[colug-432] Monitoring water level

[jep200404 at columbus.rr.com]

On Sat, 26 Jan 2013 18:50:14 -0500, jep200404 at columbus.rr.com wrote:

> To go from water height to PC, I would probably use the line-in 
> audio jack. The [] _frequency_ of the audio signal would 
> indicate the water height. 

The more I think about this, the more I like it. 
No special hardware or drivers would be required on the computer, 
so one could use almost any computer that can run Linux. 

Debugging the hardware would be easy. Just connect the signal 
to amplified speakers and move the water level. You could 
_hear_ it working. One could record the signal with a tape 
recorder or MP3 recorder at 8kbps. One could plug the signal 
into a phone line interface/switch. When you call a particular 
extension at home, you would get an ear full of water height 
tone. 

Also, the sensor would not need complicated electronics, 
just classic analog stuff, although it would probably be easier 
to make with op-amps than without.