weather-data-sensor

This is a command line utility to read humidity, pressure, and temperature readings. The readings are written to a Mosquitto Queue with submission daemon that submits to a RESTful web service.

The sensor used for this application is the BME280 from Adafruit.

For remote debugging of python scripts that access the GPIO pins, refer to Remote Debug GPIO on Raspberry Pi.

Sensor Wiring

The connections for the sensor and the Raspberry Pi are given in the schematic below.

Configuration

The application's configuration file specifies the following:

• the address to submit the JSON encoded readings for humidity, pressure, and temperature.
• the error range for the sensor's humidity, pressure, and temperature readings.
• the wait time between measurements (60 seconds).

Humidity Output

The JSON formatting of humidity values are illustrated below.

Attribute	Datatype	Description
value	decimal	The humidity reading value
value_units	string	The units of the humidity value
value_error_range	decimal	The error range for sensor in units
timestamp	datetime	A UTC datetime the record was measured
elevation	decimal	The elevation that the record was measured
elevation_units	string	The units of the elevation value
longitude	decimal	The dotted decimal notation value of the latitude
longitude	decimal	The dotted decimal notation value of the longitude

An example of the JSON is given below.

{
    "value": 72.22,
    "value_units": "percent",
    "value_error_range": 0.001,
    "timestamp": "1990-12-25T23:59:59.12345Z",
    "elevation": 122,
    "elevation_units": "m",
    "latitude": -12.345678,
    "longitude": 0.1111
}

Pressure Output

The JSON formatting of pressure values are illustated below.

Attribute	Datatype	Description
value	decimal	The pressure reading value
value_units	string	The units of the pressure value
value_error_range	decimal	The error range for sensor in units
timestamp	datetime	A UTC datetime the record was measured
elevation	decimal	The elevation that the record was measured
elevation_units	string	The units of the elevation value
longitude	decimal	The dotted decimal notation value of the latitude
longitude	decimal	The dotted decimal notation value of the longitude

An example of the JSON is given below.

{
    "value": 72.22,
    "value_units": "kPa",
    "value_error_range": 0.001,
    "timestamp": "1990-12-25T23:59:59.12345Z",
    "elevation": 122,
    "elevation_units": "m",
    "latitude": -12.345678,
    "longitude": 0.1111
}

Temperature Output

The JSON formatting of temperature values are illustated below.

Attribute	Datatype	Description
value	decimal	The temperature reading value
value_units	string	The units of the temperature value
value_error_range	decimal	The error range for sensor in units
timestamp	datetime	A UTC datetime the record was measured
elevation	decimal	The elevation that the record was measured
elevation_units	string	The units of the elevation value
longitude	decimal	The dotted decimal notation value of the latitude
longitude	decimal	The dotted decimal notation value of the longitude

An example of the JSON is given below.

{
    "value": -10.12,
    "value_units": "C",
    "value_error_range": 0.001,
    "timestamp": "1990-12-25T23:59:59.12345Z",
    "elevation": 122,
    "elevation_units": "m",
    "latitude": -12.345678,
    "longitude": 0.1111
}