Scrubber usage indicator

bathtub

I have seen at least one scrubber usage indicator advertised out there- now besides the obvious simple timer mechanism, has anyone got any reasonable scrubber usage systems set up? was thinking hot front propogation through linear scrubbers, or indicative thermocouples in radials....
thoughts/ suggestions
????

Genesis

I'm considering making a "temp stick" type of indicator for the K1. Its a bit tricky due to the scrubber design, but I'm sure I can make it work - the question becomes how many sense points do I need to make it practical, and how do I fit that in the scrubber and then talk to it in a way that's reliable.

I'm considering some kind of multiplexed system - the idea of running a separate ADC channel for each sensor is the simple way, but it would require a lot of ADC channels! The LM34DZ is a reasonably small (TO-92 transistor-size) package with a nice span suitable for direct ADC input and good resolution and accuracy (typically 1/2 degree F) which might work, but the interconnect to it might get a bit messy. I use the LM34s in a lot of industrial and home control applications - there are three of them, for example, in my pool plumbing (encapsulated in epoxy) that are used to control the solar and gas heating systems for my pool and hottub, and another couple are inside the house as the "building block" basis for digital control of my home's HVAC system.

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket