Friday, 16 August 2013

Onboard Navigation PC design and install.

It's been a long time since our last post. We've been sailing every weekend and enjoying the boat as a family. There is a lot to catch up on and I'll endeavour to get more posts done in the near future.

Our existing navigation systems on the boat are in reasonable condition but the cost of obtaining charts for our intended cruising area and spares for them is prohibitive. Our current installed equipment is:
  • Raymarine pathfinder 70C with radar
  • B&G network chart plotter, autopilot and instruments
That means 2 sets of charts in order to be able to use the two systems properly and of course they are not compatible. The unfortunate part is that they dont communicate with each other and have propietry communications protocol this makes getting information out of them a little more complicated but doable.

Knowing that the expected lifespan of the above components is well past due. I can either upgrade them to their modern day equivalents or alternatively convert the Boat to a PC based Navigation solution and slowly convert the systems to nmea 2000 compliant sensors. In the long run this will be more cost effective and actually give a more user friendly system. I'll even be able to replicate what is on the nav pc screen on an iPad or similar tablet.

It's a bit of challenge to design my own system for the boat. I have done this many times for my own personal pc over the years but have decided that it would be most effective to use one of the commercially available low power pc's in the market. If i want to modify it at a later date I can.

Through research and past experience I am leaning towards the Asus Eeebox pc. The chosen model is the EB1007p and runs off a miserly 15 watts in low power mode. It could be lowered even further by replacing the hard disk with a solid state drive, but this will be done at a later date if required. The pc requires 19v dc power but the boat system is a nominal 12v system, so a method of increasing the voltage is required one solution is a dc to dc converter like the one in this link.

http://www.ebay.com.au/itm/390634246780?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

One of the above units has been installed behind the nav panel and provides 19v dc for the pc. The pc works well as a nav computer but the refresh of maps and swapping between program windows is a little slower than your average desktop. I'm happy with the slower performance given the miserly power consumption. All up and including the 22" led monitor the power consumption in 3.1 amps. We are running opencpn as our navigation software.



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