On 04/13/2012 12:41 PM, Ben Okopnik wrote: > On Fri, Apr 13, 2012 at 10:10:51AM -0400, SteveW wrote: >> That's waaaaaay to much to think about, Ben<g>! >> >> Besides, given the size of our boats compared to Norm's, I'm sure you >> couldn't fit a milk jug float into your bilge as I certainly couldn't! > Sorry, I should have been clearer. What I meant was the general > principle of removing the switch from the wet, possibly oily, etc. muck > in the bilge, which solves a large number of reliability problems *and* > lets you use better quality, industrial-duty switches (instead of > whatever the float switch manufacturer sticks you with.) Shallow bilge? > No problem: use a long lever - say, a piece of SS TIG welding rod - and > solder a carburetor float (or even glue a ping-pong ball) to it. Twist a > single loop into the other end of the wire, about an inch from the end, > and put a screw through it and into one of your frames right above the > bilge. Float rises, back end of your "see-saw" comes down... fairly > obvious how to proceed from there, right? > > Bonus: if you use the after-run circuit as I'd suggested, you already > have a high-gain "switch" in place - the MOSFET. This means that you can > use a low-power switch on the above float - a standard magnetic door > sensor, with a sealed reed switch. No moving parts to wear out. All > that's left is using a good-quality pump - say, a Johnson, with one of > those nifty "run-dry" neoprene impellers. > > There ya go, a free engineering session for your dream bilge pump. :) > > > Ben This seems like dejavu but I recall seeing a pump demonstrated at a SSCA meeting that had a controller built in. The pump would run at a specific interval, like every 5 minutes or so and the controller would measure the current draw. If there was no load on the pump, it would turn off. If there was a load it would monitor the current and shut off when the current dropped off after a slight delay. I'm thinking of using an Arduino to build same thing. Of course I'd still have a conventional pump for backup. Sounds like a fun project. I even went so far as to pick up some 0.1 ohm resistors. The Atmega328 has a reasonable ADC on board.
Now if I can just find that round tuit. Jim. _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
