Created
March 29, 2017 07:19
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Send 1-wire temperature values from a Raspberry Pi to an MQTT broker
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from __future__ import print_function | |
import os | |
import time | |
import paho.mqtt.client as mqtt | |
from paho.mqtt.client import MQTT_ERR_SUCCESS, MQTT_ERR_NO_CONN | |
DEVICES_PATH = "/sys/bus/w1/devices" | |
MQTT_HOST = "localhost" | |
MQTT_PORT = 1883 | |
SLEEP_TIME = 30 | |
def connect_mqtt(): | |
mqttc = mqtt.Client() | |
print("Connecting to {}".format(MQTT_HOST)) | |
mqttc.connect(MQTT_HOST, MQTT_PORT, 60) | |
print("Connected") | |
mqttc.loop_start() | |
mqttc.on_disconnect = on_disconnect | |
return mqttc | |
def disconnect_mqtt(mqttc): | |
mqttc.loop_stop() | |
mqttc.disconnect() | |
def on_disconnect(client, userdata, rc): | |
if rc != 0: | |
print("Unexpected disconnection.") | |
client.reconnect() | |
def get_thermometer_names(): | |
thermometers = [x[1] for x in os.walk(DEVICES_PATH)][0] | |
while "w1_bus_master1" in thermometers: thermometers.remove("w1_bus_master1") | |
return thermometers | |
def get_thermometer_temp(thermometer): | |
with open("{}/{}/w1_slave".format(DEVICES_PATH, thermometer), "r") as tfile: | |
text = tfile.read() | |
secondline = text.split("\n")[1] | |
temperaturedata = secondline.split(" ")[9] | |
temperature = float(temperaturedata[2:]) | |
temperature = temperature / 1000 | |
return temperature | |
def publish_temp(mqttc, thermometer, temp): | |
topic = "raspberry-pi/w1/thermometer/{}".format(thermometer) | |
(result, mid) = mqttc.publish(topic, temp) | |
if result == MQTT_ERR_SUCCESS: | |
print("Published {} to {}".format(temp, topic)) | |
elif result == MQTT_ERR_NO_CONN: | |
print("Connection error") | |
else: | |
print("Unknown error") | |
def main(): | |
print("Starting") | |
try: | |
mqttc = connect_mqtt() | |
thermometers = get_thermometer_names() | |
print("Detected {} thermometers".format(len(thermometers))) | |
while True: | |
for thermometer in thermometers: | |
temp = get_thermometer_temp(thermometer) | |
publish_temp(mqttc, thermometer, temp) | |
time.sleep(SLEEP_TIME) | |
except KeyboardInterrupt: | |
print("Exiting") | |
finally: | |
print("Disconnecting from {}".format(MQTT_HOST)) | |
disconnect_mqtt(mqttc) | |
print("Done") | |
if __name__ == "__main__": | |
main() |
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