COnclusion

1. NEC (NFPA 70) - National Electrical Code Application: As previously mentioned, the NEC will serve as the baseline code for electrical safety, guiding the installation, wiring, grounding, and circuit protection of the Arduino, MP3 Player shield, and compression driver components. This ensures safe and reliable power distribution and proper handling of high-power connections, especially for the compression driver. 

2. IEEE 802.3 - Ethernet Standard Description: IEEE 802.3 outlines the Ethernet standards, particularly useful for defining networking and data communication protocols. Application: While Ethernet may not directly apply to Arduino, the communication principles outlined in IEEE 802.3 can help implement stable UART-based communication. This can ensure effective control and data transfer between the Arduino microcontroller and MP3 Player shield, avoiding interference and ensuring data integrity. 

3. IEC 60906-2:2011 - Plugs and Socket Outlets up to 20A/125V AC Description: IEC 60906-2 provides standards for plug and socket outlets, focusing on safe electrical interfaces for low-voltage AC applications. Application: This standard is applicable when connecting the train horn's power supply to AC sources. It ensures that the plug and outlet configurations used comply with international safety standards, minimizing the risk of electric shock and ensuring compatibility with standard power outlets. 

4. Universal Synchronous/Asynchronous Receiver/Transmitter (USART) Standard Description: USART is a protocol for serial communication that supports synchronous and asynchronous modes, allowing reliable data exchange between devices. Application: USART principles will guide the UART communication setup between the Arduino board and MP3 Player shield. Implementing USART enables smooth control of audio playback, essential for timing and reliability in the horn’s operation. 

5. IEC 62368-1 - Audio/Video, Information, and Communication Technology Equipment Safety Description: This standard focuses on safety requirements for audio, video, and information technology equipment, considering risks like electrical shock, fire, and mechanical injury. Application: Relevant for the MP3 Player shield and audio output, IEC 62368-1 helps in managing potential hazards associated with audio amplification and playback in the train horn system. Adhering to this standard can prevent overheating, ensuring a safe and effective audio system.

6. ISO/IEC 9899:2018 - Standard C Programming Language Description: This is the standard for the C programming language, widely used for embedded system programming. Application: Coding the Arduino in C according to ISO/IEC 9899:2018 ensures that programming practices are standard-compliant, supporting clear and efficient code for controlling the horn’s audio signals and timing. 

7.  IEEE 1474 - Performance and functional requirements for a communications-based train control (CBTC) system are established in this standard. A CBTC system is a continuous, automatic train control system utilizing high-resolution train location determination, independent of track circuits; continuous, high-capacity, bidirectional train-to-wayside data communications; and train-borne and wayside processors capable of implementing automatic train protection (ATP) functions, as well as optional automatic train operation (ATO) and automatic train supervision (ATS) functions. In addition to CBTC functional requirements, this standard also defines headway criteria, system safety criteria, and system availability criteria for a CBTC system. This standard is applicable to the full range of transit applications including automated people movers. This standard establishes a set of performance and functional requirements necessary for enhancing performance, availability, operations, and train protection using a CBTC System. 

Final Cost of Prototype: $450.16

We would be able to significantly reduce this price by choosing a more appropriate housing option for the horns and also choosing a more cost-friendly horn-cone option. 

• Adafruit

• DS18

• IEEE Codes and Standards

• Federal Railroad Administration