Any ideas how to design a rate of change trigger system?

[TimB]

Hi All

I'm looking to improve a threshold trigger system. Currently I have a software based water level control system. It works out if water is seen by looking at an ADC reading and looking for a level jump from what it considers a known state. The known state changes as the conductivity level changes. So it is able to continue working as the conductivity level changes

Now I'm looking to perhaps make it in hardware

My question is would it be better in hardware or should I keep with software. If hardware any pointers how to do it?

Thanks
Tim

[JonW]

It sounds like you have implemented a software data slicer (comparator with a conductivity-based threshold as the reference that changes at a lower or averaged rate with respect to the water level).  Take a look at this Analog Devices APPNOTE on data slicers.  Don't be put off by the RF implementation; it's just the theory of data slicing that you may be interested in.

[TimB]

Thanks Jon

Perfect info

Tim