Simple question for a simple task

[smasraum]

I've been interested in HA for a long time, but there are always more important things to spend money on, right?

Most of the posts here are over my head and much farther than I'd ever get in this house, but I think you guys could help/answer a question for me pretty easily.

I've got an old 2 story house (1967). In the spring and fall when the temps are nice, during the day, the downstairs will stay a great temp. Since that's where the thermostat is the HVAC system stays off. The problem is that over the course of the day the upstairs heats up until it's uncomfortable. The answer is to turn the fan to on to keep the cool and warm air circulating. The next problem is that I would prefer to not have that fan running for days or weeks.

I've got a plane Jane AC unit with a 7 day programmable thermostat. The AC is nothing special, not a split system or multizone or anything like that.

I'm reading about the 1-Wire stuff now and will be installing some weather sensors including at least 2 temp sensors inside the house. I was thinking that it should be fairly easy to set up a 1 wire system with a temp sensor upstairs and downstairs. If the upstairs temp hits a certain threshold or the temp differential between up and downstairs hits a certain threshold then the system could use a relay or switch to turn the fan for the HVAC system on. I assume that I'd need a diode or something to allow the thermostat to still function normally. I assume that I wouldn't want both the 1-wire system and the thermostat to both be on and the power to flow where ever. That's where a diode or two would come into play.

So, how easy do you guys think it would be to set something like that up? What are the pitfalls (other than frying my AC and burning down the house B))? What do you think I'd need/How would you set it up?

Thanks in advance

 

[smasraum]

I don't see us living here too many more years. I'll definitely be hanging around so I can add some serious automation to the next house.

 

[AceCannon]

Off the top of my head. .

1. you could use an Elk and an Elk temp sensor. When temp criteria are met, you could have rules for the Elk to tell a communicating thermostat (like the Aprilaire 8870) to switch the fan from AUTO to ON (and back). The compressor would still be following the thermostat's settings.

2. CQC could perform a similar function, but might be easier to configure with a 1-wire network.

BTW, what hardware are you using for 1-wire?

Some of these solutions might be over-the-top for this project, but you said you might be into this sort of hardware for the next house anyway. Get a head start.

 

[smasraum]

BTW, what hardware are you using for 1-wire?

Some of these solutions might be over-the-top for this project, but you said you might be into this sort of hardware for the next house anyway. Get a head start.

Nothing yet. I'm still reading "Weather Toys" (written to teach how to build a weather station using 1-wire gear including some java programming for 1-wire). I'll be using my old PC and several sensors/modules for temp, air pressure and humidity indoors and temp, humidity, etc... outdoors. I've seen that hobby-boards, aagelectronica, and datanab has several sensors available. It's my understanding that with the 1-wire system, you've got a lot of options, especially if you've got a good understanding of electronics and a good problem solving imagination.

Thanks for the reply.

 

[project_x]

BTW, what hardware are. you using for 1-wire?

Some of these solutions might be over-the-top for this project, but you said you might be into this sort of hardware for the next house anyway. Get a head start.

Nothing yet. I'm still reading "Weather Toys" (written to teach how to build a weather station using 1-wire gear including some java programming for 1-wire). I'll be using my old PC and several sensors/modules for temp, air pressure and humidity indoors and temp, humidity, etc... outdoors. I've seen that hobby-boards, aagelectronica, and datanab has several sensors available. It's my understanding that with the 1-wire system, you've got a lot of options, especially if you've got a good understanding of electronics and a good problem solving imagination.

Thanks for the reply.

I would use logtemp, in it you can set alarms for temp sensors, and IIRC switch a 1-wire switch on alarm. You could switch the green fan wire on when the temp hits xx, and off when it gets below.

Best of all, logtemp is free.

 

[smasraum]

I would use logtemp, in it you can set alarms for temp sensors, and IIRC switch a 1-wire switch on alarm. You could switch the green fan wire on when the temp hits xx, and off when it gets below.

Best of all, logtemp is free.

Cool, that sounds quick and easy. Thanks!

 

[icellama21]

AnthonyZ just posted a [topic="13181"]link[/topic] to a cool 1-wire logging/control device. The system featured also offers some details on how to build a system yourself. If you are thinking of expanding into home automation in the future you can look into getting an HAI or ELK controller, but it sounds like it may be overkill.

An ELK will work but the temperature sensors from a price/accuracy/performance/aesthetic perspective are probably the Achilles heel of the system, just about everything else you find will be better.

There are also a number of 1-wire interfaces to a PC is you want to have a dedicated PC running all the time. But for reliability you are prob better off with a controller.

 

[smasraum]

AnthonyZ just posted a [topic="13181"]link[/topic] to a cool 1-wire logging/control device. The system featured also offers some details on how to build a system yourself.

There are also a number of 1-wire interfaces to a PC is you want to have a dedicated PC running all the time. But for reliability you are prob better off with a controller.

Thanks, that link is interesting.

I've always got at least 1 PC running full time already, so that's not an issue. I'll probably be running the thing as a weather station for a bit before I'd try to interface with my HVAC system.

A big concern is having wires running from a sensor on the roof, to a PC and the HVAC system. A lightning strike could potentially kill HVAC and a PC. Ouch!

 

[Rupp]

AnthonyZ just posted a [topic="13181"]link[/topic] to a cool 1-wire logging/control device. The system featured also offers some details on how to build a system yourself.

There are also a number of 1-wire interfaces to a PC is you want to have a dedicated PC running all the time. But for reliability you are prob better off with a controller.

Thanks, that link is interesting.

I've always got at least 1 PC running full time already, so that's not an issue. I'll probably be running the thing as a weather station for a bit before I'd try to interface with my HVAC system.

A big concern is having wires running from a sensor on the roof, to a PC and the HVAC system. A lightning strike could potentially kill HVAC and a PC. Ouch!

I ran the free one-wire plugin with HomeSeer for a few years for all my one-wire temp sensors and one-wire weather station but I got tired of replacing all the sensors as well as the one-wire computer interface every couple of months because of lightning strikes. The irony is once I added a one-wire lightning detector lightning took out my entire network and the PC's com port. I move over to a Davis wireless Vantage Pro weather station and kept my indoor one-wire sensors. HomeSeer can use these temperatures as input to any event. For example I adjust my ceiling fan speeds based on the room temperatures, I use one-wire humidity sensor in all bathrooms to automatically start and stop my bathroom fans, I use one the temps to control my attic fans as well as notify me if the temps in the garage or under my house are near freezing so I can redistribute some heat. These are just a few examples of how you can integrate one-wire devices into your home automation.

 

[smasraum]

I ran the free one-wire plugin with HomeSeer for a few years for all my one-wire temp sensors and one-wire weather station but I got tired of replacing all the sensors as well as the one-wire computer interface every couple of months because of lightning strikes. The irony is once I added a one-wire lightning detector lightning took out my entire network and the PC's com port. I move over to a Davis wireless Vantage Pro weather station and kept my indoor one-wire sensors. HomeSeer can use these temperatures as input to any event. For example I adjust my ceiling fan speeds based on the room temperatures, I use one-wire humidity sensor in all bathrooms to automatically start and stop my bathroom fans, I use one the temps to control my attic fans as well as notify me if the temps in the garage or under my house are near freezing so I can redistribute some heat. These are just a few examples of how you can integrate one-wire devices into your home automation.

Exactly, that's my worry. I've read about surge suppressors that you can put inline that are supposed to save the adapter, but I'm dubious about anything stopping lightning.