I had one GPIO pin unused (on the 26-pin version of the pi B), so I used this to route a signal to the ¬Enable pin of the drivers. I altered the code to wake the driver, enable the output, step the required number of times, disable the output and sleep the driver.
2-phase (bipolar) stepper motor showing very fine cogs
This ensures that the motors are de-energised before the logic sleeps, and it does definitely reduce the number of phantom pulses. I can run the dials back and forth hundreds of times without losing place. However, the large ‘weather’ hand sometimes appears to stumble. This could be due to dirt on the cogs, as the teeth are extremely fine, as can be seen in the photo. The motor is about 25 mm (one inch) across.
But also, I need to sort out why the voltage on one of the coils seems lower. Is there a problem?