https://www.rigacci.org/wiki/doku.php/doc/appunti/hardware/raspberrypi_air
A monitoring station for air quality based on the Raspberry Pi
The lib/pms5003 is a Python script to read data from the PMS5003 particulate matter sensor by Plantower. It uses the serial line. It is rather complicated because it has all the following features:
- Handle sleep-down and awake of the sensor.
- Wait some time before read, allow the sensor to settle.
- Multiple read with average calculation.
- Verify data checksum.
- Handle communication errors.
- Single read or endless loop.
- Write data to status file (STATUS_FILE).
- Log to stdout/file/syslog.
The Single Read Mode is suitable for a cronjob: set SLEEP_BETWEEN_READS to -1. The sensor will be awakened before the reading, and it will be put at sleep before program exit.
For the Endless Loop Mode set SLEEP_BETWEEN_READS to the acquiring interval (seconds). If the interval is greather than three times the sensor's settling time, the sensor will be put to sleep before the next read.