Solution: Data Retrieval and Plotting Techniques

Data Retrieval

Data retrieval means reading stored or acquired data from a microcontroller, data logger or computer for further processing and visualization.

Common methods

1. UART/Serial: Simple method for transferring measurements to a PC terminal or application.
2. USB: High-speed transfer between embedded hardware and a computer.
3. SPI/SD card: Data is retrieved from removable storage.
4. I²C: Used to read data from sensors and EEPROMs.
5. Network/Wireless: Data can be transferred remotely using appropriate communication hardware.

Typical Retrieval Flow

Sensor Data → Storage/Data Logger → Communication Interface → Computer → Analysis Software

Plotting Techniques

1. Time-Domain Plot

Plots signal amplitude against time.

Useful for temperature, heart rate, vibration and other time-varying signals.

2. XY Plot

Plots one measured variable against another, such as pressure versus temperature.

3. Frequency Spectrum

Uses techniques such as the Fast Fourier Transform (FFT) to show signal magnitude versus frequency.

Useful for vibration and periodic-signal analysis.

4. Trend Plot

Shows long-term changes such as temperature over several hours or days.

Typical Software Workflow

1. Connect to the data logger.
2. Retrieve raw samples.
3. Parse the data format.
4. Add timestamps/channel information.
5. Apply calibration and units.
6. Remove invalid values if required.
7. Plot the data.
8. Save the graph or processed dataset.

Example

For vibration data, the time-domain graph can show transient events, while an FFT plot can identify dominant vibration frequencies.

Conclusion

Data retrieval transfers stored measurements into an analysis environment, while plotting converts numerical data into visual information that makes trends, abnormalities and frequency components easier to identify.