Update sensor value checking. (#24)

* Update sensor value checking.

greenpithumb/adc.py

@@ -1,7 +1,7 @@
 # TODO(mtlynch): Move these pin constants to a configuration file so they're not
 # hardcoded in.
 
-# ADC pin to which water pump is connected
+# ADC pin to which each component is connected
 PIN_PUMP = 0
 PIN_LIGHT_SENSOR = 1
 PIN_MOISTURE_SENSOR = 2
@@ -14,6 +14,9 @@
 # Signal to turn an ADC pin on.
 SIGNAL_ON = 1023
 
+PIN_MIN_VALUE = 0
+PIN_MAX_VALUE = 1023
+
 
 class Adc(object):
     """Wrapper for an MCP3008 analog to digital converter (ADC).

greenpithumb/light_sensor.py

@@ -1,7 +1,7 @@
 import adc
 
-_LIGHT_SENSOR_MAX_VALUE = 1023.0
 _LIGHT_SENSOR_MIN_VALUE = 290.0
+_LIGHT_SENSOR_MAX_VALUE = adc.PIN_MAX_VALUE
 
 
 class LightSensor(object):
@@ -18,11 +18,9 @@ def __init__(self, adc):
 
     def get_light_level(self):
         """Returns light level as percentage."""
-
         light_level = self._adc.read_pin(adc.PIN_LIGHT_SENSOR)
 
-        if light_level < _LIGHT_SENSOR_MIN_VALUE or \
-        light_level > _LIGHT_SENSOR_MAX_VALUE:
+        if light_level < _LIGHT_SENSOR_MIN_VALUE:
             raise ValueError('Light sensor reading out of range')
 
         light_level_as_pct = 100 * (

greenpithumb/moisture_sensor.py

@@ -1,9 +1,5 @@
 import adc
 
-#placeholder values
-_MIN_MOISTURE_LEVEL = 0.0
-_MAX_MOISTURE_LEVEL = 1023.0
-
 
 class MoistureSensor(object):
     """Wrapper for DHT11 moisture sensor."""
@@ -19,11 +15,4 @@ def __init__(self, adc):
 
     def moisture(self):
         """Returns moisture level."""
-        moisture_level = self._adc.read_pin(adc.PIN_MOISTURE_SENSOR)
-
-        if moisture_level < _MIN_MOISTURE_LEVEL or \
-        moisture_level > _MAX_MOISTURE_LEVEL:
-            raise ValueError('moisture level out of range: %.1f' %
-                             moisture_level)
-
-        return moisture_level
+        return self._adc.read_pin(adc.PIN_MOISTURE_SENSOR)

greenpithumb/pump.py

@@ -1,3 +1,5 @@
+import adc
+
 # Pump rate in mL/s (4.3 L/min)
 _PUMP_RATE_ML_PER_SEC = 4300.0 / 60.0
 
@@ -28,11 +30,11 @@ def pump_water(self, amount_ml):
         elif amount_ml < 0.0:
             raise ValueError('Cannot pump a negative amount of water')
         else:
-            self._adc.write_pin(0, 1023)
+            self._adc.write_pin(adc.PIN_PUMP, adc.SIGNAL_ON)
 
             wait_time_seconds = amount_ml / _PUMP_RATE_ML_PER_SEC
             self._clock.wait(wait_time_seconds)
 
-            self._adc.write_pin(0, 0)
+            self._adc.write_pin(adc.PIN_PUMP, adc.SIGNAL_OFF)
 
         return

greenpithumb/reservoir.py

@@ -1,4 +1,9 @@
-import weight_sensor
+class Error(Exception):
+    pass
+
+
+class ReservoirUnderWeightError(Error):
+    pass
 
 
 class Reservoir(object):
@@ -17,9 +22,11 @@ def __init__(self, weight_sensor, container_weight):
     def reservoir_level(self):
         """Returns reservoir level in ml."""
         reservoir_weight_grams = self._weight_sensor.weight()
-        water_weight_grams = reservoir_weight_grams - self._container_weight
-        if water_weight_grams < weight_sensor.MIN_WEIGHT:
-            raise ValueError('Water level out of range: %.1f' %
-                             water_weight_grams)
+        if reservoir_weight_grams < self._container_weight:
+            raise ReservoirUnderWeightError(
+                ('Unexpected weight measured for reservoir (%.1f g), as it is '
+                 'less than the weight of an empty reservoir (%.1f g).') % (
+                     reservoir_weight_grams, self._container_weight))
 
+        water_weight_grams = reservoir_weight_grams - self._container_weight
         return water_weight_grams  #1 gr water ~ 1 ml water

greenpithumb/weight_sensor.py

@@ -1,8 +1,5 @@
 import adc
 
-MIN_WEIGHT = 0.0
-_MAX_WEIGHT = 1023.0
-
 
 class WeightSensor(object):
     """Wrapper for a weight sensor."""
@@ -19,8 +16,6 @@ def __init__(self, adc):
     def weight(self):
         """Returns weight in grams."""
         weight = self._adc.read_pin(adc.PIN_WEIGHT_SENSOR)
-        if not MIN_WEIGHT <= weight <= _MAX_WEIGHT:
-            raise ValueError('reservoir weight out of range: %.1f' % weight)
 
         # TODO(JeetShetty): Implement the actual conversion from weight to
         # weight_grams

tests/test_light_sensor.py

@@ -15,7 +15,7 @@ def setUp(self):
 
     def test_light_50_pct(self):
         """Midpoint light sensor value should return 50.0."""
-        # Midpoint between LIGHT_SENSOR_MIN_VALUE and LIGHT_SENSOR_MAX_VALUE
+        # Midpoint between LIGHT_SENSOR_MIN_VALUE and PIN_MAX_VALUE
         self.mock_adc.read_pin.return_value = 656.5
 
         light_level = self.light_sensor.get_light_level()
@@ -27,10 +27,3 @@ def test_light_level_too_low(self):
             self.mock_adc.read_pin.return_value = (
                 light_sensor._LIGHT_SENSOR_MIN_VALUE - 1)
             self.light_sensor.get_light_level()
-
-    def test_light_level_too_high(self):
-        """Light sensor value greater than max should raise a ValueError."""
-        with self.assertRaises(ValueError):
-            self.mock_adc.read_pin.return_value = (
-                light_sensor._LIGHT_SENSOR_MAX_VALUE + 1)
-            self.light_sensor.get_light_level()

tests/test_moisture_sensor.py

@@ -15,21 +15,6 @@ def setUp(self):
 
     def test_moisture_50(self):
         """Moisture level read should be moisture level returned."""
-
         self.mock_adc.read_pin.return_value = 50.0
         moisture_level = self.moisture_sensor.moisture()
         self.assertEqual(moisture_level, 50.0)
-
-    def test_moisture_too_low_raises_ValueError(self):
-
-        with self.assertRaises(ValueError):
-            self.mock_adc.read_pin.return_value = (
-                moisture_sensor._MIN_MOISTURE_LEVEL - 1)
-            self.moisture_sensor.moisture()
-
-    def test_moisture_too_high_raises_ValueError(self):
-
-        with self.assertRaises(ValueError):
-            self.mock_adc.read_pin.return_value = (
-                moisture_sensor._MAX_MOISTURE_LEVEL + 1)
-            self.moisture_sensor.moisture()

tests/test_reservoir.py

@@ -18,7 +18,7 @@ def test_water_level_in_range(self):
         self.assertAlmostEqual(5.0, res.reservoir_level())
 
     def test_water_level_out_of_range(self):
-        with self.assertRaises(ValueError):
+        with self.assertRaises(reservoir.ReservoirUnderWeightError):
             container_weight = 50.0
             res = reservoir.Reservoir(self.mock_weight_sensor, container_weight)
             self.mock_weight_sensor.weight.return_value = container_weight - 1

tests/test_weight_sensor.py

@@ -18,13 +18,3 @@ def test_weight_500(self):
         self.mock_adc.read_pin.return_value = 500.0
         weight = self.weight_sensor.weight()
         self.assertEqual(weight, 500.0)
-
-    def test_weight_too_low_raises_ValueError(self):
-        with self.assertRaises(ValueError):
-            self.mock_adc.read_pin.return_value = weight_sensor.MIN_WEIGHT - 1
-            self.weight_sensor.weight()
-
-    def test_weight_too_high_raises_ValueError(self):
-        with self.assertRaises(ValueError):
-            self.mock_adc.read_pin.return_value = weight_sensor._MAX_WEIGHT + 1
-            self.weight_sensor.weight()