-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 If you only want to check for a full or empty tank you could have a float that blocks the entry or exit port then just sense the overcurrent (or magnetic sensor for float) then just have a smaller trim tank that you set by hand. No worries then about measuring, in fact you could do the measuring by several small tanks and fill the bladders digitally, you would then have a T-T2 digital to flotation converter. hmm, sounds good to me, each T-T2 tank uses a bladder and has electronic valves to switch between filling with air or going to an air recovery pump, other side of bladder to ambient water. still need the trim tank (or ballast) to get neutral at a digital midpoint. Four tanks gives 7 rates of ascent or descent, could probably get away with less. Space looks tight, but would depend on the buoyancy you have in the rest of the sub as to the practicality of subdividing you current tank cya, Andrew... - -----Original Message----- From: Andy Shaw [SMTP:andys@SCO.COM] Sent: Thursday, October 19, 2000 11:03 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Help water level Actually the issue is not the depth of the sub (I already have depth sensors using pressure on the sub), this issue is providing closed loop control over the amount of water in the ballast tank. I'm rapidly coming to the conclusion that this is heading towards one of those "If I wanted to get to X I wouldn't start from here!" sort of conversations. I think that using a different type of ballast tank (probably a piston style one as described by Andy Kunz in an earlier mail and as often used by some of the sub builders in Germany) would be a better way to do this. Shame I've already built the thing (and to be honest it works really well - but I do like to try new things!). Anyway if anyone is interested the current configuration can be seen at http://freespace.virgin.net/andy.shaw/subcomsep2000.htm The bottom four pictures on the page show my sub. Click on the images to get a bigger version. You can see the dive module with ballast system etc. If you look closely you should be able to see the 16C71 which currently controls the thing. More details are at: http://freespace.virgin.net/andy.shaw/microcon.htm Andy - ----- Original Message ----- From: "Stouchton" To: Sent: Thursday, October 19, 2000 3:49 PM Subject: Re: [EE]: Help water level > How about this: Looks like what is of concern is not the sub's depth > from the bottom, but its depth from the surface. What about using an > upward firing depth sensor... look for the water air discontinuity. -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.8 for non-commercial use iQA/AwUBOe9IfEAhpS53eUNhEQIZdwCfV+EvF1WwnrWZef+a5s7FY4jxoU8AoNs0 ekcxBZA805zuCmZORMLNTthG =9zum -----END PGP SIGNATURE----- --------------------------------------------------------------------------------- The information transmitted is intended for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination, copying or other use of, or taking any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you have received this in error, please contact the sender and delete the material from your system. Utility Services Corporation (USC) is not responsible for any changes made to the material other than those made by USC or for the effect of the changes on the meaning of the material. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads