Homebrew Magnetometer.

So, I run a website: Aurora Forecast, or The Aurora Forecast Service . It aggregates a bunch of data and provides it is a visual format for mainly aurora hunters (Australis and Borealis). The data is pretty intense and you need to have some understanding of what you are looking at, but I think it works well.

As part of this service I have been integrating a few of my own homebrew magnetometers. It’s been a slow process, that has been developed and improved over a number of years, and it’s now getting close to be a “releasable” product.

My goal is to have other users of TAFS have their own Magnetometer to feed into TAFS, and have their data available on the graph. It means (a) I get more data for new locations, and (b) end users get to be involved in some cool gear and be involved in a cool citizen science idea.

So, I’ve finally settled on using the following:

• Arduino Wemos D1 mini.
• Wemos SD Card Shield.
• PNI MicroMag 3 Magneting sensor.
• Serverside mySQL DB with submission via GET URL.

I’m using the D1 as it has inbuilt wifi, which I had to take a while to confirm was not affecting readings, prior to the D1 I was using a UNO and an Ethernet shield. The wifi gives greater flexibility in deployment. The SD card is used for loading configuration, such as the wifi SSID, password and other options.

The Micro Mag 3 has become my preferred option as it’s cheap and can record much smaller field movements compared to other units. It uses the SPI protocol to talk to the D1. I have also tested the PNI RM3100 which uses the better I2C interface, but it is a lot more expensive and the data is no better, maybe more noisy (more testing required). The RM3100 with the I2C interface would be nice on the D1 as it uses less pins and would allow me to add other I2C devices, such as the 48x64px oLED screen so users could see the state the unit is in.

This is the first post of hopefully many. and a place holder for people to get in contact with me if they are interesting in being involved.