Data Collection Guide

The SnifferBuddy project comes with software that listens for the SnifferBuddy readings coming in over mqtt and:

This way, any UI that can read/write DuckDB tables can be used to view the data. The software is designed to be run on a Raspberry Pi.

How the Code Works

The workflow for handling SnifferBuddy readings involves the following steps:

Starting the Workflow
The process begins with the start_capture.py script, which initializes the capture and processing of readings.
Listening for Readings
The mqtt_code.py script uses MQTT to listen for SnifferBuddy readings. It receives the data and processes it.
Processing the Readings
The readings are transformed into a SCD4XSensorReading Pydantic model, which includes the calculation of vpd (vapor pressure deficit).
- VPD Calculation: The vpd is derived using the temperature and relative humidity from the reading.
- Assumption: Leaf temperature is assumed to be 2°C lower than the air temperature.
Storing the Processed Data
The processed reading is passed to database_code.py, which saves it into the sniffer_data.duckdb database file.

The schema consists of one table, the readings table.

Below is a detailed description of each column in the schema:

Column Name	Data Type	Description
`timestamp`	`TIMESTAMP`	The primary key. Indicates the time the reading was taken.
`device_name`	`TEXT`	The name or identifier of the SnifferBuddy device providing the reading.
`light_on`	`BOOLEAN`	Indicates whether the light was on (`TRUE`) or off (`FALSE`) during the reading.
`CO2`	`INTEGER`	The CO2 concentration level measured in parts per million (ppm).
`temperature`	`REAL`	The air temperature at the time of the reading.
`humidity`	`REAL`	The relative humidity percentage recorded.
`vpd`	`REAL`	The calculated vapor pressure deficit (in kPa).
`dew_point`	`REAL`	The dew point temperature.
`temp_unit`	`TEXT`	The unit of the temperature reading, `"C"` (Celsius) or `"F"` (Fahrenheit).

sudo apt update && sudo apt install pipx

go to: /lib/systemd/system

copy the snifferbuddy service file:

sudo systemctl enable snifferbuddy