station-meteo/code/main.py

"""Station météo connectée vers MQTT via wifi
"""

import time
import machine
import network
import esp
import bme280_i2c
import adafruit_max31865
from ntptime import settime
from umqtt.robust import MQTTClient
import config


# connect to WLAN
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
nets = wlan.scan()
for net in nets:
    net_ssid = net[0].decode()
    if net_ssid == config.WIFI_SSID:
        print('Network found!')
        wlan.connect(net_ssid, config.WIFI_PSK)
        while not wlan.isconnected():
            machine.idle()  # save power while waiting
        print('WLAN connection succeeded!')
        break
if not wlan.isconnected():
    print("WLAN not found/not connected")

# Create a micropython I2C object with the appropriate device pins
i2c = machine.I2C(scl=machine.Pin(5), sda=machine.Pin(4))

# Create a sensor object to represent the BME280
# Note that this will error if the device can't be reached over I2C.
bme = bme280_i2c.BME280_I2C(address=bme280_i2c.BME280_I2C_ADDR_SEC, i2c=i2c)

# Configure the sensor for the application in question.
bme.set_measurement_settings({
    'filter': bme280_i2c.BME280_FILTER_COEFF_16,
    'standby_time': bme280_i2c.BME280_STANDBY_TIME_500_US,
    'osr_h': bme280_i2c.BME280_OVERSAMPLING_1X,
    'osr_p': bme280_i2c.BME280_OVERSAMPLING_16X,
    'osr_t': bme280_i2c.BME280_OVERSAMPLING_2X})

# Start the sensor automatically sensing
bme.set_power_mode(bme280_i2c.BME280_NORMAL_MODE)
# Conversion coeff. between measured pressure and Seau Mean-level pressure
# Source: https://fr.wikipedia.org/wiki/Pression-altitude
SMLP_coef=pow(1.0-((0.0065*config.ALTITUDE)/288.15), 5.255)

# PT100 (via max81865 module) sensor setup
spi=machine.SPI(-1, sck=machine.Pin(14, machine.Pin.OUT), mosi=machine.Pin(13, machine.Pin.OUT), miso=machine.Pin(12, machine.Pin.OUT))
spi.init(baudrate=115200, polarity=0, phase=1) #, firstbit=machine.SPI.MSB)
max31865_cs=machine.Pin(2)
max31865=adafruit_max31865.MAX31865(spi, max31865_cs)

# RTC setup
rtc=machine.RTC()
settime()


def now():
    """Return a string representing date/time now"""
    return "{0:04d}/{1:02d}/{2:02d}_{4:02d}:{5:02d}:{6:02d}".format(*rtc.datetime())


def MqttPublish(client, topic, message, retain=False, qos=0, sleep=10):
    """MQTT publish helper"""
    client.publish("test/{device}/{topic}".format(device=config.CLIENT_ID, topic=topic),
                   message,
                   retain=retain,
                   qos=qos)
    time.sleep_ms(sleep)


client = MQTTClient(client_id=config.CLIENT_ID,
                    server=config.MQTT_HOST,
                    user=config.MQTT_USERNAME,
                    password=config.MQTT_PASSWD,
                    port=config.MQTT_PORT)
client.connect()

MqttPublish(client, "last_boot", now())
MqttPublish(client, "location", config.LOCATION, retain=True, qos=1)
MqttPublish(client, "humidity/unit", "%", retain=True)
MqttPublish(client, "humidity/desc", "Capteur Bosch BME280", retain=True, qos=0)
MqttPublish(client, "pressure/unit", "hPa", retain=True, qos=0)
MqttPublish(client, "pressure/desc", "Capteur Bosch BME280", retain=True, qos=0)
MqttPublish(client, "pressure2/unit", "hPa", retain=True, qos=0)
MqttPublish(client, "pressure2/desc", "Capteur Bosch BME280 revenu au niveau de la mer", retain=True, qos=0)
MqttPublish(client, "temperature/unit", "degC", retain=True, qos=0)
MqttPublish(client, "temperature/desc", "Capteur Bosch BME280", retain=True, qos=0)
MqttPublish(client, "temperature2/unit", "degC", retain=True, qos=0)
MqttPublish(client, "temperature2/desc", "Sonde PT100/MAX31865", retain=True, qos=0)
MqttPublish(client, "wifi/ssid", config.WIFI_SSID, retain=True, qos=0)
MqttPublish(client, "wifi/ip", wlan.ifconfig()[0], retain=True, qos=0)
MqttPublish(client, "wifi/channel", "{:d}".format(net[2]), retain=True, qos=0)
MqttPublish(client, "sys/esp8266_device_id", "{:d}".format(esp.flash_id()), retain=True, qos=0)

time.sleep_ms(1000)

# For each nature, a list describes:
# - mqtt topic
# - string format
# - factor (multiplier)
# - qos
topics = {"time" : ["time/last_values", "{}", 1, 1],
          "humidity" : ["humidity/value", "{:.0f}", 1, 1],
          "pressure" : ["pressure/value", "{:.2f}", 0.01, 1],
          "pressure2" : ["pressure2/value", "{:.2f}", 0.01, 1],
          "temperature" : ["temperature/value", "{:.1f}", 1, 1],
          "temperature2" : ["temperature/value2", "{:.1f}", 1, 1],
          "wifi_rssi" : ["wifi/rssi", "{:.0f}", 1, 1],
          }

while 1:
    bme_data = bme.get_measurement()
    bme_data['time'] = now()
    bme_data['pressure2'] = bme_data['pressure']/SMLP_coef
    bme_data['temperature2'] = max31865.temperature
    bme_data['wifi_rssi'] = wlan.status('rssi')
    print(bme_data)

    for nature, param in topics.items():
        MqttPublish(client,
                    param[0],
                    param[1].format(bme_data[nature]*param[2]),
                    qos=param[3],
                    sleep=20)

    time.sleep_ms(1000)