Add pressure at sea level

Some code fact.

code/config_template.py

@@ -11,3 +11,5 @@ MQTT_PASSWD = "passwd"
 
 WIFI_SSID = "my_wifi_ssid"
 WIFI_PSK = "my_wifi_wpa_key"
+
+ALTITUDE = 150

code/main.py

@@ -1,4 +1,4 @@
-"""Station météo connectée au service Adafruit IO
+"""Station météo connectée vers MQTT via wifi
 """
 
 import time
@@ -45,6 +45,9 @@ bme.set_measurement_settings({
 
 # 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))
@@ -84,6 +87,8 @@ 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)
@@ -100,25 +105,28 @@ time.sleep_ms(1000)
 # - string format
 # - factor (multiplier)
 # - qos
-topics = {"humidity" : ["humidity/value", "{:.0f}", 1, 1],
+topics = {"time" : ["time/last_values", "{}", 1, 1],
+          "humidity" : ["humidity/value", "{:.0f}", 1, 1],
           "pressure" : ["pressure/value", "{:.2f}", 0.01, 1],
-          "temperature" : ["temperature/value", "{:.1f}", 1, 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()
-    meas_time = now()
+    bme_data['time'] = now()
-    print(meas_time, ":", bme_data)
+    bme_data['pressure2'] = bme_data['pressure']/SMLP_coef
-    print("Pt100:", max31865.temperature, "degC")
+    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=50)
+                    sleep=20)
-
-    MqttPublish(client, "temperature2/value", "{:.2f}".format(max31865.temperature))
-    MqttPublish(client, "wifi/rssi", "{:.0f}".format(wlan.status('rssi')))
-    MqttPublish(client, "time/last_values", meas_time, retain=True)
 
     time.sleep_ms(1000)