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Healthcare

Case Study: Mission-Critical Intra-Hospital Communication System


Sector: Healthcare / Mission-Critical Systems


Nature of Project:


BFO Systems developed a high-reliability intra-hospital communication system designed for secure speech transmission, room identification, and ‘follow-the-light’ navigation during emergency Code Blue events. Given the mission-critical nature of the system, proven industrial and military-grade components were required, ensuring absolute reliability and robustness.


Tech Stack Used:

  • Microcontroller: Microchip PIC17C756     (EPROM-based for maximum stability)

  • Memory:

    • 16KB of program memory

    • 902 bytes of RAM

    • External EEPROM for non-critical event logging

  • Displays & Indicators:

    • Static LCD alphanumeric displays

    • LED-based directional guidance system

  • Audio Processing:

    • Manchester encoding & decoding of ADPCM data handled by FPGAs

    • PWM-driven sirens & system sounds, with lookup tables stored in program memory

  • Communication Protocol: RS-485      high-resilience network for inter-server data sharing


Major Challenge Overcome:


Memory Constraints & Real-Time Processing in a Mission-Critical System


The system’s microcontroller, PIC17C756, had just 16KB of program memory and 902 bytes of RAM, yet needed to handle real-time speech encoding, emergency alerts, and directional light guidance across large hospital corridors.

To ensure reliable operation within these constraints, BFO Systems:

  • Wrote all code in assembly for      precise timing control and memory efficiency.

  • Eliminated dynamic memory allocation to prevent unpredictable behaviour.

  • Stored all mission-critical string tables in program memory, ensuring emergency instructions were always accessible.

  • Used lookup tables in program      memory for PWM-driven sirens and system sounds, avoiding      unnecessary computations.

Additionally, the system supported 64 LED guidance nodes per server, which could be daisy-chained via RS-485, allowing hospitals to expand the system across wards and buildings while maintaining resilience.


Outcome:


BFO Systems delivered a stable, ultra-reliable hospital emergency communication system that provided:

· Secure speech transmission without degradation.

· Instant directional lighting guidance for emergency responders.

· Scalable hospital-wide networking using RS-485.

· Resilient mission-critical performance, even in power-loss scenarios.


This system dramatically improved response times during Code Blue events, ensuring medical teams could quickly navigate to critical situations without delays or confusion.

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