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marcobergman / remote_pilot

Raspberry-based (wired) remote control sending out Seatalk commands for a Raymarine tiller pilot, or custom commands for a TinyPilot / ray.py interface.
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Raspberry Pi connection to ST tiller pilot #1

Closed spagnuolocarmine closed 4 years ago

spagnuolocarmine commented 4 years ago

First of all, thank you for your interesting work.

I am not an expert in electronics stuff, but I would like to the same project.

Could you give some information about the connection between the Pi and the ST. I understand that the ST connection has 3 cable Yellow (data seatalk), Red (12v), Black (GND).. is it possible to connect the Pi to the ST directly on this cable?

I am sorry for these questions, that maybe can be seen as not good ones.

Thank you in advance

marcobergman commented 4 years ago

Hi Carmine, thank you for your question, and it's good you ask. I understand your want to know whether you can connect the pi output directly to the yellow seatalk connection. This is not possible; you are likely to damage your pi output. The seatalk input is normally 'pulled up' to +12V, a pi output is limited to dealing with 3.3 volts only.

Also, the red cable of the seatalk cabling normally carries +12 volts, whereas the PI would require no more than 5V.

So you would need a separate 5 volt power supply to feed your pi, and you would need at least the 'level shifter' circuit as given by the ascii art in the code. This is not difficult to make; any first year electronics student can cook it up.

You ought to know that I don't follow the seatalk protocol strictly, which is quite difficult to do, as it would require checking for collisions on the seatalk line while you are sending yourself. Not doing so can result in collisions, meaning, lost data. For my purposes this is not a real problem; I have this in use on my boat.

Kind regards,

/Marco Bergman

On Tue, Jan 28, 2020 at 3:39 PM Carmine Spagnuolo notifications@github.com wrote:

Closed #1 https://github.com/marcobergman/remote_pilot/issues/1.

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spagnuolocarmine commented 4 years ago

Really thank you for your quick replay.

best