turn handler into module

gpio_handler/__init__.py

@@ -0,0 +1,75 @@
+import os
+import time
+import RPi.GPIO as GPIO
+
+'''
+Pinout:
+* P26 ----> r_ch1
+* P20 ----> r_ch2
+* P21 ----> r_ch3
+'''
+# Channels
+r_ch1 = 26
+r_ch2 = 20
+r_ch3 = 21
+
+# time constants in seconds
+t_large_beer = 6
+t_small_beer = 2
+
+# double tap
+t_left_tap = 6
+t_right_tap = 6
+t_flush = 20
+
+# Syntax suger because of negative logic
+S_ON = GPIO.LOW
+S_OFF = GPIO.HIGH
+
+def __setup_GPIO(channel=r_ch1):
+    """
+        Setup all GPIOs, set output mode, and set gpio mode to bcm
+    """
+    GPIO.setwarnings(False)
+    GPIO.setmode(GPIO.BCM)
+
+    print("setting up gpio_{}".format(channel))
+    GPIO.setup(channel, GPIO.OUT)
+    __set_gpio(channel, S_OFF)
+
+def __set_gpio(channel=r_ch1, value=S_OFF):
+    """
+        Try to safely change the value of a gpio, catch exception if it fails
+        TODO: Exception Handling
+    """
+    try:
+        GPIO.output(channel, value)
+    except:
+        print("GPIO Error")
+        GPIO.cleanup()
+
+def gpio_test():
+    """
+        Test all channels
+    """
+    for i, gpio in enumerate([r_ch1, r_ch2, r_ch3], start=1):
+        # Setup gpio pin
+        __setup_GPIO(gpio)
+
+        __set_gpio(gpio, S_ON)
+        print("Channel_{}: gpio_{} on".format(i, gpio))
+        time.sleep(0.1)
+        __set_gpio(gpio, S_OFF)
+        print("Channel_{}: gpio_{} off".format(i, gpio))
+        time.sleep(0.1)
+
+def draw_beer(channel=r_ch1, wait=t_large_beer):
+    """
+        Draw a delicious beer, keep the tap on for n_wait seconds
+    """
+    # Setup gpio pin
+    __setup_GPIO(channel)
+
+    __set_gpio(channel, S_ON)
+    time.sleep(wait)
+    __set_gpio(channel, S_OFF)