for review

liquid_voltage_lookup

  def self.liquid_voltage_lookup(beer_voltage, battery_voltage)

    # solve for rt in kilos: vo = vbat * (Rt/(Rt+R1))
    # vbat = battery_voltage
    # vo = beer_voltage
    # r1 = 100

    temperature = nil
    rt          = BigDecimal(beer_voltage,6) * BigDecimal(100,6) / ( BigDecimal(battery_voltage,6) - BigDecimal(beer_voltage,6) )  if battery_voltage!=beer_voltage
    if rt
      if rt >= 222.6075
        temperature = -6.0
      elsif rt <= 40.2726
        temperature = 31.0
      else
        values = nil
        values = { t: 30.0, start:  40.2726, end:  42.0331  } if rt > 40.2726
        values = { t: 29.0, start:  42.0331, end:  43.8811  } if rt > 42.0331
        values = { t: 28.0, start:  43.8811, end:  45.8214  } if rt > 43.8811
        values = { t: 27.0, start:  45.8214, end:  47.8592  } if rt > 45.8214
        values = { t: 26.0, start:  47.8592, end:  50.0000  } if rt > 47.8592
        values = { t: 25.0, start:  50.0000, end:  52.2496  } if rt > 50.000
        values = { t: 24.0, start:  52.2496, end:  54.6141  } if rt > 52.2496
        values = { t: 23.0, start:  54.6141, end:  57.1002  } if rt > 54.6141
        values = { t: 22.0, start:  57.1002, end:  59.7148  } if rt > 57.1002
        values = { t: 21.0, start:  59.7148, end:  62.4653  } if rt > 59.7148
        values = { t: 20.0, start:  62.4653, end:  65.3595  } if rt > 62.4653
        values = { t: 19.0, start:  65.3595, end:  68.4060  } if rt > 65.3595
        values = { t: 18.0, start:  68.4060, end:  71.6135  } if rt > 68.4060
        values = { t: 17.0, start:  71.6135, end:  74.9916  } if rt > 71.6135
        values = { t: 16.0, start:  74.9916, end:  78.5505  } if rt > 74.9916
        values = { t: 15.0, start:  78.5505, end:  82.3008  } if rt > 78.5505
        values = { t: 14.0, start:  82.3008, end:  86.2542  } if rt > 82.3008
        values = { t: 13.0, start:  86.2542, end:  90.4228  } if rt > 86.2542
        values = { t: 12.0, start:  90.4228, end:  94.8197  } if rt > 90.4228
        values = { t: 11.0, start:  94.8197, end:  99.4589  } if rt > 94.8197
        values = { t: 10.0, start:  99.4589, end: 104.3552  } if rt > 99.4589
        values = { t:  9.0, start: 104.3552, end: 109.5245  } if rt > 104.3552
        values = { t:  8.0, start: 109.5245, end: 114.9837  } if rt > 109.5245
        values = { t:  7.0, start: 114.9837, end: 120.7510  } if rt > 114.9837
        values = { t:  6.0, start: 120.7510, end: 126.8458  } if rt > 120.7510
        values = { t:  5.0, start: 126.8458, end: 133.2887  } if rt > 126.8458
        values = { t:  4.0, start: 133.2887, end: 140.1019  } if rt > 133.2887
        values = { t:  3.0, start: 140.1019, end: 147.3091  } if rt > 140.1019
        values = { t:  2.0, start: 147.3091, end: 154.9356  } if rt > 147.3091
        values = { t:  1.0, start: 154.9356, end: 163.0086  } if rt > 154.9356
        values = { t:  0.0, start: 163.0086, end: 171.5571  } if rt > 163.0086
        values = { t: -1.0, start: 171.5571, end: 180.6125  } if rt > 171.5571
        values = { t: -2.0, start: 180.6125, end: 190.2080  } if rt > 180.6125
        values = { t: -3.0, start: 190.2080, end: 200.3796  } if rt > 190.2080
        values = { t: -4.0, start: 200.3796, end: 211.1656  } if rt > 200.3796
        values = { t: -5.0, start: 211.1656, end: 222.6075  } if rt > 211.1656
        temperature = (values[:t] - 1) + (values[:end] - rt)/(values[:end]-values[:start])
      end
    end

    temperature

  end