This project in making is about investigating different methods for logging data in the yacht from the existing instruments and installation with the addition of a few simple sensors.

The plan is to collect the following information

• Wind speed and direction from Raymarine ST40 Wind Instrument
• Depth and log from Raymarine ST40 Bidata Instrument
• Voltage at engine and usage batteries
• Outside temperature

One challenge is to understand and capture commands from the old Raymarine instruments that use the proprietary Seatalk protocol which Raymarine refuse to document. Fortunately some good engineers have done a nice job with reverse engineering in order to clarify how it works as seen here.

Another useful information on board is battery status. The health condition of the batteries can  be monitored by reading the current voltage and compare to the ideal voltage of 12,6 volts. While engine is runnning the voltage increase to 13,7-14,7 volts.