The tube can be open ended, no need to seal it. I thought it might not work, but can't think of a reason. The capacitance would read the same. For the tank, I put the tube on the outside because it was easier, and well, it never really occured to me to put it inside. Hmmm, motorcycle fuel gauge... I was originally going to put a small magnet on a float inside the tube, and have a few reed switches outside. That would work for a pond level indicator (reed switches are easier to deal with than hall effects), but you need to figure out how to stop the magnet spinning. Tony -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Alan B. Pearce Sent: Wednesday, 12 April 2006 9:04 PM To: Microcontroller discussion list - Public. Subject: Re: [OT]: Fountain Project- Help Me Pick A Sensor? >I found the article on the Parallex website: > > >I still think it's a neat solution, cheap too. I was envisaging a tube that went down into the water. have to think how I can apply this to a water butt. >If you put a PIC on top, you might as well send back >the exact water level! True, but also measure the temperature and turn on some mild warmth if it looks like freezing, so the water butt doesn't get damaged, in my case. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist