, not pretty accurate but close.

plot

Collecting data and sending it to Xymon Server

This script i built will do the job.

[kp]
       ENVFILE $HOBBITCLIENTHOME/etc/hobbitclient.cfg
       CMD $HOBBITCLIENTHOME/ext/ReadCompassRaw.py
       LOGFILE $HOBBITCLIENTHOME/xymon-kp.log
       INTERVAL 2m
  • Server config as well on graphs.cfg
[kp]
           TITLE kp
           YAXIS kp
           DEF:kp=kp.rrd:kp:AVERAGE
           LINE2:kp#@COLOR@:kp
           GPRINT:kp:LAST:Current\: %5.2lf%s C
           GPRINT:kp:MAX:Max\: %5.2lf%s C
           GPRINT:kp:MIN:Min\: %5.2lf%s C
           GPRINT:kp:AVERAGE:Avg\: %5.2lf%s C\n
  • on xymonserver.cfg add:
kp=ncv  => to TEST2RRD var, without deleting any other
NCV_kp="kp:GAUGE" => as a new line

Checking the info we are getting

Aside the whole info given above, you can add alerts by when the magnetic field varies more than 50 units (nano teslas i think the value is).

We have to bear in mind several factors could alter the data:

  • magnetic filed noise caused by TV blablabla
  • magnetic field noise caused by Raspberry itself
  • if not well calibrated, place the magnetometer in fixed place.
  • If you are located far from north, south pole you wont appreciate this variation. I am living in Newcastle (UK)

I got, comparing with the magnetometers located in Lancaster University, same variations at same time. http://aurorawatch.lancs.ac.uk/

Here a capture of the graph generated.

graph

Info gathered from:

http://www.camelsoftware.com/firetail/blog/uavs/3-axis-magnetometer-calibration-a-simple-technique-for-hard-soft-errors/
http://rwsarduino.blogspot.co.uk/2013/01/inertial-orientation-sensing.html
http://upload.wikimedia.org/wikipedia/commons/c/c7/WMM2010_F_MERC.pdf
https://github.com/Black-Pixel/Arduino/blob/master/magneticFieldStrength/magneticFieldStrength.ino

enjoy and distribute!!!