Johnny-five: Add support for Adafruit DRV8871

[TheBekker]

I would love to see support for these simple but powerful motor drivers.

I can drive them right now, but its a bit hacky, since i need to initialize 2 motors for each direction, since this doesnt use a direction pin, but instead use 2 pwm inputs, one for each direction.

https://www.adafruit.com/product/3190

[dtex]

Johnny-Five can support this motor driver. Try a configuration like this:

js // substitute your pin numbers of course motor = new five.Motor({ pins: { pwm: 3, dir: 12 }, invertPWM: true });
It doesn't matter which motor input pin is pwm and which one is dir.

Let me know if this works for you and we can add an alias in Motor.SHIELD_CONFIGS for this model number for future genreations.

[TheBekker]

Seems to almost work, but not matter if i use .start() or .reverse() it runs i the same direction.

[dtex]

That sounds like the PWM value isn't being inverted when the direction changes.

Make sure the invertPWM: true bit is there and try .forward() and .reverse() instead of .start(). That last one just resumes the most recent "on" state regardless of direction.

[dtex]

Oh wait, my last comment was in response to a comment that is no longer here...

The part about forward and reverse still hold true though

[TheBekker]

Ahh seems like it was .,start() that was the issue, works perfect with forward and reverse.
Thanks a lot, that shaved of some code! :)

[dtex]

I'm going to re-open as a reminder to add an example for the DRV-8871