Stepper

[SVHM]

I would like to know if Pypilot can control a stepper motor?

I would like to connect a motor directly to the head of the self-steering windvane.  The head will rotate only about 30 degrees each direction so I am thinking a brushed motor might not be able to increment in that small amount. Or am I wrong about that?

Would adding a pwm control accomplish the same thing?  How about setting the gains way down instead?  With the paddle removed from the vane there would be very little resistance.

[seandepagnier]

The best way to do this with pypilot currently would be to gear down a brushed motor sufficiently. My actuator moves my main rudder by 30 degrees per second, so if you geared it similarly so that 1-2 seconds moves the full range it should work as well. The motor required to do this could be very small. There are linear actuators available which move very slowly 10-20mm/s and you could probably rig this up to work.

Stepper motors generally consume more power, unless they are closed-loop. They are great for accuracy but in an autopilot there are constantly errors that are being compensated for, so absolute accuracy is not required, at least not for a boat that can steer well using a wind vane.