pressure_sampler - bruno-beloff/scs_dev GitHub Wiki
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DESCRIPTION
The pressure_sampler utility reads an ICP-10101 or MPL115A2 digital barometer. It reports pressure in kilopascals and temperature in Centigrade. The utility always reports the actual atmospheric pressure (pA). It additionally reports temperature and equivalent pressure at sea level (p0) depending on whether the host device's altitude has been configured and the MPL115A2's temperature sensor has been calibrated:
| Altitude configuration | Temperature calibration | pA | P0 | tmp |
|---|---|---|---|---|
| not set | not set | yes | no | no |
| not set | set | yes | no | yes |
| set | not set | yes | no | no |
| set | set | yes | yes | yes |
The pressure_sampler writes its output to stdout. As for all sensing utilities, the output format is a JSON document with fields for:
- the unique tag of the device (if the system ID is set)
- the recording datetime in ISO 8601 format
- a value field containing the sensed values
Command-line options allow for single-shot reading, multiple readings with specified time intervals, or readings controlled by an independent scheduling process via a Unix semaphore.
SYNOPSIS
pressure_sampler.py [{ -s SEMAPHORE | -i INTERVAL [-n SAMPLES] }] [{ -v | -d }]
| Options | |
|---|---|
| --version | show program's version number and exit |
| -h, --help | show this help message and exit |
| -s SEMAPHORE, --semaphore=SEMAPHORE | sampling controlled by SEMAPHORE |
| -i INTERVAL, --interval=INTERVAL | sampling interval in seconds |
| -n SAMPLES, --samples=SAMPLES | number of samples (1 if interval not specified) |
| -v, --verbose | report narrative to stderr |
| -d, --debug | report detailed narrative to stderr |
EXAMPLES
./pressure_sampler.py -i10
FILES
~/SCS/conf/mpl115a2_calib.json
~/SCS/conf/pressure_conf.json
~/SCS/conf/schedule.json
~/SCS/conf/system_id.json
DOCUMENT EXAMPLE - v0
{"rec": "2021-10-06T11:34:18Z", "tag": "scs-be2-3", "val": {"bar": {"pA": 102.3, "p0": 103.5, "tmp": 24.0}}}
DOCUMENT EXAMPLE - v1
{"rec": "2021-10-11T11:08:24Z", "tag": "scs-be2-3", "ver": 1.0, "val": {"bar": {"pA": 103.5, "p0": 104.7, "tmp": 22.6}}}
SEE ALSO
scs_dev/climate_sampler
scs_dev/scheduler
scs_mfr/mpl115a2_calib
scs_mfr/pressure_conf
scs_mfr/schedule
scs_mfr/system_id