Re: [PSUBS-MAILIST] Preasure Gauge

["Sean T. Stevenson" <cast55@telus.net>]

OK - now I understand.  My only experience with ROVs has been with larger vehicles.  I was a technician with the ROPOS team for a while, and I had a hand in building this one for JAMSTEC.  ROPOS in particular was interesting - it had mechanical gauges outside of the normal field of view of the camera, but the camera could pan side to side to see them, providing backup information in case telemetry was lost due to a fiber break.  If I recall correctly, the umbilical had nine optical fibers in it, and the telemetry could be configured to multiplex multiple signals on a single fiber in case of a loss of one or more fibers.

Anyway, as far as your application, that's a new one to me.  Difficult to speculate on what would be most appropriate for a vehicle (tool?) that size, but my gut instinct is to use some sort of strain gauge configuration.  You would need to choose a location for strain gauge mounting that exhibits both a linear stress relationship with depth, as well as sufficient sensitivity for the gauge to be accurate, but once the gauge is properly installed, it is sealed (get the ones with the integral plastic backing) - these things are pretty robust, apart from the wires which you can protect accordingly.  Strain gauges themselves weigh next to nothing, and the strain gauge amp is probably small enough to position in an unobtrusive location.

-Sean


George Slaterpryce wrote:

Application will be for ROV depth calculations.
Everything on the ROV runs through the various Mcs and then back up to the control station (laptop) so everything I do either has to have video surveilence so I can read the gauge (not really the best solution) or must electronicly report back to the MC so it can relay it back up to the laptop.

Weight is an issue. I'm trying to design a 1-liter displacement ROV (micro-rov, camera with thrusters) which means I have 1 kilo to play with while still trying to make the preasure hull withstand the preasure at 100m. So micro-electronics and the smallest things I can find to do a job are my biggest obstacles.

I've even considered using teflon for the hull material to save weight.

George Slaterpryce

************************************************************************ ************************************************************************ ************************************************************************ The personal submersibles mailing list complies with the US Federal CAN-SPAM Act of 2003. Your email address appears in our database because either you, or someone you know, requested you receive messages from our organization. If you want to be removed from this mailing list simply click on the link below or send a blank email message to: removeme-personal_submersibles@psubs.org Removal of your email address from this mailing list occurs by an automated process and should be complete within five minutes of our server receiving your request. PSUBS.ORG PO Box 311 Weare, NH 03281 603-529-1100 ************************************************************************ ************************************************************************ ************************************************************************