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Get reading from Nova PM Sensor SDS011 (dust sensor, air quality sensor, PM10, PM2,5)
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| #!/usr/bin/env python3 | |
| """ | |
| Get reading from Nova PM Sensor SDS011 | |
| (dust sensor, air quality sensor, PM10, PM2,5) | |
| Designed to run from cron and append CSV file. | |
| Script tested using Python3.4 on Ubuntu 14.04. | |
| TODO: choose by dev name using udev, add dev id info, python package pyudev | |
| udevadm info -q property --export /dev/ttyUSB0 | |
| """ | |
| import os | |
| import csv | |
| import io | |
| import logging | |
| import datetime | |
| import argparse | |
| try: | |
| import serial | |
| except ImportError: | |
| print('Python serial library required, on Ubuntu/Debian:') | |
| print(' apt-get install python-serial python3-serial') | |
| raise | |
| LOG_FORMAT = '%(asctime)-15s %(levelname)-8s %(message)s' | |
| def append_csv(filename, field_names, row_dict): | |
| """ | |
| Create or append one row of data to csv file. | |
| """ | |
| file_exists = os.path.isfile(filename) | |
| with io.open(filename, 'a', encoding='utf-8') as csvfile: | |
| writer = csv.DictWriter(csvfile, | |
| delimiter=',', | |
| lineterminator='\n', | |
| fieldnames=field_names) | |
| if not file_exists: | |
| writer.writeheader() | |
| writer.writerow(row_dict) | |
| def read_nova_dust_sensor(device='/dev/ttyUSB0'): | |
| dev = serial.Serial(device, 9600) | |
| if not dev.isOpen(): | |
| dev.open() | |
| msg = dev.read(10) | |
| assert msg[0] == ord(b'\xaa') | |
| assert msg[1] == ord(b'\xc0') | |
| assert msg[9] == ord(b'\xab') | |
| pm25 = (msg[3] * 256 + msg[2]) / 10.0 | |
| pm10 = (msg[5] * 256 + msg[4]) / 10.0 | |
| checksum = sum(v for v in msg[2:8]) % 256 | |
| assert checksum == msg[8] | |
| return {'PM10': pm10, 'PM2_5': pm25} | |
| def main(): | |
| logging.basicConfig(format=LOG_FORMAT, level=logging.INFO) | |
| parser = argparse.ArgumentParser(description='Read data from Nova PM sensor.') | |
| parser.add_argument('--device', default='/dev/ttyUSB0', | |
| help='Device file of connected by USB RS232 Nova PM sensor') | |
| parser.add_argument('--csv', default=None, | |
| help='Append results to csv, you can use year, month, day in format') | |
| args = parser.parse_args() | |
| data = read_nova_dust_sensor(args.device) | |
| logging.info('PM10=% 3.1f ug/m^3 PM2.5=% 3.1f ug/m^3', data['PM10'], data['PM2_5']) | |
| if args.csv: | |
| field_list = ['date', 'PM10', 'PM2_5'] | |
| today = datetime.datetime.today() | |
| data['date'] = today.strftime('%Y-%m-%d %H:%M:%S') | |
| csv_file = args.csv % {'year': today.year, | |
| 'month': '%02d' % today.month, | |
| 'day': '%02d' % today.day, | |
| } | |
| append_csv(csv_file, field_list, data) | |
| if __name__ == '__main__': | |
| main() |
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