I found the article on the Parallex website: I still think it's a neat solution, cheap too. I did something similar a few years back, measuring the water in a tank. I connected a tube to where a tap went at the bottom, and joined it the the 'capacitor guage' stuck on the outside. A PIC drove a 7 seg led, showing 0 (empty) to 9 (full). I can't remember exactly how I measured the capacitance though... like PC joysticks, I guess. Charge then bleed through a resistor, time how long it takes. It was close to the house so running power to it wasn't a problem. It occurs to me now that if I'd used clear tubing, you could see the water level too. Drop in a bright red bead to act as a float, like a kettle, but where's the fun in that. It also occured to me that it may not work if you stuck it in the middle of a pond, as opposed to the side of a tank, but I can't see why not. The capacitance depends on the amount air between the plates, having water on both sides won't make a difference. If you put a PIC on top, you might as well send back the exact water level! Tony -----Original Message----- From: piclist-bounces@MIT.EDU [mailto:piclist-bounces@MIT.EDU] On Behalf Of Bob Axtell Sent: Tuesday, 11 April 2006 11:25 PM To: pic microcontroller discussion list Subject: Re: [OT]: Fountain Project- Help Me Pick A Sensor? But, ya know, if I mounted a PIC10 right at the top of the probe itself, I could simply send a 5V "level" signal, can easily go 25', and no cable capacitance issues. My wife has some leftover 2-part clear epoxy that seals HARD. No moisture problems with that. I'm intrigued. Gonna look at Parallex site. --Bob >> Make a capacitor. Take a plastic tube, and run 2 strips of adhesive >> foil >> down opposite sides. You could use that stuff you put on windows for >> alarms, or copper foil that stained glass people use. >> >> I used the copper foil (because I had some), added wires to one end, >> then >> water-proofed it by putting some heatshrink over it (but I put some >> sealant on the ends first). >> >> The capacitance changes as the water level goes up & down. Works >> well. Won't corrode like bare wires either. Use clear tubing & >> heatshrink and >> it might not stand out all that much either. >> >> Of course, you'll need a PIC to measure the capacitance... and fire the >> solenoid... >> >> I got this from the Parallex website (Basic Stamp), there's an article >> about it on there somewhere. >> >> Tony >> >> >> > would it operate 25' from the fountain? I was trying to avoid having > the electronics close > to the fountain, or splitting it up...my planned electronics box is > near the water spigot & > outside electrical outlet... > > I already have copper shielding foil and a support to hold it...Do you > think I could use that > low-loss TV interconnect cable for a 25' run? That could be buried > alongside the power > cable to the pump motor. > > Good tip, thanks. > -- Note: To protect our network, attachments must be sent to attach@engineer.cotse.net . 1-520-850-1673 USA/Canada http://beam.to/azengineer -- 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