Raspi data logger, version 1.2020.02.06

bmp280_tupla.py

+#!/usr/bin/python3
+#/home/pi/bmp280_tupla.py
+
+# Author: Jarkko Hanhela
+# Date: 4.10.2019
+
+import os
+os.chdir('/home/pi/')
+import sys
+import time
+from datetime import datetime
+import digitalio
+import busio
+import board
+import adafruit_bmp280
+from tendo import singleton
+
+
+# Next line will stop this instance if there already is a running instance of the program
+me = singleton.SingleInstance()
+
+# This is the time between two measurements in seconds.
+# 600 = 10 min
+timeperiod = 120
+
+# Define the name of the file that shall contain the measurement data.
+# The fileversion numbers (to prevent overwriting data by mistake) and filetype '.csv' will be
+# automatically appended to the variable $filename determined here.
+# The file will be saved to a folder named "p-T_data".
+#filename = 'both_sensors_in_closed_DUT_indoors'
+filename = '3-measure_after_startup_test'
+fileversion = 1
+
+# Check if current version for the filename already exists, and make new version.
+while os.path.isfile('p-T_data/' + filename + '-' + str(fileversion) + '.csv'):
+    fileversion += 1
+
+# Compile the full filename.
+filename = 'p-T_data/' + filename + '-' + str(fileversion) + '.csv'
+print(filename)
+
+# Initialize the SPI connection for the two bmp280 sensors.
+spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
+bmp_inside_cs = digitalio.DigitalInOut(board.D5)    #CS inside = pin 5
+bmp_outside_cs = digitalio.DigitalInOut(board.D6)   #CS outside = pin 6
+
+# Let's make a connection to the sensor inside
+try:
+    bmp280_inside = adafruit_bmp280.Adafruit_BMP280_SPI(spi, bmp_inside_cs)
+except Exception as ex:
+    file = open('p-T_data/error_log.txt', 'w')
+    file.write(datetime.strftime(datetime.now(), "%Y-%m-%d %H:%M:%S")+"; "+str(ex) +"\n")
+    file.close()
+    print(ex)
+
+# Same for sensor outside
+try:
+    bmp280_outside = adafruit_bmp280.Adafruit_BMP280_SPI(spi, bmp_outside_cs)
+except Exception as ex:
+    file = open('p-T_data/error_log.txt', 'w')
+    file.write(datetime.strftime(datetime.now(), "%Y-%m-%d %H:%M:%S")+"; "+str(ex)+"\n")
+    file.close()
+    print(ex)
+
+
+# Print a header for the new datafile named by $filename.
+file = open(filename, 'w')
+file.write("Timestamp, p_inside[Pa], T_inside[degC], p_outside[Pa], T_outside[degC]\n")
+file.close()
+
+# Make the data format for pressure and temperature to have just 4 digits
+dataformat = "{:0.4f}"
+
+# Start the measurement and loop until the program is stopped.
+while True:
+    
+    # Print the temperature and pressure data from the sensors
+    # and the current time from Raspberry Pi before reading data from the sensors.
+    time_before_reading = datetime.now()
+    print(str(time_before_reading))
+    #print(datetime.strftime(time_before_reading, "%Y-%m-%d %H:%M:%S"))
+    #print("\n\nPressure inside: %0.1f Pa" % (bmp280_inside.pressure*100))
+    #print("Temperature inside: %0.1f C" % bmp280_inside.temperature)
+    #print("\nPressure outside: %0.1f Pa" % (bmp280_outside.pressure*100))
+    #print("Temperature outside: %0.1f C" % bmp280_outside.temperature)
+
+
+    # Write the data from the sensors to the datafile.
+    file = open(filename, 'a+')
+    try:
+        file.write(datetime.strftime(time_before_reading, "%Y-%m-%d %H:%M:%S") + ','
+                   + dataformat.format(bmp280_inside.pressure*100) + ','
+                   + dataformat.format(bmp280_inside.temperature) + ','
+                   + dataformat.format(bmp280_outside.pressure*100) + ','
+                   + dataformat.format(bmp280_outside.temperature) + '\n')
+        
+    # The connection to the datafile is closed after each write,
+    # so the file should not corrupt even due to an unexpected power-off
+    finally:
+        file.close()
+
+    # Sleep for the defined time period minus the time taken by reading and writing data
+    sleeptime = timeperiod - (datetime.now().timestamp() - time_before_reading.timestamp())
+    if sleeptime < 0:
+        sleeptime = 0.0
+    
+    time.sleep(sleeptime)
+
+        
+