On my sailboat I have 2 150Khz depth sounders, each on so positioned that it points straight down when the boat is leaning on the appropriate side.
Currently I have a manual switch to connect the coax cable from the depthsounder that I want to a single coax that goes to a Actidyne DST-2 unit that translates the analog data to NMEA 0183 data that is being used in the navigation software.
Now I'm considering installing an Arduino board to translate some data from the analog gauges of my old (1978) Volvo Penta MD7A engine to NMEA0183 data to be used in OpenCPN as well.
So I suppose it would be possible to detect the tilt of the boat using a 3-axis-sensor, and a relay of some kind would needed to handle the 12v@50amp current needed for the depth sounder.
But is there a component that could handle switching between those 2 wires so that the Arduino could select the correct one for me, instead of having to 'throw the switch' manually, as well as handle the currents needed for this problem?
Sincerely,
Jurgen
Are you sure about that 12v@50 amps? All the depth sounders I have played with use much less than an amp or two typically (and work quite well). Unless you are mapping the Challenger Deep, I can't see 50 amps being required for a depth sounder. Makes a big difference on you you switch them. If you were going to control them with a processor, I would (especially in a sailboat that is continuously moving) "average" the input before making decision to switch - especially in light wind or when you are coming about, you will probably get multiple swings each way and I can't see that being good for a depth sounder.
If it's really 50A, then a 60A relay could be used.
Probably want to make sure one side is disconnected before the other side is connected.
Will need a transistor to switch the coil current on & off. Don't forget a diode across the coil contacts.
12V 50W = 600W. Maybe cooking the fish on the way up?
My mistake:
Nasa 150Khz Depth Transducer
Replacement depth transducer with 7m of cable.
• Supply voltage: 12V DC
• Power consumption: nominal 120mA
• Power output: 100w pulse
• Operating frequency: nominal 150kHz
Guess I was confusing with the 600W anchor winch, been a rough last few days ....
CrossRoads:
If it's really 50A, then a 60A relay could be used.
2-1393302-2 TE Connectivity AMP Connectors | Relays | DigiKey
Probably want to make sure one side is disconnected before the other side is connected.
Will need a transistor to switch the coil current on & off. Don't forget a diode across the coil contacts.
12V 50W = 600W. Maybe cooking the fish on the way up?
So let me rephrase that to make sure that I understand you correctly:
You are suggesting to connect both cables to the DST-2 and use a relay on both one, and standard have both depthsounders disconnected and close he circuit for the one you want, and when switching disconnect both, and reconnect the other one.
As for power rating= 100W pulse / 12 +10% = 10A one?
And about switching, most of the time it will be obvious on what side one is and it isn't going to switch all the time. The only exception would be when 'running' or possible 'broad reaching', and as the boat is basically level in those case, either transducer would be equally 'wrong' and one doesn't simply doesn't benefit from switching so don't. So one could say don't switch until the tilt is at least 5 or 10 or .. (experimental) degrees on the otherside.
Sincerely,
Jurgen
PS: Cooking the fish on the way up might be a good idea, saves work in the galley.
"You are suggesting to connect both cables to the DST-2 and use a relay on both one, and standard have both depthsounders disconnected and close he circuit for the one you want, and when switching disconnect both, and reconnect the other one."
Yes.
Current rating - whatever is you need plus some margin.
When to switch - what you describe sounds feasible. Hard to picture how much lean 5-10 degrees is.
Ah, you are making a mistake trying to work backwards from the power rating into the transducer to get the current. Those 100w (or 600w or whatever) ratings apply to the very short burst of energy fed into the transducer, not a continuous power rating (look at the fuse on the depth sounder - I bet it is somewhere in the neighborhood of 3A or so). The short burst of energy into the transducer is handled by the capacitors in the depth sounder - the average current used is much less than the quoted "power".
gpsmikey:
Ah, you are making a mistake trying to work backwards from the power rating into the transducer to get the current. Those 100w (or 600w or whatever) ratings apply to the very short burst of energy fed into the transducer, not a continuous power rating (look at the fuse on the depth sounder - I bet it is somewhere in the neighborhood of 3A or so). The short burst of energy into the transducer is handled by the capacitors in the depth sounder - the average current used is much less than the quoted "power".
Thx GPS Mikey, for pointing that out.
I fear the fuse will be the standard 8A that came with philippi switch panels, and most of the electronics are grouped together on a single fuse/switch.
I know, the mess of the previous owner, and I'm still cleaning it up 
jurgen
Even the "standard 8A that came with it" indicates what I was talking about (that is a long ways from 50A). The users manual (if lost, check on-line) should indicate what fuse should be used - you can figure that is somewhat over what the actual draw is by at least 50%, probably more.