Furnace run timer

GICU812

I need to monitor the time my furnace is running, the thermostat outputs 24AC, will this setup work? Can anyone reccomend something better with common componets?



Code:

main:

do while (in0 = 1)
loop

do while (in0 = 0)
counter = counter+1
pause 1000
debug "Running Time", counter, "Seconds", cr
loop

goto main

I guess I'll need a pullup on the pin too

Mike Green

There are all kinds of possible alternatives, but what you've shown is simple and likely to work (with the pullup). For other suggestions, have a look at the Industrial Control and Process Control tutorials that Parallax has available for download.

Chris Savage

Another solution with a lesser part count is to use an opto designed for AC. The output can go directly into the BASIC Stamp I/O pin (with pull-up) and would be isolated. 2 components including the resistor. Take care.

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Chris Savage
Parallax Tech Support

GICU812

Thanks guys. In hindsight, that was a rather lame question, I guess I worked out most of the details as I was making the post, lol. Well thanks for listening to me anyway.

Though im sure there is more efficient code for this. Im going to be doing something like this in another, larger project, so any suggestions on code would be appreciated.

Chris, thanks for the suggestion, for now I want to build this when I get home tonight. Radioshack barely sells resistors anymore, and the electronic places close at 5, so im limited to hardware I have on hand. I may use that idea if I go anywhere with this circuit, for now its just to see why my electric bill was $149 last month, Im thinking the 20kw electric furnace might have something to do with that. It wasnt even that cold...

Post Edited (GICU812) : 11/15/2007 4:31:08 PM GMT

sdy

Man, I wish my bill was that low. My hot water heater eats electricity, then the clothes dryer, the stove, oven, 21 cubic foot freezer... And then there's the oil bill for heat!

Chris Savage

No problem…I used to live in NY and had a forced air furnace. At once time I posted the code and schematics for a Digital Thermostat I built to take the place of the Honeywell dial thermostat. Not only could I schedule multiple programs per day, but I could log activity if I wanted to. Sometimes the smaller projects lead to bigger ones. Take care.

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Chris Savage
Parallax Tech Support

steve_b

Hey Chris, do you still have that information? Was that the yahoo group days?

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<FONT>Steve



What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
Lee Travino after the second time being hit by lightning!

Chris Savage

Steve,

Actually it was from the Yahoo Group days, but I later had some issues with the temperature reading from the DS1620 which Tracy Allen helped me with and I reposted the project on the forums a few times. I could find one of the posts…Let me see…

Ah, here we go, I found the code for now…The LCD was using a PIC-an-LCD interface and the relay is self explanatory. Other connections are documented in the code.

http://forums.parallax.com/showthread.php?p=519605


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Chris Savage
Parallax Tech Support


Post Edited (Chris Savage (Parallax)) : 11/16/2007 8:59:36 PM GMT

GICU812

This is the immediate interest, but im working on a HVAC control system. I've got plans for a touch screen interface with zone heating \ cooling. I hope to be able to close the dampers with the stamp to direct airflow where I want it, and shut off rooms im not using. Before I go that far though, I need to finish my car project.