Maintain Water Level Between Two Preset Limits

[night_mare]

Hi I found a very nice circuit to maintain water lavel between two preset limits.
I made it and it works cool.
Its require a few component so very chip and all parts are available
Have fun   
Here is the link

http://electronicdesign.com/Articles/Index.cfm?ArticleID=9137

Please read the page very carefully including "Reader Comment" .

There u get some modification for the schematic.

Here u get the pages and right schematic

http://rapidshare.com/files/119097670/water_level.rar.html