Use of Velleman k8023 as control system

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Kjetil
Posts: 65
Joined: Dec 11th, 2010, 4:18 pm
Location: Norway

Use of Velleman k8023 as control system

Post by Kjetil »

Planning to make a ROV with onboard battery and only one Cat 5 cable as teather.

Planning to use a total of 3 Velleman K8023 http://www.designnotes.com/Merchant2/me ... _Code=recu

With the Velleman K8023 I can control 10 relays with use of only 2 wires.
Planning to use a total of 3 sets.

Two for controling up to 20 relays
One the opusit way to get signals back to surface (compas and water detector)

They I will use a total of 6 wires. Then I only have 2 wires left for the camera. Planning to have several camera on the ROV and need at least two extra wires.

Anyone know if its possible to connect several Velleman K8023 to the same two wires? Or if there is any other metodes for controlling 20 relays with use of only two wires without use of a computer?

Sorry about all the spelling mistakes, writing this with my Iphone with no spelling check.
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Rover
Posts: 108
Joined: Jul 18th, 2011, 10:23 pm
Location: Minnesota

Re: Use of Velleman k8023 as control system

Post by Rover »

The K8023 uses a serial communication, looking at small voltage variations on the Tx and Rx lines. Each K8023 requires it's own signal wires.

Are you going to use the K8023 outputs to control an external relay board, or is the relay coil current draw less then the open current rating of the K8023. My last ROV used smal H-Relays directly controlled by the K8023. It worked great. One H-Relay per motor to control FWD and REV.

On that ROV, I controlled the left and right thrusters with 4 outputs, 1 for lights, 2 for camera tilt, two for focus, leaving one un-used.

The vertical thruster was controlled with a PWM.

So the tether had.... (one cat 5 and 2 power wires)
2 wires for Rx and Tx
2 wires for video
3 wires for the PWM potentiometer
1 wire used for leak detection
1 set of power wires

Good luck, let us know how your build goes.

Jim
Kjetil
Posts: 65
Joined: Dec 11th, 2010, 4:18 pm
Location: Norway

Re: Use of Velleman k8023 as control system

Post by Kjetil »

I`m going to use small relays like these http://www.taydaelectronics.com/servlet ... T-5/Detail I have testet them against the K8023.

Attached is shematic of the control system. And shematic of the ballast system and compass.

For the camera I`m planning to use a relay to switch between two or maybe three cameras, and transfer the video signal with the use of video balun like these http://www.ebay.com/itm/2-x-Coax-CAT5-C ... 2c53e0c49f Have never tried these before. Have only connected the videosignal directly to the cat 5 cable. I hope that this will give a better image. Planning to have one video balun for each camera and have the relay between the balunes and the cable to surface.

Have anyone tried to use a standard relay for swithing between cameras? will this give disturbance for the video signal?
ROV PT2 control 2.pdf
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ROV PT2 compass.pdf
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ROV PT 2 ballast system.pdf
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derelicte
Posts: 292
Joined: Aug 1st, 2011, 3:08 pm

Re: Use of Velleman k8023 as control system

Post by derelicte »

you should be able to switch video through a relay with no problem. the monitor will lose sync when the relays open and close, but it should sync up in a second.

we have done this in the past at work.
Kjetil
Posts: 65
Joined: Dec 11th, 2010, 4:18 pm
Location: Norway

Re: Use of Velleman k8023 as control system

Post by Kjetil »

Thanks, will this also work if I put the relay before the video Balun?
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bigbadbob
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Joined: Nov 28th, 2011, 10:24 am

Re: Use of Velleman k8023 as control system

Post by bigbadbob »

I like your relay wiring Kjetil. grounding the motor pins when they're not in use will provide an electric brake on them which will allow fast direction changes.

If you supply the rov from the surface then you only need one wire (vtx-) per velleman board as the +vtx/positive supply is common to all and can be used to supply other stuff too. this involves resistor and voltage regulator changes on the boards but is simple to do.
Kjetil
Posts: 65
Joined: Dec 11th, 2010, 4:18 pm
Location: Norway

Re: Use of Velleman k8023 as control system

Post by Kjetil »

I did ask the same question on the Velleman Forum, they told me that I had to use two wires on each board since there was communication on both lines. I do not think that I will use the Velleman board, I working on using two Arduino Mega card and RS-485 instead.
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bigbadbob
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Joined: Nov 28th, 2011, 10:24 am

Re: Use of Velleman k8023 as control system

Post by bigbadbob »

I just saw your post on the velleman forum, as standard, supplying the power from the reciever end, you need two wires for each, but with my modification i supply +12v, 0v and vtx- from the controller end and you could run 2 recievers using +12v, ov and two vtx- wires. (one for each board) this is still 4 wires but the 12v and 0v supply my camera etc as well as the reciever.
Let me know if you want more details on my mod or if you want to part with your velleman kit, i fried my reciever pic and need another. this was a wiring error on my part and not a problem with the mod.
Kjetil
Posts: 65
Joined: Dec 11th, 2010, 4:18 pm
Location: Norway

Re: Use of Velleman k8023 as control system

Post by Kjetil »

That wold be nice to get a shematic of your set up. I like to keep my four 8023. Just in case.
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bigbadbob
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Joined: Nov 28th, 2011, 10:24 am

Re: Use of Velleman k8023 as control system

Post by bigbadbob »

I've had another look at the schematics and this would work fine using onboard batteries.
VTX+ is just a 10v supply from the reciever to the controller so doesnt matter which one it comes from, as long as both recievers use the same 12v supply and gnd.

Image
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