Meteor candidate observations from automated weather camera sampling in VBA

Automated sampling of webcam imaging was investigated as a means of meteor data collection. A sampling system was developed in Excel with Visual Basic for Applications (VBA), the scripting language built into Microsoft's Office suite.

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Figure 1. Sampling webcams managed by Airservices Australia on Norfolk Island.

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Table of Contents

• Key Files
• Software Requirements
• Quality Assurance
• Getting Started
• Acknowledgements
• References

Key Files

File	Notes
src/automated-webcam-sampler.xlsm	Macro-enabled Excel workbook.
src/webcam-sampler.bas	VBA module.

The Excel workbook runs a standalone automated webcam sampler. Its constituent VBA module, WebcamSampler.bas, has also been provided as separate file for a) easy code review outside Excel and b) importing into another Excel workbook, if desired.

Software Requirements

• Excel (Windows version).

Quality Assurance

The webcam sampler has been tested with Excel, version 2508, on Windows 11.

Getting Started

Sampler Configuration

The webcam sampler has default settings for target webcams, sampling cadence, sampling period, download directory, etc. These should be configured in VBA to meet your needs prior to executing the sampler. A modest, not advanced, level of VBA knowledge is needed for this configuration.

Execution Options

Ensure VBA macro execution is enabled in Excel.

Additionally, ensure Windows isn't also blocking the workbook's macros. To resolve this, right click on the file to open the file's Properties. Go to the General tab, Security section and select the Unblock checkbox.

Once complete, there are three main ways to execute the sampler.

1. Macro Button

The single Excel worksheet features a "Take Shots" button at the top left of the worksheet that will execute the sampler.

2. VBA Editor

The DownloadFileAPI function of the VBA code will execute webcam sampling. This can be triggered from Excel's VBA editor. The VBA editor can be opened by selecting Developer, Visual Basic from the Excel ribbon. If the Developer option isn't visible in the Excel ribbon, it can be added by selecting File, Options, Customize Ribbon from the Excel main menu. (Excel version 2508 menu options.)

3. Imported Module

To execute the webcam sampler from another Excel workbook, a VBA module, WebcamSampler.bas, is available for import and execution. The sampler configuration options will still need to be customised to meet your sampling needs.

Acknowledgements

This work used publicly-accessible infrastructure managed by the Australian government's Bureau of Meteorology and Airservices Australia.

References

1. T. N. Stenborg, "Meteor candidate observations from automated weather camera sampling in VBA", in Proc. International Meteor Conf., U. Pajer, J. Rendtel, M. Gyssens and C. Verbeeck, Eds., Bollmannsruh, Germany, Oct. 3–6, 2019, pp. 189–190.
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