Lesson 7: Logging Data

When your code runs in space, you won't be there to watch the screen. You need to record everything that happens to a file so you can analyze it later.

Session Goals

Use the logzero library.
Understand Log Levels (Info, Warning, Error).
Write sensor data to a Log File.

The Mission Task

We need to create a reliable data logger that records the temperature and humidity at regular intervals. This data is crucial for the experiment analysis.

Key Concepts

Logging: The process of recording events, messages, and data to a file for permanent storage.
Log Levels: Categories of logs: INFO (normal events), WARNING (potential issues), ERROR (failures).
CSV Format: Comma-Separated Values. A common text format for data where each value is separated by a comma.

Mission Challenge: Data Logger

Objective: Continuously record environmental data to a log file.

Instructions:

Create a for loop that runs 5 times.
Inside the loop, use sense.get_temperature() and sense.get_humidity().
Format the data into a string (e.g., "Temp=25.0, Hum=45.0").
Use logger.info() to save this string to the log file.
Add a time.sleep(1) delay.
Finally, log a "Mission Complete" message.

Logzero

Robust and easy-to-use logging for Python.

from logzero import logger, logfile

Usage	Description
logfile("file.log")	Set the file to write logs to.
logger.info(msg)	Log an informational message.
logger.warning(msg)	Log a warning message.
logger.error(msg)	Log an error message.

Sense HAT

Controls the LED matrix and reads environmental sensors.

from sense_hat import SenseHat

Usage	Description
sense.get_temperature()	Get temperature in Celsius.
sense.get_humidity()	Get relative humidity (%).

Mission Control Interface

Output Terminal

Ready to execute...