New to Arduino, what should I get?

Anything to do with programing the Arduino Platform.
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NCUWI
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Joined: Nov 25th, 2011, 3:27 am

New to Arduino, what should I get?

Post by NCUWI »

I'm considering building a control and sensor system based on the Arduino. I've never used an Arduino before, from it looks like what I want is possible:

- RS485 comms with the surface
- Control 4 thrusters (brushless with RC style ESC's)
- Control 2 servos (RC style for pan/tilt)
- Display basic data (date, time, compass heading, depth) as a video overlay
- Use a PC topside for control

After a bit of google-fu last night and today I found all sorts of info, code samples, add-on shields, etc. so I suspect this won't be too difficult and I suspect other people here have already done this (or something very similar). Where should I start? What should I get?

Thanks!
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ArduROV
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Re: New to Arduino, what should I get?

Post by ArduROV »

My control-system is based on two Arduino Mega with a protoboards on it for the different "add-ons".
NCUWI wrote: - RS485 comms with the surface
For the RS485 you can use one of the hardware serials of the Mega and convert it with a small IC to RS485. I took the MAX490 for full duplex RS485.
NCUWI wrote: - Control 4 thrusters (brushless with RC style ESC's)
- Control 2 servos (RC style for pan/tilt)
The short answer is: Yes
You can use the analog.write funtion to generate a PWM-signal for the Servos and ESCs. The easier way is the servo libary. Another way is to use a Serial Servo Controller. I control my ESCs and servos with a SSC form Pololu. The SSC is controlling the Servos and the Arduino is free for other things.
NCUWI wrote:- Display basic data (date, time, compass heading, depth) as a video overlay
- Use a PC topside for control
Its no problem to use a small LCD display to show some data. I used the SerLCD of Sparkfun.
My control System is a "no PC solution" with just two Arduinos but I can optionally hook up a PC for datalogging and extended displaying of data. Mostly I dont use a PC because I dont want to risk damage of my laptop on a boat or the dock.
NCUWI
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Joined: Nov 25th, 2011, 3:27 am

Re: New to Arduino, what should I get?

Post by NCUWI »

For servo control, I have a Pololu Micro Serial Servo Controller ( https://www.pololu.com/product/207 ) that I will probably use. I found some example code on the internet that might help me get started.

For the OSD, I'm thinking of using something like this: http://www.hobbytronics.co.uk/max7456-o ... rd=max7456

And for compass I'm thinking of using this: https://www.sparkfun.com/products/12916 I know there are cheaper 3 axis compasses out there, but I have used this before and it worked very well.

I'm not sure which Arduino to get, but I'm leaning towards a Mega since it will give me the most flexibility.

Thoughts?
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ArduROV
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Re: New to Arduino, what should I get?

Post by ArduROV »

I use the same SSC. Its very easy to handle. If you need Arduino code, this is all you need for basic function:

Serial2.write(255); --- start byte
Serial2.write(3); --- channel (0-7)
Serial2.write(128); --- servo position value (0-254)


The compass is not the cheapest one but it might be a good way if you can effort 150$. Im tinkering with a MinIMU (https://www.pololu.com/product/1268) for my Autopilot but its not easy to kalibrate the sensor in the ROV and its not always pointing in the correct direction.
NCUWI
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Joined: Nov 25th, 2011, 3:27 am

Re: New to Arduino, what should I get?

Post by NCUWI »

@Ardurov - My hope is to have the Arduino in the ROV and use a Windows tablet topside. I want to talk to the Arduino using RS485 for servo/thruster control. For sensors (compass only for now) I want to use the compass and OSD shield I linked to. That way the sensor data is displayed on the video and doesn't need to be sent back up to my tablet. Any problems you can see with my plan?
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KR2_Diving
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Location: Currently: NW Suburbs of Chicago. Originally: NE Wisconsin

Re: New to Arduino, what should I get?

Post by KR2_Diving »

Hey NCUWI,
Sounds like you are on the right track!

I would HIGHLY recommend getting THIS BOOK.

It covers all the basics you need to get started with Arduino. I have a very well worn copy of my own that is never more than a few feet from me when I am working with my Arduino.

I, much like ArduROV, am building a PC free ROV run by Arduinos. At the moment, I have an Uno topside and a MEGA in the ROV. If you are looking to get started and practice with the Arduino, get an Uno! The price is right, and even if you decide later to upgrade to the MEGA, the UNO makes a great test board to try all your individual systems. (Servo Control, External Displays, OSD (on screen displays), compass, Coms, etc...)

I have even bought a second one just for testing sub-systems so I don't have to keep ripping apart the one I have set up for my ROV!

I have tried to put a lot of my notes onto the forum. You can check them out HERE.

Best of luck! As always, keep us all posted!

Happy Diving!

Ryan
"KR2_Diving"
Bindo
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Re: New to Arduino, what should I get?

Post by Bindo »

Hi NCUWI,

I think to use a pc/tablet, not only really complicates things, but also restricts your functionality greatly.

Getting the video overlay done subside is a smart move, however, the one of the main reasons i'm using instruments, is that if my video fails, i can still fly with instruments to (hopefully) get me home, so all my telemetry will be shown on 20x4 LCD screen which arduino can handle with relative ease!

I'm currently using 3x arduino's, probably a 4th to come, which will be my dedicated display controller, probably overkill, but i'm hoping it'll unload the topside controller


Currently my setup looks like this

Controller <TTL (full duplex direct serial)> Topside Controller <Full Duplex RS485> ROV Controller
NCUWI
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Joined: Nov 25th, 2011, 3:27 am

Re: New to Arduino, what should I get?

Post by NCUWI »

@Bindo - You make a valid point, I will keep that in mind.

As I read more about Arduino, it sounds like I'm better off using separate Arduinos for each task: one for servo control / RS-485 comms and another one for sensor data to video OSD. Does that sound right?
Bindo
Posts: 112
Joined: Apr 7th, 2015, 4:42 pm

Re: New to Arduino, what should I get?

Post by Bindo »

You only need an arduino for the rov, and topside. Arduino Mega is probably the best option.

If you look at KR2_diving's thread, there is a link to arduino "easy transfer". It works really well and I've looked at the raw data, it's pretty much the most efficient way to send data over serial.
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