I have revised my schematic for the wireless AIS/chartplotter once again. I decided it would be a good safety feature to be able to monitor the coordinates that the
GPS dongle was sending to the
radio to make sure there's a reliable fix. So I added a second Bluetooth converter to feed the
GPS readings wirelessly back to the
chartplotter. (The prior design had the
chartplotter receiving
GPS by tethering to my
Garmin Oregon 400c.) Now I have full redundancy - the Oregon and the
GPS/AIS/DSC/Autopilot/Bluetooth/Netbook
chartplotter system are each separate standalone systems. Thanks to the wireless connection, the netbook
chartplotter can be located anywhere on the boat - in the cockpit (I have a RAM Mount to put in on my pedestal guard) or down in the cabin if weather is poor. Either way, all the information goes to/from it wirelessly via Bluetooth. If I turn the netbook off (or its battery runs dead), the
radio still gets GPS signals directly from the GPS dongle.
I picked up a small surface-mount network box to serve as the central connecting point for everything. I am going to use RJ45 connectors to terminate all the wires, and daisy-chain RJ45 receptacles inside the box. I'll also mount a couple of DB9 receptacles in the box, so the Bluetooth dongles will plug into the box directly. The whole thing runs off a 5v supply from a USB power adapter, and draws under 270 mA @ 5v. I've mapped out which pins on the RJ45 bus will correspond to each wire. Here's the schematic and wiring plan: