Zigbee
Some new hardware
I realized it would be better to have a desent board instead of loose wires so I soldered a board with a detachable connection to the Garmin plotter. There is also room for the small Zigbee module. The serial routines has been running well when they have been on their own. Rigth now I have serious problems to get them to run together.
The somewhat organized board
The deep keel
I found a new boat for sale, but I don't think I can afford it.
And it would probably not be able to reach the small beatiful bays I
use to visit because of its deep keel.
I found a new boat
Coolterm for Mac and debug via USB
I am getting used to debugging true the old printf method.
I am using the Coolterm for Mac wich turned out to be a real good tool especially
since it can show my AIVDM strings in hex.
Getting closer
After some new AIS strings I managed to get a ship into the Garmin display.
The Garmin plotter seems to timeout rather quickly after some 2 seconds.
Next I plan to capture one of the strings coming from the plotter to get the longitude and latitude and resend it back as an AIS close to my boat.
Ship in Garmin display
Ais to Garmin
After a few attempts I managed to get the Garmin to accept my Ais messages.
I have not decided where to put the measurement info or if I should use another kind of message. There are quite a lot of them.
Going for some duplex
Imade some more temporary solder works to interface the Garmin. I will probably have to read through some more papers before I make a first attempt to send something down my "homebrew" line.
both ways
A simple transistor
A simple bc337 and two 2k resitors made everything work. Before that a had a go with a Maxim 222 Rs232 converter with no sucess. I hope the solution will work in the other direction towards the Garmin.
bc337
What will be next
It seems I made yet another mistake with the electrical interface to Garmin 620.Next time I will try with a balanced driver.Using a normal TTL driver made it go into self oscillation after a short while.
In need of a decoppling capacitor?
A minor step on the way is to get the inverter working, it seems like failed at the first try. I do get the NMEA sentences from the navigator but the output looks at times awful. Perhaps it is only a decoppling capacitor I need.
NMEA sentences
A poor output
temporary hardware
Some tiny soldering
I will interface the Garmin with ttl levels, so I needed to invert the signal.
Instead of going for the old 74 series I tried the tiny one logic circuit.
one gate logic
