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Topic: Rov tips and solutions with long theeter (Read 391 times) previous topic - next topic

Nesredna

Nov 13, 2013, 10:23 pm Last Edit: Nov 13, 2013, 11:32 pm by Nesredna Reason: 1
Hi. I'm in the development of my own ROV, A kind of deepwater project, capable of diving to about 680 meter.
all the trouble I had with the control and communication I think some of you could be spared for therefore this post.

I'm using 1 arduino nano and 1 arduino uno and a Mega for the control and communication, and a digital compass breakout board for heading data.  A 24 bit adc spi breakout board for the pressure sensor to get a reasonable reading of the dept, A couple of Dallas temperature sensors, 2 for monitoring the electronics and the batteries and 1 for water temperature. 5 esc and 5 brusless motors for trust and vertical controll, some H-bridges to control the motors on the robotic arm to come.
I use 2 breakout boards for rs-485 serial communication between control unit and ROV running i half dublex with easytransfer library I'm now down to 4 wires in the cable, that is a common ground, 2 wires for tx an rx, last wire is analog videofeed from ROV
using the common ground too, works excellent.  in over 700 meters of 4 wire cable !!!

in the control unit i have 1 nano and 1 uno, the uno runs a video overlay shield so I get all vital info in the video display.
the nano collect analog and digital input from yokes an knobs and send the commands to the mega in the ROV.
The MEGA collect temp, dept, heading, and other vital info such as amp and voltage from the battery and send it in return as compliment for the controlling data and of course controlling all the motors ect.ect.

if some interest in the project I could put out some more info

Best regards

CrossRoads

Wow, that's pretty deep!

32-bit ADC - that's impressive too.  What chip are you using for that?
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Nesredna

#2
Nov 13, 2013, 11:29 pm Last Edit: Nov 13, 2013, 11:32 pm by Nesredna Reason: 1
Ups. sorry 24 bit mistype
breakout somewhat similar to this just with spi instead couldn't find the one I bought
http://www.ebay.com/itm/24bit-analog-to-digital-converter-ADC-module-serial-interface-AVR-STM32-arduino-/121022291106?pt=LH_DefaultDomain_0&hash=item1c2d7d9ca2

yeah deep down to above 68 bar of pressure or almost 1000psi

zoomkat

Quote
I use 2 breakout boards for rs-485 serial communication between control unit and ROV running i half dublex with easytransfer library I'm now down to 4 wires in the cable, that is a common ground, 2 wires for tx an rx, last wire is analog videofeed from ROV


You might be able to reduce the conductors down to two, the center conductor and the outer ground wire in a single coax cable. Might actually get down to a single wire, a long "antenna" between the ROV and the surface. 
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)

SVSeeker

Very interested in your project.  Just started work on an ROV with 2000 ft depth capability.   Have you tested your communication in seawater?  I'm wondering if it would degrade the signal.   I was looking at using ethernet over VDSL2 converters on a single pair.   I'd also be interested in your ideas for a depth sounder and umbilical cable selection.

Thanks
Doug
SVSeeker.com

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