Turning up the safety

A new low-cost digital noise monitoring system is helping improve hearing protection awareness in Navy training environments, while demonstrating what can be achieved through local innovation.

The project began following a noise-level report for the TA-ENG, MT Fabrication Workshop, which identified significant variations in noise levels. This meant students could require different levels of hearing protection depending on whether they were listening to an instructor or undertaking practical work.

Following the report, Deputy Director Training Authority Engineering CMDR Jason Grivas asked Centre for Innovation – South (CFI-S) Manager CPO Allan Winning whether a digital noise sign could be developed to meet the requirement.

Relevant Defence guidance, including SafetyMan and AS/NZS 1269.1:2005, was reviewed during the design process. The signage was developed in accordance with AS 1319-1994, with the system designed so the appropriate noise-level warning could be seen throughout the workshop.

A Raspberry Pi Zero was selected as the processing platform because of its availability, specifications and low cost, while a DF Robot sound sensor was chosen for its reliability, accuracy and available design information.

CPO Winning used ChatGPT to assist with developing the Python software, which underwent several revisions and practical testing.

Further development introduced fault logging and a calibration mode, allowing the system to be checked against a calibrated noise-level meter.

The system's housing was designed and manufactured using CFI-S 3D printers. It operates as a plug-and-play system, requiring no user input during normal operation, apart from optional calibration checks.

“This system automatically allows those in the area to be aware of the current noise hazard and select the correct PPE. For areas with varying noise levels, this takes away the guess work and ensures everyone is appropriately covered,” CPO Winning said.

The project also focuses on value for money and reuse. Existing monitors that would otherwise be sent for disposal can be repurposed as displays, with the complete system costing less than $180 to produce.

Navy now owns the designs for all elements of the system, allowing the solution to be reproduced for other areas where noise levels vary. The CFI-S retains the design data and can support areas wishing to implement the system.

The result is a practical, low-cost solution that combines readily available technology, local manufacturing and software development to provide clear, real-time awareness of changing noise levels.