#!/usr/bin/env python3.x
#
#-----------------------------------------------------------------------------
#
# Programme de publication sur MQTT de la pression du LPS25HB sur bus I2C
#
#-----------------------------------------------------------------------------

import paho.mqtt.client as mqtt
import smbus

# Recuperation des informations
# Donnees pour le LPS25HB dont son addresse sur cartelette Pololu 
address=0x5d
CTL_REG1=0x20
CTL_REG1_VALUE=0xb0
PRESS_OUT_XLauto=0xa8
# Ouverture du bus et echanges I2C
bus=smbus.SMBus(1)
data=bus.write_byte_data(address, CTL_REG1, CTL_REG1_VALUE) 
data=bus.read_i2c_block_data(address, PRESS_OUT_XLauto, 3)
pression=(data[0]+256*(data[1]+256*data[2]))/4096
pression=round(pression, 2)
if(pression<800):
  exit()
if(pression>1400):
  exit()
MQTT_MSG="Pre= %.2f mbar" % pression

# Configuration du mqtt
MQTT_BROKER = "localhost"
MQTT_PORT = 1883
MQTT_KEEPALIVE_INTERVAL = 45
MQTT_TOPIC = "Meteo/Capt00"

# Initiate MQTT Client
mqttc=mqtt.Client()

# Connect with MQTT Broker
mqttc.connect(MQTT_BROKER, MQTT_PORT, MQTT_KEEPALIVE_INTERVAL) 

# Publish message to MQTT Topic 
mqttc.publish(MQTT_TOPIC, MQTT_MSG)

# Disconnect from MQTT_Broker
mqttc.disconnect()