Should have been easy.  The start/spin up turned out to be difficult due to an unexpected reason.

I programmed the spin down to be due to the inertia of the platter by simply disabling the driver, thus letting the platter spin down naturally.  Subsequent start ups were, interesting.

Sometimes the platter would jerk backwards, or forwards when the next person pressed the start button.  After much thinking I realised that at the moment the driver is enabled it re-enables the last known voltages to the motor.  In the meantime, of course the motor has moved, thus causing the motor to jerk from it's current random position to the one on consistent with the signal it's now getting, usually rapidly and jerking the platter, sometimes in the opposite of the desired rotation direction.  The next progremmed step, being in intent, the first of a smooth acceleration curve, is then of course frutrated by an already, sometimes contrary,  moving platter.  The result being that a significant amount of start ups did not accelerate as designed resulting in a stalled platter and a dissatisfied user.  Sadness ensues.

The solution was to set the motor into the last known step, after inertial spin down, in readyness for the next start signal by brielfly enabling the driver after spin down.  No more jerking on startup.

Why a stepper driven zoetrope I here you ask?  I will answer the why laler.

Last changed: 13. November, 2020 at 18:50

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