• Write the software.

The software needs to do a few things:

• Connect to my MQTT server for control purposes,
  • Receive new patterns,
  • Trigger patterns.
• Do the kinematic calculations,
• Drive the stepper motors.

I'm concerned that handling network traffic might interfere with smooth operation of the stepper motors, so I think I might unsubscribe from time-consuming MQTT topics while a pattern is playing, and then subscribe again once a pattern is finished to get new patterns from persisted topic publications.

• Build the electronics.