new idea (is it old?)
place two single axis accelerometers on a board with the axis aligning, connect the output to a ADC with the negative reference connected to the "negative" accelerometer (the one with the lower voltage direction pointing outwards)
if the gyro is sloped, since both accelerometers experience the same static acceleration, the ADC reads 0, but, if the entire gyro is spinning, then one accelerometer should be more + than normal, and the other will be more - than normal, and the ADC will be able to output the speed of the spinning! and since gravity affects both equally, tilting the gyro should not affect the readout. add another ADC to determine the timing of each revolution by looking for the max and min of the sine wave one of the accelerometers will create during the spin (only if it is spinning vertically, but any wobble should register (the ADCs from microchip are 20 bit)).
too bad you won't be able to determine the direction, any ways around that? another perpendicular accelerometer and a MCU to calculate?
