Homebuilt Rov Forum

Exploring the Hobby of Building your own ROV - Imagine, Create, Inspire.
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 Post subject: Neub questions
PostPosted: Dec 26th, 2015, 7:06 pm 
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Joined: Nov 24th, 2015, 4:22 am
Posts: 7
Hi The name is Rich, I am 72 years young and retired Army SSG and Boeing Machinist/NC programmer. I am also a NAUI masterdiver/photographer with well over 2000 dives but I am now grounded and can't dive anymore. Thus I am planning to build and ROV to continue my diving/photography.

So now that I am introduced I need some help getting through making a control system. My concept is to have the power for the bilge pump motors on board and the controls/monitor on shore. But I need some of you geniuses on the electronics side help me interface the two. Somewhere in the maze of the internet I found a video on doing this with an Arduino and motor drive shield but I can not find it again. I purchased the arduino UNO R3, a Sainsmart motor shield for 4 motors and 2 servos plus a sainsmart 4 relay card to be able to use the 12v motors but that is about the limit of my knowledge. Now I either need to pick up a mentor here or someone to aim me in the direction of some videos on the subject. I plan to us a cat5 cable as my tether and I do have both a laptop and an android tablet for programming.

Any help or suggestions will be received with joy and thanks


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 Post subject: Re: Neub questions
PostPosted: Dec 27th, 2015, 11:19 am 
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Joined: Dec 18th, 2012, 5:52 pm
Posts: 183
Location: Netherlands
On the site of Arduino they have great starter sketches to begin with Arduino and servos. From there search the web for programs using the motor shield you purchased.


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 Post subject: Re: Neub questions
PostPosted: Dec 27th, 2015, 12:44 pm 
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Joined: Nov 16th, 2013, 3:11 pm
Posts: 190
Location: Ft. Lauderdale FL
@Hipshot131,
If you have the money and the time I would buy better components for building your ROV especially if you want to dive to over a 100 ft.
Therefore you might want to consider ROV products from Blue Robotics (https://www.bluerobotics.com/store/).

They plan to offer control systems from the simple to the more complex in the coming year so you do not have to roll your own. Also, the operating firmware will be Open Source.

You can read about my ROV Project that uses Blue Robotics components here: viewtopic.php?f=18&t=1707

I bought BR Thrusters and WTCs, but I built my own chassis out of 1/2" thick HDPE.
Regards,
SSN626B/TCIII


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 Post subject: Re: Neub questions
PostPosted: Dec 27th, 2015, 4:50 pm 
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Joined: Feb 28th, 2013, 6:01 pm
Posts: 383
Location: Australia
Hi Rich. Just reading "N.C. Machinist" suggests to me that you have much in your favour for building an Arduino-based ROV.

Motors: Personally i would say that brushless motors and controllers (ESCs) are the go, provided you have a lathe handy to make oil-filled pressure-compensated motor housings.

Control and sensors: An Arduino topside and below, each connected to an RS485 converter board. This will give you 2-way comms over a single pair of wires. Camera will need it's own cable, either another pair or coaxial.

Connect a couple of joysticks to the Arduino analog inputs, read these with some simple code (it gets simple pretty quickly) and send the numbers down the cable. Below use the standard Arduino "servo" function to send control signals from the ROV's Arduino to the ESCs. ESCs accept the same control signal as regular model aircraft servos.

After that you can send data back up the line such as depth and heading and display that, on an LCD on your control box, OSD, HUD, whatever.

Having already obtained the brush-type motor controller, you have a good place to start. I would suggest getting a joystick or even just a single potentiometer (2-axis analog joysticks are simply 2 pots, X and Y) and get that controlling motor speed and direction with what you have. If you do go to brushless then the code gets simpler.

Hope that is of some help,
Ross


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 Post subject: Re: Neub questions
PostPosted: Dec 27th, 2015, 8:25 pm 
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Joined: Nov 24th, 2015, 4:22 am
Posts: 7
SSN626B wrote:
@Hipshot131,
If you have the money and the time I would buy better components for building your ROV especially if you want to dive to over a 100 ft.
Therefore you might want to consider ROV products from Blue Robotics (https://www.bluerobotics.com/store/).

They plan to offer control systems from the simple to the more complex in the coming year so you do not have to roll your own. Also, the operating firmware will be Open Source.

You can read about my ROV Project that uses Blue Robotics components here: viewtopic.php?f=18&t=1707

I bought BR Thrusters and WTCs, but I built my own chassis out of 1/2" thick HDPE.
Regards,
SSN626B/TCIII

Problem is I am on a very tight budget. If I have that kind on money I would just go with their kit and call it good! The other problem is their stuff at the moment is mostly vaporware. (promised for some future date)


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 Post subject: Re: Neub questions
PostPosted: Dec 27th, 2015, 8:39 pm 
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Joined: Nov 24th, 2015, 4:22 am
Posts: 7
@rossrov
Thanks Ross, sounds like you might have the knowledge that I need or at least point me in the right direction. I am not going brushless because my work will be 100% salt water and I am very familiar with what saltwater does to any electronics it comes in touch with and I also know, the hard way what happens to the bearings on brushless motors with any sort of exposure to saltwater. I have the pumps already and already have them cut down an ready to mount.

I have always been the hands on type so I'm not afraid to jump in. In addition to the NC experience I am a toolmaker and I do have a lathe and a mill. In fact I build canister dive lights that are quite popular and waterproof to 300 ft. I am not interested in much deeper than recreational dive depth, 130ft. for the ROV but I plan on using a HD level camera so that I can continue my critter photography. In case anyone might be interested my photo site is underthesound.com


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 Post subject: Re: Neub questions
PostPosted: Dec 28th, 2015, 4:43 pm 
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Joined: Feb 28th, 2013, 6:01 pm
Posts: 383
Location: Australia
Checked out your site. I like the look of those enclosures, and that 5 amp hour battery. Simpler than Li-Po. Make sure that the current rating of your motor drive board is up to running whatever pump motors you have. If not high enough, maybe use lower voltage supply to reduce the current, or use some smaller motors while getting your code working.


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 Post subject: Re: Neub questions
PostPosted: Dec 28th, 2015, 6:52 pm 
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Joined: Nov 24th, 2015, 4:22 am
Posts: 7
rossrov wrote:
Checked out your site. I like the look of those enclosures, and that 5 amp hour battery. Simpler than Li-Po. Make sure that the current rating of your motor drive board is up to running whatever pump motors you have. If not high enough, maybe use lower voltage supply to reduce the current, or use some smaller motors while getting your code working.


Thanks those are for my lights and they are tested to 300 ft. To small for a power source but similar to what I will do for the ROV just bigger. Not really worried about lighting my dive lights are more than adequate.

Just got to figure out the controls system. Wish I could find that youtube video again!


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 Post subject: Re: Neub questions
PostPosted: Dec 29th, 2015, 2:07 pm 
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Joined: Nov 16th, 2013, 3:11 pm
Posts: 190
Location: Ft. Lauderdale FL
@Hipshot131,
This post will give you an idea of using an Arduino to control your ROV: http://www.homebuiltrovs.com/rovforum/viewtopic.php?f=15&t=1293

You can find Nick's website here: https://sites.google.com/site/underwaterrovproject/

I have his two board ROV control solution which he unfortunately no longer sells.

Also, I believe that you will find that the rubber seals on the bilge pumps really start to tighten up on the motor shaft the deeper you go which will greatly increase the motor current.

Regards,
SSN626B/TCIII


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 Post subject: Re: Neub questions
PostPosted: Dec 29th, 2015, 5:52 pm 
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Joined: Feb 28th, 2013, 6:01 pm
Posts: 383
Location: Australia
Hi SSN626B and Rich. Good point about the seals, though I must say I've never used bilge pump cartridges, just brushless motors. Nick's code may well be very good, but for those who want to learn for themselves, and start with something more basic, I don't think it is too difficult to send 4 numbers down a pair of wires to control 4 motors. Granted, some hours or days involved in learning.
Only 4 or 5 pieces of code to put together:
https://www.arduino.cc/en/Reference/AnalogRead
https://www.arduino.cc/en/Serial/Write
https://www.arduino.cc/en/Serial/Read
https://www.arduino.cc/en/Tutorial/Knob for servo (or ESC!!) control from pot, probably the best place to start

Odd thing happened yesterday. I visited my local electronics store wanting to buy among other things a 5 amp or greater DC brush motor controller. They did not have one in stock, so I ended up buying one of those L293 boards for testing the project with a smaller motor. I also bought a $5 DPDT relay. The relay can be used in conjunction with a $2 power FET to make a very simple higher current reversible speed control.

I "found" some example code for the L293 shield. http://playground.arduino.cc/Main/AdafruitMotorShield. Will have a look at that today. The shield is not powerful enough for bilge pump motors, but apparently more chips can be piggybacked to up the current. Also, it may be useful to drive some FETs to give much higher output current.

Hobbyking and others sell cheap brush motor ESCs. These are good for Ni-MH/Ni-Cad RC car pack voltages, but 12 volt versions seem harder to find.


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