chickenhouse: add climate control

Signed-off-by: Thomas Klaehn <thomas.klaehn@u-blox.com>

climate_control/__init__.py

@@ -0,0 +1,95 @@
+'''
+Created on Aug 30, 2018
+
+@author: tkl
+'''
+import logging
+import socket
+import ssl
+import threading
+import time
+import paho.mqtt.client as mqtt
+from climate_control.sensors import Dht22
+from climate_control.heat import Heat
+
+MQTT_BROKER = "mqtt.blackfinn.de"
+MQTT_PORT = 8883
+MQTT_CERT = "/etc/ssl/certs/DST_Root_CA_X3.pem"
+MQTT_TEMPERATURE_TOPIC = "outdoor/chickenhouse/temperature"
+MQTT_HUMIDITY_TOPIC = "outdoor/chickenhouse/humidity"
+MQTT_ROOM_HEAT_TOPIC = "outdoor/chickenhouse/heat/room"
+MQTT_WATER_HEAT_TOPIC = "outdoor/chickenhouse/heat/water"
+
+WATER_HEAT_THRESHOLD = {"on": 1.0, "off": 2.0}
+ROOM_HEAT_THRESHOLD = {"on": 1.0, "off": 2.0}
+
+STATE_OFF = "off"
+STATE_ON = "ON"
+
+class ClimateControl(threading.Thread):
+    __water_heat = Heat(20)
+    __room_heat = Heat(21)
+    __climate = Dht22(26)
+    __thread_condition = True
+    __now = time.time()
+    __interval = 15 * 60
+    __next = time.time()
+    __water_heat_state = STATE_OFF
+    __room_heat_state = STATE_OFF
+
+    def __init__(self):
+        super(ClimateControl, self).__init__()
+
+    def __check_switch_water_heat(self, temperature):
+        ret = False
+        if temperature >= WATER_HEAT_THRESHOLD["off"] and self.__water_heat_state == STATE_ON:
+            self.__water_heat.off()
+            self.__water_heat_state = STATE_OFF
+            ret = True
+        elif temperature <= WATER_HEAT_THRESHOLD["on"] and self.__water_heat_state == STATE_OFF:
+            self.__water_heat.on()
+            self.__water_heat_state = STATE_ON
+            ret = True
+        return ret
+
+    def __check_switch_room_heat(self, temperature):
+        ret = False
+        if temperature >= ROOM_HEAT_THRESHOLD["off"] and self.__room_heat_state == STATE_ON:
+            self.__room_heat.off()
+            self.__room_heat_state = STATE_OFF
+            ret = True
+        elif temperature <= ROOM_HEAT_THRESHOLD["on"] and self.__room_heat_state == STATE_OFF:
+            self.__room_heat.on()
+            self.__room_heat_state = STATE_ON
+            ret = True
+        return ret
+
+    def run(self):
+        while self.__thread_condition:
+            self.__now = time.time()
+            if self.__next <= self.__now:
+                humidity, temperature = self.__climate.read()
+                try:
+                    client = mqtt.Client()
+                    client.tls_set(MQTT_CERT)
+                    client.connect(MQTT_BROKER, MQTT_PORT, 60)
+                    client.loop_start()
+                    msg = "{} {}".format(self.__now, temperature)
+                    client.publish(MQTT_TEMPERATURE_TOPIC, msg, qos=2, retain=True)
+                    msg = "{} {}".format(self.__now, humidity)
+                    client.publish(MQTT_HUMIDITY_TOPIC, msg, qos=2, retain=True)
+                    if self.__check_switch_water_heat(temperature):
+                        msg = "{} {}".format(self.__now, self.__water_heat_state)
+                        client.publish(MQTT_WATER_HEAT_TOPIC, msg, qos=2, retain=True)
+                    if self.__check_switch_room_heat(temperature):
+                        msg = "{} {}".format(self.__now, self.__room_heat_state)
+                        client.publish(MQTT_ROOM_HEAT_TOPIC, msg, qos=2, retain=True)
+                    client.loop_stop()
+                    client.disconnect()
+                except(ValueError, TypeError, socket.error, ssl.CertificateError):
+                    logging.info('unable to publish to mqtt')
+                self.__next = self.__now + self.__interval
+            time.sleep(1)
+
+    def stop(self):
+        self.__thread_condition = False

climate_control/heat.py

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+try:
+    import gpio
+except ImportError:
+    raise ImportError("gpio not found.")
+
+class Heat(object):
+    def __init__(self, pin):
+        self.pin = gpio.Gpio(pin)
+
+        self.pin.export()
+        self.pin.direction(gpio.Gpio.DIRECTION_OUT)
+
+        self.pin.write(0)
+
+    def on(self):
+        self.pin.write(1)
+
+    def off(self):
+        self.pin.write(0)

climate_control/sensors.py

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+'''Module for sensor implementations'''
+try:
+    import Adafruit_DHT
+except ImportError:
+    raise ImportError('Adafruit_DHT library not found.')
+
+def is_valid(temperature, humidity):
+    '''Check if temperature and humidity are valid.'''
+    return True if humidity <= 100.0 and humidity >= 0.0 and \
+                   temperature <= 100.0 and temperature >= -50.0 else False
+
+class Dht22(object):
+    '''DHT 22 temperature and Humidity sensor class.'''
+    sensor = 22
+    pin = int()
+
+    def __init__(self, pin):
+        self.pin = pin
+
+    def read(self):
+        '''Read temperature and humidity.'''
+        temperature = -200.0
+        humidity = -1.0
+        valid = False
+        while valid is False:
+            temperature, humidity = Adafruit_DHT.read_retry(self.sensor, self.pin)
+            valid = is_valid(temperature, humidity)
+        return temperature, humidity