old_contents: from pint import UnitRegistry
  from utils import config_file_path
  
  
  # Instantiate a common units registry
  UR = UnitRegistry(autoconvert_offset_to_baseunit=True)
  UR.load_definitions(config_file_path('pint.txt'))
  
  
  # Specify order and name of data columns
  DATA_SPEC = (
      'date',
      'temperature_C',
      'pH',
      'water_tank_L',
      'nutrients_mL'
  )
  
  PH_CONFIG = {
      'adc': {
          'i2c_busn': 1,
          'i2c_addr': 0x4F,
          'v_ref': 2.5 * UR.V,
          'v_off': 1.251 * UR.V,
      },
      'calibration': {
          'temperature': 21.2 * UR.degC,
          'points': (
              {'ph': 4.0 * UR.pH, 'v': 1.418 * UR.V},
              {'ph': 7.0 * UR.pH, 'v': 1.224 * UR.V}
          )
      }
  }
  
  WATER_TANK_CONFIG = {
  }
  
  PUMP_CONFIG = {
      'gpio_sleep': 17,
      'gpio_step': 27,
      'wake_up_time': 1 * UR.ms,
      'max_frequency': 3 * UR.Hz,
      'step_angle': 1.8 * UR.deg,
      'steps_per_volume': 1050 / UR.mL,
      'microsteps': 8
  }
  
  CONTROLLER_CONFIG = {
      'nutrients_concentration_per_ph': 1.65 * UR.mL / UR.L / UR.pH,
      'min_pumped_nutrients': 1 * UR.mL,
      'desired_ph': 6.0 * UR.pH,
      'solution_volume': 50 * UR.L,
      'proportional_k': 0.5,
      'iteration_period': 5 * UR.min
  }
  
new_contents: from pint import UnitRegistry
  from utils import config_file_path
  
  
  # Instantiate a common units registry
  UR = UnitRegistry(autoconvert_offset_to_baseunit=True)
  UR.load_definitions(config_file_path('pint.txt'))
  
  
  # Specify order and name of data columns
  DATA_SPEC = (
      'date',
      'temperature_C',
      'pH',
      'water_tank_L',
      'nutrients_mL'
  )
  
  PH_CONFIG = {
      'adc': {
          'i2c_busn': 1,
          'i2c_addr': 0x4F,
          'v_ref': 2.5 * UR.V,
          'v_off': 1.251 * UR.V,
      },
      'calibration': {
          'temperature': 21.2 * UR.degC,
          'points': (
              {'ph': 4.0 * UR.pH, 'v': 1.418 * UR.V},
              {'ph': 7.0 * UR.pH, 'v': 1.224 * UR.V}
          )
      }
  }
  
  WATER_TANK_CONFIG = {
  }
  
  PUMP_CONFIG = {
      'gpio_sleep': 17,
      'gpio_step': 27,
      'wake_up_time': 1 * UR.ms,
      'max_frequency': 1 * UR.Hz,
      'step_angle': 1.8 * UR.deg,
      'steps_per_volume': 1050 / UR.mL,
      'microsteps': 16
  }
  
  CONTROLLER_CONFIG = {
      'nutrients_concentration_per_ph': 1.65 * UR.mL / UR.L / UR.pH,
      'min_pumped_nutrients': 1 * UR.mL,
      'desired_ph': 6.0 * UR.pH,
      'solution_volume': 50 * UR.L,
      'proportional_k': 0.5,
      'iteration_period': 5 * UR.min
  }
  
subject: change pump microstepping