oscaralexander
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Location: Amsterdam, NL
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"UFO Radar" with magnetometer

Thu Jan 10, 2019 8:17 am

Hi gang! I'm new here and excited to dive head-first into this beautiful stuff.

I'm the co-founder of the Dutch UFO Reporting Center (good for around 75 reports a month) and was recently made aware of the MADAR project: a little device that measures fluctuations in the (electro)magnetic field as well as compass deviations. I should probably add that historically a lot of significant close encounters involved EM disturbances (e.g. cars shutting down, and electronic instruments malfuctioning).

Being a designer and developer myself, this seemed like a really nice device to copy to get my hands dirty with Python and the Raspberry Pi platform. I also have a UFO witness in the rural north of the Netherlands who repeatedly has weird UFO experiences and would love to deploy such a device.

On to my reason for posting here.

Going by the statuses output by the MADAR nodes across the US (i.e. the data in the pop-ups), I see that it registers:

  • Compass in degrees (I assume degrees from magnetic north?)
  • Field in milligauss
  • Average ambient in milligauss
  • Standard deviation in milligauss
When the Field value exceeds a predefined trigger value (40 by default) it sets the device into Alert status. My question would be: would a Sense Hat suffice to measure these values with sufficient accuracy, or would I need a more sophisticated magnetometer / compass? Recommendations very much welcome.

The rest I can hopefully figure out myself :) Thanks!
Last edited by oscaralexander on Thu Jan 10, 2019 12:32 pm, edited 1 time in total.

Andyroo
Posts: 1973
Joined: Sat Jun 16, 2018 12:49 am
Location: Lincs U.K.

Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 12:10 pm

Now then folk - never knock a persons belief as they may be correct.

As for the OPs question - I’m not sure of the tech but the details of the hat can be found at https://thepihut.com/products/raspberry ... t-astro-pi
Need Pi spray - these things are breeding in my house...

Idahowalker
Posts: 445
Joined: Wed Jan 03, 2018 5:43 pm

Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 12:23 pm

I have a MPU9250 that comes with a magnetometer but your most likely looking for a 3 axis Fluxgate magnetometer.
Without knowing why you are deleting my postings, I will not know how...

oscaralexander
Posts: 4
Joined: Thu Jan 10, 2019 7:46 am
Location: Amsterdam, NL
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Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 12:27 pm

Andyroo wrote:
Thu Jan 10, 2019 12:10 pm
Now then folk - never knock a persons belief as they may be correct.

These are hardly beliefs. Mind you, UFOs are not synonymous to alien spacecraft. We don't know what they are (nor does the Pentagon after spending $22 million looking for an answer, for that matter), but we do know there are quite a few incidents where UFOs affected the electromagnetic field.

I've seen the Sense Hat specs but not sure if there are magnetometers out there that are better fit for this particular job. I feel the Sense Hat might be nice in the sense a Swiss Army knife is nice, but if you need scissors, you're better of buying a pair of scissors. Feel me?

In any case, thanks for providing the first relevant answer :)

oscaralexander
Posts: 4
Joined: Thu Jan 10, 2019 7:46 am
Location: Amsterdam, NL
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Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 12:32 pm

Idahowalker wrote:
Thu Jan 10, 2019 12:23 pm
I have a MPU9250 that comes with a magnetometer but your most likely looking for a 3 axis Fluxgate magnetometer.

Thanks! Can you explain in layman's terms how a 3-axis fluxgate magnetometer is different from what the Sense Hat is equipped with?

Andyroo
Posts: 1973
Joined: Sat Jun 16, 2018 12:49 am
Location: Lincs U.K.

Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 12:40 pm

Given that the USAF spend $1,280 per cup the money spent on hunting things the money may have just set the office up and paid for the stones to be painted white.

This sounded interesting but I’m not sure it’s sensitive enough https://forum.arduino.cc/index.php?topic=229281.0

The closest I can find is http://pyfn.com/PDF/electronics_pdfs/ma ... roject.pdf as it detects changes throughout the year.

Apologies UFO = alien is a bad habit I have. Good luck hunting.
Last edited by Andyroo on Thu Jan 10, 2019 12:51 pm, edited 1 time in total.
Need Pi spray - these things are breeding in my house...

Idahowalker
Posts: 445
Joined: Wed Jan 03, 2018 5:43 pm

Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 12:51 pm

oscaralexander wrote:
Thu Jan 10, 2019 12:32 pm
Idahowalker wrote:
Thu Jan 10, 2019 12:23 pm
I have a MPU9250 that comes with a magnetometer but your most likely looking for a 3 axis Fluxgate magnetometer.

Thanks! Can you explain in layman's terms how a 3-axis fluxgate magnetometer is different from what the Sense Hat is equipped with?
Sensitivity.

The least sensitive device would be a hall effect device.

The next sensitive device would be a magnetometer, such as what is in a MMU. Whiles the sensitivity of a MMU can be increased, there will be limitations.

Then we come to the 3-axis fluxgate magnetometer, which is just a more sensitive device. You can see more sensitive 3-axis fluxgate magnetometer on satellites that have a magnetometer to measure the magnetic fields of planets and moons. With 3 axis one will get direction and they can be used as a navigational aid.
Without knowing why you are deleting my postings, I will not know how...

oscaralexander
Posts: 4
Joined: Thu Jan 10, 2019 7:46 am
Location: Amsterdam, NL
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Re: "UFO Radar" with magnetometer

Thu Jan 10, 2019 1:00 pm

Thank you very much for clarifying.

In my google searches prior to this topic I came across several 2 and 3 axis magnetic sensors (these, specifically). From your comment I understand that the Sense Hat is either a single or 2 axis sensor and therefore lacking in sensitivity for this purpose?

I'll gladly continue my search with the info you provided, but perhaps you can tell me if the sensor explicitly needs to be of a "fluxgate" type? (I have no idea what that means, tbh.)

Thanks again!

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