newbie question

smk8er

Hello all and thanks for looking at this. I am very new to basic stamp and i have a Boe Bot on its way to me as i am typing this. Eventually i will be building an underwater ROV and would like to be able to operate it thru my laptop with a tether. Can i do the following with basic stamp: run a video feed with a compass heading and also control motor functions with basic stamp or is this to much? I know i have a long ways before this happens. But i would like to know so i can continue looking around. I also cant wait to build the boe bot and get it running. thanks again all!

Bruce Bates

smk8er -

Based on just what you've said so far, I don't see anything particularly challanging, with the following caveats. There may be others as well, as you get into the design phase.

The video feed should be completely external to the Stamp, serviced by a piece of coax embedded in the tether, except if you choose to use an OSD (on screen display) technique to insert the heading text and overlay the compass heading on the video feed. If that appeals to you, take a look at the BOB-xx series of OSD modules here:
http://www.decadenet.com/

The motor control issue is fairly trivial, as is/are sending any additional control signals. The signal path within the tether should have to do/be one of the following, in order to minimize the number of tether conductors. Here the concerns are weight, cost, size (diameter) and associated water resistance (drag) of the tether:

a) Multiplexed using some method (time division or otherwise) such that signals from multiple sources can be sent on the same set of conductors (signal path) successfully,

or

b) An addressable, differential serial protocol, such as RS-485, might be used to allow addressing multiple devices on an individual basis, on the same "signal bus", with a fair degree of reliability,

or

c) Some polled method of retrieving the necessary signals and/or other information that must be sent to the surface via one signal path in the tether. This might be seen as a "commutator" technique; ergo the first "ping" to the ROV in a series, causes the first device to report, the second "ping" causes the second device to report, ad infinitum

or

d) Some yet unmentioned method (4-20 mA?) of utilizing the output of multiple devices on
one signal path, which signals can be successfully and accurately be separated at the surface for analysis and processing.

Lastly, I might consider one additional pair of wires which serve only an emergency purpose. If a signal comes across that pair to the ROV, it has only one responsibility - RISE!
That way, regardless of whatever else might occur, retrieval is made much easier.

Regards,

Bruce Bates

Orion

There are a few others down your same path, someone posted not too long ago about using fiber optic cable to do the same thing. The customer apps portion of the parallax site also has someone doing a rov if my memory is correct.

smk8er

Thanks for the reply guys!

smk8er

Bruce, Yes i want on screen display of navigation and depth. Thanks for that link that XBOB is what i am eventually going to look for. You gave me some ideas i need to think about and work on. Again thanks all for your input!