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Richard Erlacher
08/07/12 16:52
Read: 463 times
Denver, Co

#188012 - Valid points ...
Responding to: Per Westermark's previous message
Per Westermark said:
It can be a quite fun project to build one.

If you buy a system, they are normally quite expensive and you still have to either pay money or spend lots of own time to try to set it up so it does what it should.

With a home-made solution, it's also easy to have a log function so a PC could retrieve historic information for all sensors and output states. A home-made solution also allows you to feed faked sensor data to test the system - a live system normally requires you to tweek the parameters and then wait a week and see what happened.

I would probably skip the LCD and settle for a couple of LED - and instead have a USB-to-serial cable connected, allowing a PC to show detailed information why the LED:s just show simple things like "operating", "fan on", "pump on".

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.


List of 10 messages in thread
Is there a such a product ?      Richard Erlacher      08/07/12 11:31      
   Build it      Per Westermark      08/07/12 12:19      
      Valid points ...       Richard Erlacher      08/07/12 16:52      
   Typical Controls      Michael Karas      08/07/12 15:54      
      One glaring weakness of most thermostats      Richard Erlacher      08/07/12 17:05      
         Development board      Per Westermark      08/07/12 17:20      
            Dev boards are my stock-in-trade      Richard Erlacher      08/08/12 09:51      
   Not Quite....      Michael Karas      08/07/12 16:10      
      Worth Investigating      Michael Karas      08/09/12 05:40      
         thanks for the link      Richard Erlacher      08/09/12 14:44      

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