MagnetometerDIY geomagnetic storm monitoring | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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I picked a PCV cross-joint to hold the laser/sensor assembly. While a straight piece of pipe would work too, the side openings allow me to adjust the magnetometer by peeking inside and seeing where the reflected laser spot is. The laser and the sensors are attached to the opposite sides of a small PCB:   When the assembly is inserted into the cross-joint the spring pushes against the side of the pipe to hold the assembly firmly in place. Four screws press at the bottom of the laser to allow precise pointing.    In order to get smooth transition of the signal corresponding to the movement of the spot of reflected light, I made a diffusor screen from a piece of thin plastic:   After attaching the horizontal pipe that connects the laser/sensor assembly to the mirror cell, the laser has to be aligned. Attaching a piece of scotch tape makes the laser beam visible and by adjusting the supporting screws laser can be accurately centered:  Here is the completed magnetometer, assembled and ready for testing:   It worked from the first time! I'm kidding, of course. It didn't work from the first time. Getting it to work took me a couple of weeks during which a large area of the kitchen was declared off-limits for unauthorized personnel and strict rules against carrying anything ferromagnetic (spoons, scissors, etc.) were strictly enforced. During those few weeks I somehow managed not to get kicked on the street by my wife, which speaks volumes about her endless patience. Thanks! Anyway, after all remaining issues were resolved, to everybody's great relief the magnetometer got installed in it's permanent place - in the patio garden, hidden well out of sight. Can you find it on the picture below?  It's laying safe and snug on a couple of bricks under the gray box held in place by a pot with a red flower (the same flower that I was faithfully watering for several months before somebody decided it's not funny anymore and told me it's a fake one made of plastic). A long cable is running underground to the amplifier and data logger, located in the house. |
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