Controlling HVAC with Second Temp Sensor

[mstarks01]

I have an Elk M1G and an HAI RC80 thermostat. Both work fine.

At night, I would like to control the fans and HVAC based on the temp where we're sleeping, not where the thermostat is located.

I know there is a remote temp sensor for the RC80 but it looks to me that if I install that it would completely disable the local sensor.

I am aware of the Elk remote sensor and it seems to me that this could be an option if I read it every minute or so and start/stop the HVAC based on that reading (setting the temp of the thermostat arbitrarily high/low as needed, with a delay to prevent short cycling).

I have considered reading each room individually for fan control but that seems like it could get expensive, especially considering the Elk sensor.

1-wire seems to be an option, although I am not entirely clear on all of the components I would need to make this happen.

+1 points for WAF friendly sensors that disapear into the background.

Are there any other options I am not aware of? What would be the best option in this scenario? Thanks.

 

[Automation]

I use wireless Oregon temp and humidity sensors with the RFXCom "European" receiver (433.92MHz receiver for X10 and many other protocols. With interface.) with HomeSeer to control my HVAC fan. This receiver is one of my best "parts" of my automation system as it will receive all kinds of RF devices.

 

[Michael McSharry]

The HAI thermostat has an RS-232 interface and you can remotely control it via this mechanism. You would need another independent temperature sensor that the ELK could read and with rules command the HAI 80. I would think that you should also be able to run fan in a parallel configuration of the thermostat and a relay controlled bythe ELK, but I'm not certain of the implications to the thermostat if backdriven.

As mentioned in the prior post Homeseer provides some ease of interface as it has software that controls the thermostat and a variety of way to input remote temperature measurements.

As an interesting device the $35 WebControl provides and IP interface with relay outputs and temperature inputs and contains a simple Boolean logic engine that allows you to setup rules to control the relay based upon the temperature (or humidity).

 

[AceCannon]

This is a link for a Qkits module that will read four 1-wire temp sensors:
http://store.qkits.com/moreinfo.cfm/VK011

This is a link to a place in IVB's thread where he talks about implementing the device with his CQC deployment:
http://www.avsforum.com/avs-vb/showthread....or#post10512804

This is a link to the thread at Charmed Quark that talks about the CQC driver for the Qkits device and actually contains the driver itself:
http://www.charmedquark.com/vb_forum/showt...highlight=VK011

I am planning on doing this someday. So many other things on the list!

 

[mstarks01]

This is a link for a Qkits module that will read four 1-wire temp sensors:
http://store.qkits.com/moreinfo.cfm/VK011

That looks like a pretty affordable solution. Do you know if it will interface with the Elk M1G. Seems possible since it's serial but I don't know how the Elk would tell which sensors are for which rules..

 

[AceCannon]

That looks like a pretty affordable solution. Do you know if it will interface with the Elk M1G. Seems possible since it's serial but I don't know how the Elk would tell which sensors are for which rules..

No, it will not directly interface with the Elk.

In your spare time check out CQC. There is a driver for the Qkits, as noted in my above post.

 

[Michael McSharry]

You really do not need a big 24/7 PC-dependent piece of software such as Homeseer or CQC to do the simple control you are trying to do. Something as simple as two thermostats would be a clean way to achieve your objective. The downstairs one would be programmed to have very high setpoint at night and normal during the day. The opposite for the upstairs one. You just need to check if a direct parallel connection will work of if you need to add relay. Of course if you realy desire is go full blown HA then lots of choices are available.

 

[Lagerhead]

Have you considered an Elk keypad (M1KP with a built-in temperature sensor) in the bedroom area? It would probably work with the rules you suggested, and give you additional convenient on-the-spot control of your temperature and fan preferences, along with system arming etc.

 

[mstarks01]

Have you considered an Elk keypad (M1KP with a built-in temperature sensor) in the bedroom area? It would probably work with the rules you suggested, and give you additional convenient on-the-spot control of your temperature and fan preferences, along with system arming etc.

Hmm, not a bad idea. That's a bit more expensive than I need just for temp control but I have been considering adding an additional keypad to the master anyway. I need a way to have the wife disable the alarm without exiting the room when I am not there. Maybe I can find a used one here...

The more I think about it, the more I think I am ultimately going to need a PC-based solution for everything I want to do. I want the Elk to continue to control the stuff that requires high availability, but I would also like to capability to do temperature logging from multiple (maybe 8 or more) locations.