improve gpio handler

beertap/views.py

@@ -1,7 +1,7 @@
 import json
 
 from flask import Blueprint, render_template, request, flash, jsonify
-from gpio_handler import gpio_test, draw_beer
+from gpio_handler import gpio_set_pulse
 
 views = Blueprint('views', __name__)
 
@@ -22,10 +22,10 @@ def render():
 def choice():
     if request.form['submit_button'] == 'option_1':
         print("Eis usem lingge Gütterli uselah!")
-        draw_beer(channel=r_ch1, wait=t_large_beer)
+        gpio_set_pulse(channel=r_ch1, time_on=t_large_beer)
     if request.form['submit_button'] == 'option_2':
         print("Eis usem rächte Gütterli uselah!")
-        draw_beer(channel=r_ch2, wait=t_large_beer)
+        gpio_set_pulse(channel=r_ch2, time_on=t_large_beer)
     return render_template('beertap.html')
 
 @views.route('/about', methods=['GET'])

gpio_handler/__init__.py

@@ -1,75 +1,20 @@
-import os
-import time
-import RPi.GPIO as GPIO
+'''
+Raspi pinout:
+- P26: r_ch1
+- P20: r_ch2
+- P21: r_ch3
+'''
 
-'''
-Pinout:
-* P26 ----> r_ch1
-* P20 ----> r_ch2
-* P21 ----> r_ch3
-'''
 # Channels
 r_ch1 = 26
 r_ch2 = 20
 r_ch3 = 21
+channels = [r_ch1, r_ch2, r_ch3]
 
-# 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)
+def create_output():
+    '''
+        Sets up the gpios to be used as outputs
+    '''
+    from .gpio import GPIOHandler
+    output_handler = GPIOHandler(channels)
+    return output_handler

gpio_handler/gpio.py

@@ -0,0 +1,70 @@
+'''
+    GPIO module to handle the gpios on our beertap.
+'''
+
+import time
+import RPi.GPIO as gpio
+
+class GPIOHandler:
+    '''
+        Class which takes care of handling the gpio pins.
+    '''
+
+    # constants for syntactical purposes
+    S_ON = gpio.LOW
+    S_OFF = gpio.HIGH
+
+    # gpio list
+    gpio_list=[]
+
+    def __init__(self, gpio_list):
+        '''
+            Contructor which takes a list of gpio pins
+            and sets them all up to be used as output.
+        '''
+        for pin in gpio_list:
+            self.gpio_list.append(pin)
+            self.__setup_gpio(pin)
+
+    def __set_gpio(self, channel=1, value=0):
+        '''
+            Try to safely change the value of a given gpio
+            and cleanup in case of an error.
+        '''
+        try:
+            gpio.output(channel, value)
+        except:
+            print("GPIO Error")
+            gpio.cleanup()
+
+    def __setup_gpio(self, channel=1):
+        '''
+            Takes a gpio channel, sets it to output mode
+            and set gpio mode to BCM.
+        '''
+        print(f"setting up gpio_{channel}")
+        gpio.setwarnings(False)
+        gpio.setmode(gpio.BCM)
+        gpio.setup(channel, gpio.OUT)
+        self.__set_gpio(channel, self.S_OFF)
+
+    def gpio_test(self):
+        '''
+            Test all configured channels
+        '''
+        for pin in self.gpio_list:
+            self.__set_gpio(pin, self.S_ON)
+            print(f"gpio_{pin}: on")
+            time.sleep(0.1)
+            self.__set_gpio(pin, self.S_OFF)
+            print(f"gpio_{pin}: off")
+            time.sleep(0.1)
+
+    def gpio_set_pulse(self, channel=1, time_on=1):
+        '''
+            Sets the state of a given gpio pin to ON for a given amount of time
+            then toggels it back to the previous state.
+        '''
+        self.__set_gpio(channel, self.S_ON)
+        time.sleep(time_on)
+        self.__set_gpio(channel, self.S_OFF)

main.py

@@ -1,8 +1,9 @@
 from beertap import create_app
-from gpio_handler import gpio_test
+from gpio_handler import create_output
 
 app = create_app()
+output = create_output()
 
 if __name__ == "__main__":
-    gpio_test()
+    output.gpio_test()
     app.run(debug=True)