Originally posted by DeepThought
I thought he could add a spike where he put on the playdough. Then shine a light from behind it and mark the point of the shadow, assuming it's about half a metre away from the gyro then the distance the point of the shadow will move is of the order of 10 mm and easy to detect. Measuring the distance the point of the shadow moves and doing a little trigonometry will be a lot more precise than his protractor set up.
The best way is to use a powered gyro and let it run for hours, 6 hours would change the orientation by 90 degrees and 24 hours, 360 degrees. It would match the foucault pendulum experiment. And of course, eliminating Earth field isolates the motor windings and such.
So I imagine a setup where you have two motors, one on each end of the gyro shaft, each one with solar panels around the perifery of the motor case and all that surrounded by helmholtz coils to eliminate Earth field and have some high powered lights, maybe efficient LED's aimed from above so no matter the changing position, the light always hits the solar arrays and thus will run as long as the light source is on. You could do a year of run 24/7 if the mechanics were high enough quality.
So let's built one🙂
Here is one using laser interferometry, a Sagnac interferometer to detect Earth spin:
https://s28.postimg.org/x44vfak99/DSCN0644.jpg
Here is the one using play station controller with helmholtz coils to eliminate or greatly reduce Earth field.
YouTube