Internet of Boat

Hi Friends…

I have an older sailboat on a mooring.(Shoal Bay NSW) that I want to do some remote monitoring on. I have 350W and 200AH house battery though I think the battery struggling under load(fridge etc).

I want to be able to know when the bilge pump goes on, make sure that its still on its mooring and potentially be able to turn on the 12v fridge and access some instrument data.

I have already bought a 12v Openwrt 4g router that’s working ok (not on the boat yet). Its one designed for cars and buses based on a Mediatek MT7620A chip.

I am new to the IOT having played around with Rasberry Pi a bit. I have just bought the Omega 2 (still awaiting delivery) and initially want to monitor get notification when the bilge is running. This runs on a float switch and has been temperamental hence why I want to monitor it. Ive just bought the Gravity current monitor but know the Omega 2 doesn’t have any where I can read a analog voltage but just want to detect if there is current running through the circuit not so how much. I know I might need to use a regulator to make sure the voltage from the gravity current monitor is acceptable. I’m a noob to all this. Any advice would be great.

Id also like to look at remote bird deterrents(they poop everywhere).

I also may want to update some of my switching to smarter switching (Mosfets, 12v Automotive relays?) on some of my lower current devices.

All the systems are 12v.

Any advice appreciated - Rod

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Hi Rod,

The internet of things can be an exciting and sometimes complicated project to take on. I recommend taking it one part at a time and building on what you already have working. That said, I have a bit of advice to get you started.

For current monitoring you can get a current monitor like this one:

If the bilge pump draws less than 5A then you can use this to detect when the pump is running by connecting it to a Microcontroller. I’m not sure how you would interface with the router that you have, maybe @chris will know more. I would personally choose something like a pycom board for this sort of application.

As far a switches. I would recommend 12v relays since they won’t have “leakage”.

For bird deterrant, Maybe make something that makes a loud noise when motion is detected, or spins a motor with something refective.

Let us know how it goes!

Thanks I will start slow. I’ll just use the router like a normal rounder as a gateway to the internet to a cloud service. Really what I want is to detect when the float switch is activated. Could I run a parallel circuit with say a 2000 ohm resistor and measure a voltage after the resistor. Which will indicate the switch is activated and the bulge pump should be running. I’ll give it a test on the bench and see how it goes. Thanks for your feedback. Yes 12v automotive relays probably the way to go although they do draw a fair bit of current when active. When I’m not running the motor this could be a significant amount if I have a few.

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You could use latching relays. They change position with an electrical pulse but then stay in that position. There is just the risk that when they fail they could fail in the ON position.

Electricity will always follow the path of least resistance. My gut feeling is that if you make a parallel circuit with a big resistor, the current will just not pass through it. Something like this would work great:

You connect it in line to your pump, it outputs an analog voltage proportional to the current flowing through it that you can use as your indicator. Its essentially the same as the other one I suggested except this one can handle more amps.

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