The arrangement with which I presently control the swamp-cooler is the one that came with it. It has a sort of thermostat, which, is just about twice-worse-than-useless, together with a selector switch, which provides "pump-only", "High-Cool", "Low-Cool", "High-"Vent", and "low-vent", along with "OFF". What I find I need is an additional control to switch on/off the water supply, as I've found that the float-valve often fails to shut off the water supply, thereby wasting several hundred-dollars' worth of water per month. This is difficult to remedy, presently, in part because it takes a while to operate, and because it's hard to monitor. I guess that a "pump-on"a signal should suffice to control an inline solenoid-operated valve to control the water supply. This is available in the form of the return from the pump motor AC supply line would suffice.

The reason I'm inclined to use the LCD is that (A) I know how to do that, not that I can't use LED's, and (B) I already have both the hardware and the code.

The reason I'm willing to buy is that it's a "pain in the *ss" to work the packaging problems, particularly since I no longer have a full machine shop, which I once did, and it's a big enough pain just to make and house the boards exactly suited for the LED's or LCD's that I need, and because I don't expect to co-locate the thermostat/control logic with the AC lines, which provide the power. Since I want to use the power line to the pump motor, 120VAC, to power the solenoid valve (in parallel) controlling the water supply. With the arrangement I'm envisioning, I'm thinking a serial keypad would be adequate as input, and, a serially interfaced LCD would be adequate as output.

I'm not "hard-over" on any of that, however.

RE