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NOTE: To get off this list, send email to majordomo@aqua.ccwr.ac.za with the body of the message containing the line: unsubscribe sowacs Hi Pete, Thanks for the encouragement. It wasn't that long ago people had to strap a CR10 to a rain gauge merely to count the tips. I was just checking to see if there might be some interest. Your right, better, cheaper dataloggers are always around the corner. I build dataloggers purely for the enjoyment, and I would assume most professionals engineers in this field do so as well. With the cost of integrated circuits dropping every day, I doubt anyone is getting rich. I'm not familiar with the watermarks, I use TDR almost exclusively. Richard Allen has a very nice web page detailing interfacing watermarks to Onset's dataloggers. http://www.kimberly.uidaho.edu/water/swm/ I have heard of individuals getting good results with watermarks and gypsum blocks hooked up as the resistance source in an RC astable multivibrator using a 555 timer. As the resistance of the block changes, the frequency output of the timer does as well. This way your running a switched DC through the sensor. If you would rather have a voltage output, drop the timers supply current across a low value resistor. The 555 timer is very stable, and with a good quality capacitor in the RC network, should produce good results. Regards, Steve Sargent http://www.slsargent.com/ At 07:36 PM 04/01/2001 GMT, you wrote: >NOTE: To get off this list, send email to majordomo@aqua.ccwr.ac.za >with the body of the message containing the line: >unsubscribe sowacs > >Everyone wants to build a better or cheaper logger. A plc can handle >that already and it can do the switching for multiple sensors. What it >cannot do is create the signal for a Watermark that I can use for input >to an analog card. Does anyone have a simple signal generator or >schematic that I could use? Thanks Pete Pankey > > > >