ROV design

On Mon, 15 Oct 2007 10:39:10 -0700, "Wayne C. Gramlich"
No, you transmit video using two wires of the cat-5 (just like you would
through coax). The control information is transmitted using 3 other wires (ground, plus the two differential lines) over RS-485.
A friend of mine has a water-based ROV, and that's exactly what he does.
Later, Jon
-------------------------------------------------------------- Jon Hylands snipped-for-privacy@huv.com http://www.huv.com/jon
Project: Micro Raptor (Small Biped Velociraptor Robot) http://www.huv.com/blog
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jon Hylands wrote:

Jon:
Sorry, I selected the wrong message to reply to. I was answering the the question:
Also could I transmit the video over the RS-485?
To which, my reply is basically "no".
Once you have ethernet and cat5, there is no compelling reason to use RS-485 any more, just use ethernet in both directions.
-Wayne
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That does seem the route that would be the easiest to go. But is there a way to do Ethernet with out having a computer? I'm trying to make this as least expensive as possible. I am also trying to make the electronics kind of from scratch (PCBs, circuits). I don't want to have to buy a bunch of $50.00 components to make this work (Computer, Ethernet I/O board, Webcam, Etherent Hub).
I was hoping there was a way to take all my operator panel controls and serialize them some how to send to robot. I guess I could do it with an A/D that has a serial out and attach all my analog controls to it, I have one like this on my balancing robot. But then I would still have the one digital switch on the panel, I could run just a single wire along with the serial wire for this.
The biggest thing is that I did not want to have to pay the money for a 100' video cable. So, I wanted to be able to send this signal over the same comm channel as all the rest of outputs. But that doesn't seem to easy to do.
Thanks again for everyones ideas and help, it gives me lots to think about, Joe McKibben
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Joe McKibben wrote:

[snippage]
The basic ways of doing video that I know of are:
1) CCTV (close circuit TV) camaera; NTSC (or PAL) out; it can be hooked directly to a TV. Long cable is expensive. 2) WebCam => USB. A long USB cable is pricy. USB => Laptop 3) WebCam => USB => Ethernet. Ethernet cable is cheap. Ethernet => Laptop 4) CMUCam => serial port. Slow. Cable is cheap though.
Pick your poison. When you add in cable costs, it is going cost a small chunk of change.
I am currently exploring 3). I have found that there are inexpensive wireless routers that have a full version of Linux inside of them. For example, the LinkSys WRTSL54GS has a 256MHz MIPS architecture CPU in it, 32MB of flash, 8MB Ram, 5 Ethernet ports, 1 Wi-Fi Port, and a USB port. It can be run off of a 7.2V rechargeble battery that consumes 9 watts. These routers currently cost ~$100. The site:
<http://www.openwrt.org/
has the software to download into it. This is not for the faint of heart tho'. If you screw up, you "brick" the router converting in from a sophisticated piece of electronics into a brick suitable for holding down papers.

No, it is not easy to do.
-Wayne
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.