Driving a specific distance

For driving a specific distance, we use the PI controller again and incorporate the distance measurements into our encoder object. We calculate how many ticks we want the left wheel to have turned for a given distance, and then use this instead of a timeout component.

Refactoring unit conversions into the EncoderCounter class

We want the conversions for our encoders in the EncoderCounter class to use them in these behaviors. Refactoring is the process of moving code or improving code while retaining its functionality. In this case, converting distances is one of the purposes of using encoders, so it makes sense to move this code in there:

1. Open up your encoder_counter.py class. First, we need the math import:

   from gpiozero import DigitalInputDevice
   import math
   ...

2. At the top of the class, add ticks_to_mm_const as a class variable (not an instance variable) to use it without any instances of the class. Set this to none initially so that we...