My lively sense of humour!
Two failings with version two of the diy yacht navigation system. The AIS (Automatic Identification System) for ships hasn't been working. I bought a second USB TV dongle after I suspected the first was unable to tune to the required radio frequency. Subsequently I took the 'blackbox" and home made antenna to the coast (three times) in an effort to receive a signal failing on each occasion. I finally realised the second cheap USB dongle might have the same issue as the first.
A third dongle was then purchased online. This one was more expensive and I was optimistic. Unfortunately this one was stolen in transit. All I received was the torn brown envelope. Fortunately the seller agreed to send a replacement.
The second is was the size of the case. Version 1 of the case proved to be too small. I then bought a larger case. That also proved to be too small. In the end I made a case from scrap plywood.
Front Panel (L-R) Volt/Amp meter Fan switch Fuse holder Main switch
Rear Panel
- Four USB ports
- Audio jack
- Ethernet port
- Two HDMI ports
- External sensor socket
- AIS antenna socket
- 12V input socket
In order to create some interior room for my shaky fat fingers and poor eyesight I've mounted the Raspberry Pi on a plinth
Every component or module that might fail has been mounted using Velcro. The idea is this should make replacement easier.
Inside
There are two outstanding tasks.
- I need to test the AIS module and confirm it can receive signals and display ship position data.
- I've ordered two optocouplers which need to be installed. One will be for the existing yacht depth sensor and the other is either a spare or for a second sensor (eg, anemometer).
Yes, the wiring does need to be tidied!
Grandson's yacht is old (1991) and the current depth sensor used the 'SeaTalk' communications data protocol. This was a propriety protocol developed by Raymarine. Eventually SeaTalk was replaced by a new protocol, NMEA0183. This has now be replaced with a canbus protocol NMEA2000.
The 'Blackbox' uses the NMEA0183 protocol and an optocoupler is required to convert the SeaTalk data to a NMEA0183 compatible format.
Hopefully the project is nearly finished.
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