Servers by jDrones

Ok this is going to sound weird... but it can work! Using Trolling Motors :)


(Adam Cropp) #1

Hello Everyone!

I am currently working on a very interesting build but I am stuck with part of the design and could really use your advice!

I am using a Pixhawk to steer a larger boat autonomously but instead of using small thrusters and ESCs (Blue Robotics) I am using two larger trolling motors activated with a 12V relay.
There is no rudder so steering is controlled via the motors. (Skid Steer)

My problem lies in how to control / wire this thing together?

I have lots of experience controlling motors with an ESC but how can I get the pixhawk to activate the relays as THROTTLE PORT & THROTTLE STBD.

Also, considering that I don’t actually have a throttle or speed control as such - only the ability to turn either the port or starboard motor on/off…

What settings would need to be changed to enable it to keep a course through the water?
or would the ardurover code just not handle these modifications to outputs?

I have done quite a bit of research online but I can’t seem to figure out the easiest way to make this work.

Surely, it can’t be too hard?
I am basically simplifying the autopilots controls to only two outputs. Forward Port & Forward Starboard.

Thanking you in advance for your great advice!

Adam


(Russ Jarvis) #2

Hi Adam

I’ve built a 2m skid steer boat that runs on Minn Kota trolling motors. Just cut out all the Minn Kota electronics and wire some ESCs to the motor power leads and Ardurover / Pixhawk will do the rest!

What motors are you wanting to use? Something that runs on a bus protocal system?


(Adam Cropp) #3

Hi Russ,

Thanks for the info mate…

  1. I would need two big 50A esc each to make that work… and I am also a
    little worried I might break the motor with unusual input…

  2. Is there anyway to just change a setting to make it work with the relays
    I have already? I don’t need to change speed…

  3. I am using 45lbs 12v striker trolling motors… the throttle switch /
    speed regulator looks like a simple mechanical type. No electronics inside
    whatsoever.

  4. Love to see some pics from your boat!

Adam


(Russ Jarvis) #4

Hi Adam

Just find out if your motors are brushed or brushless and buy a suitable ESC; there will be one out there. We’re using two 30lb thrust minn kotas that draw 30A peak each at 12v. We use a 40A ESC on each and it works great. Your boat is going to be spectacularly uncontrollable if you just use relays to turn your motors on and off! Can’t show any photos at the moment as the boat is for a client and is yet unreleased.

Good luck with it all!


(Adam Cropp) #5

Hey!

So I know the motors are brushed and I have a suitable (I hope - its very small) esc to use.

My problem is what to do with the two extra wires that are coming out of the motor shaft, surely I can’t just ignore these two wires like I have seen in some youtube videos. I have done a bit of research and can’t find a clear answer on how best to wire the 2 wire esc to the 4 wire trolling motor. I am kinda understanding why the extra two wires are there in theory but I still can’t work out how best to wire the whole thing up.

Since you have probably already encountered this problem any help would be greatly appreciated!

Thanks,
Adam


(jeffg) #6

Wire the black and Red (heavy gauge wires) to the ESC. I have used a Sabertooth and Syren ESC from Dimension Engineering. I cut or tie up the remaining three wires. They are used for the mechanical speed controller and not necessary for the ESC.

Also, use ESC that can handle more current than you think you need.


(Alex Alexs) #7

If you don’t want any speed control you can use an arduino uno or any dev board to trigger the relay upon receiving a pwm signal.

Something like 1800 Pwm input -> trigger a handy relay
1200 PWM input -> untrigger handy relay.

Do a schematic what you want to do the relays get a arduino board and i will make code for you to work.


(Alex Alexs) #8

Arduino board will get a pwm input from PX