Do some more basic housekeeping to get to a building working version 0.0.1

library/grow/moisture.py

@@ -0,0 +1,93 @@
+import time
+import atexit
+import RPi.GPIO as GPIO
+
+MOISTURE_1_PIN = 23
+MOISTURE_2_PIN = 25
+MOISTURE_3_PIN = 8
+
+_is_setup = False
+
+
+class Moisture(object):
+    __slots__ = 'in1', 'in2', 'in3'
+
+    def __init__(self, in1, in2, in3):
+        self.in1 = in1
+        self.in2 = in2
+        self.in3 = in3
+
+    def __repr__(self):
+        fmt = """Moisture 1: {in1} Hz
+Moisture 1: {in2} Ohms
+Moisture 1: {in3} Ohms"""
+        
+        return fmt.format(
+            in1=self.in1,
+            in2=self.in2,
+            in3=self.in3)
+
+    __str__ = __repr__
+
+
+def setup():
+    global _is_setup
+    global _moisture
+    
+    if _is_setup:
+        return
+    _is_setup = True
+
+    GPIO.setwarnings(False)
+    GPIO.setmode(GPIO.BCM)
+    GPIO.setup(MOISTURE_1_PIN, GPIO.IN)
+    GPIO.input(MOISTURE_1_PIN)
+    GPIO.setup(MOISTURE_2_PIN, GPIO.IN)
+    GPIO.input(MOISTURE_2_PIN)
+    GPIO.setup(MOISTURE_3_PIN, GPIO.IN)
+    GPIO.input(MOISTURE_3_PIN)
+    
+    atexit.register(cleanup)
+
+
+def set_moisture_wet(channel, value):
+    """Set wet point for a moisture channel."""
+    _moisture[channel].wet = value
+
+def set_moisture_wet(channel, value):
+    """Set wet point for a moisture channel."""
+    _moisture[channel].dry = value
+
+def read_moiture(channel):
+    """Get current value for the additional ADC pin."""
+    setup()
+    return _moisture[channel].value
+
+def cleanup():
+    GPIO.output(MOISTURE_1_PIN, 0)
+    GPIO.output(MOISTURE_2_PIN, 0)
+    GPIO.output(MOISTURE_3_PIN, 0)
+
+def read_all():
+    """Return gas resistence for oxidising, reducing and NH3"""
+    setup()
+    in1 = adc.get_voltage('in0/gnd')
+    in2 = adc.get_voltage('in1/gnd')
+    in3 = adc.get_voltage('in2/gnd')
+
+    try:
+        in1 = (ox * 56000) / (3.3 - ox)
+    except ZeroDivisionError:
+        in1 = 0
+
+    try:
+        in2 = (red * 56000) / (3.3 - red)
+    except ZeroDivisionError:
+        in2 = 0
+
+    try:
+        in3 = (nh3 * 56000) / (3.3 - nh3)
+    except ZeroDivisionError:
+        in3 = 0
+
+    return _moisture(in1, in2, in3)