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jfish System Integration - Networking Guidelines

This is a placeholder for a description of the networking protocol that jfish devices will use to communicate in order to extend their function. The details and choices for our inter-device networking should be discussed on the developers mailing list - if you want to help with this, please jump in!

We need to decide on both the bus architecture/type and the protocol used for communication.

Networking purpose

  • To allow devices to share information/sensor data with each other. eg. The ECG sharing QRS-complex timing with the pulse oximeter to enhance movement-artifact reduction.
  • To allow devices to share sensor data with a computer. Thus the data is all available in a central location, in an open format, viewable on a single screen (= anaesthetic workstation) and further enhanced by the inherent capabilities of the computer (ie. networking, data storing, communication, printing, web-cams, etc. as available)
  • It is important that the presence of network-capability does not detract from the functionality of the devices when they are used as isolated monitors. While networked devices allow huge leaps in functionality, networking is secondary in priority to the primary goal of designing reliable, safe and accurate monitors.

Networking goals

  • Simple implementation
  • Low-power consumption
  • Auto-configuring and auto-detection of devices
  • We don’t need particularly high data rates, as the ADC and initial DSP will be done in each device.

Roadmap

  • Finalisation of the networking details is not needed for the initial production-ready devices, but the hardware aspects (ie. bus lines, schematics, etc.) do need to be decided so that we can upgrade devices to network-capability via firmware updates alone.
  • Will be most relevant when the jfish pulse oximeter and ECG are finished.

Bus options

  • 1-Wire designed by Dallas Semiconductor. – Probably the best choice due to it’s low cost and power consumption. Is this available on Atmel microprocessors?
  • 1²C designed by Phillips.
  • Bluetooth or ZigBee wireless short-range networking. Although this appears at first thought likely to be more expensive than wired connections, the falling costs of bluetooth chipsets (~$5 in volume) may in fact make this cheaper than the hardware needed for wired connections. ‘Hardware’ (cables, plugs, etc.) makes up a significant cost of the individual devices. The short-range of Bluetooth would be the most appropriate for the needs of device interfacing.

Protocol details

To be documented as it develops...

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