1. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
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    28 Dec '04
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    53223
    15 Dec '16 12:35
    Originally posted by twhitehead
    The moment you introduce a motor, you have magnetic fields interacting with earths magnetic field interfering with the whole experiment.
    I saw one experiment that had some kind of directional gyro from some video game controller and they used helmholtz coils to eliminate the interference of Earth's magnetic field. The proved it by using a compass pointing north with the power to the coils turned off then turning the coils on countering the Earth field, the compass would spin wherever you aimed it and ignored Earth field. So that can be dealt with.
  2. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
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    53223
    15 Dec '16 12:374 edits
    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
  3. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
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    53223
    15 Dec '16 17:08
    I just realized the solar cells don't have to rotate, they can be attached to the motor case which doesn't spin. Somehow I envisioned the solar cells attached to the rotors and spinning, not likely, eh. So the question then is how much energy does it take to make a gyro rotor with good bearings to rotate at whatever it needs, 10K RPM? 20? Whatever.
    Can we get away with say, ten watts? At 1300 odd watts per square meter on top of the atmosphere, counting 25% cells, if each motor can run on ten watts, it would take roughly 125 Cm^2 or in dumb talk, 7 by 7 inches on each one. That assumes one sun worth of light on the cells. So it would have two sets of cells about the size of a ping pong racket glued to the top of the motor frame which would of course be a lot smaller but there wouldn't be much load, my guess is the cells would mass 20 grams or so, one set on each motor, which would be recieving 20 watts of torque and able to spin up to 10K RPM or so. That would be a 21st century version that wouldn't poop out in 5 or 10 minutes.

    That would clearly show the precession in an exact 24 hour daily routine.
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