Event Help to monitor a device

[nofreeze]

I am trying to keep a room cool in my house. I have a temp monitor in the room and have a zwave thermostat. I have setup an event that says

IF Room temp is above 78 degrees and the Harmony Hub is on then adjust the thermostat to 76 degrees. I want to then have the ROOM temp monitor continually check the temperature until it reaches 77 degrees then adjust the thermostat back to 78 degrees.

I idea is to turn our house AC on to cool this one room of the house but only do it when we are watching TV (Harmony hub) in that room and only when the temperature in that room is above 78 degrees. The biggest question is how do I have it monitor the temp and re adjust so it does not always do this when we have left the room or stopped watching TV.

Any help is greatly appreciated.

[tenholde]

Run an event every xx minutes that runs a script that checks these conditions and takes the necessary actions.

tenholde

[Uncle Michael]

I idea is to turn our house AC on to cool this one room of the house but only do it when we are watching TV (Harmony hub) in that room and only when the temperature in that room is above 78 degrees. The biggest question is how do I have it monitor the temp and re adjust so it does not always do this when we have left the room or stopped watching TV.

If the Harmony hub condition defines whether you are watching TV, and if you put it as a condition for the event to run, the event will run only if you are watching TV. Are you concerned about a situation where the TV is on, but there is no one in the room?

[Kerat]

Event Help to monitor a device

So, what your are talking about is called occupancy detection. I agree with @Uncle Michael, I think that detecting your harmony hub may not be enough. For my implementations at home I use a few variables to determine occupancy. I use a mix of Zwave Motion detection, BLLAN, and kodi monitoring. Eventually I will add in more aeotech Zwave surge strips (for power monitoring and control), and an alarm system.

To do what you are asking, you would need a virtual device assigned to determine occupancy in the HT room. Use detection of your harmony hub, as the trigger. setup an event to turn the virtual occupancy device to "on" when the harmony hub is detected as on. Then when harmony is detected as off set the virtual device to "off".

setup a separate set of events for your cooling/heating system that set run the cooling system when the temp is 78 or greater (this is trigger). Use the virtual device has a state of "on" as your condition. Set your next event for when your virtual device is changed to off (trigger). Turn off the cooling system.

setup a third event when the Temp monitor shows 77 degrees. Set up a condition where the virtual condition is on is a condition. Have it turn off the cooling system.



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[randy]

I am trying to keep a room cool in my house. I have a temp monitor in the room and have a zwave thermostat. I have setup an event that says

IF Room temp is above 78 degrees and the Harmony Hub is on then adjust the thermostat to 76 degrees. I want to then have the ROOM temp monitor continually check the temperature until it reaches 77 degrees then adjust the thermostat back to 78 degrees.

I idea is to turn our house AC on to cool this one room of the house but only do it when we are watching TV (Harmony hub) in that room and only when the temperature in that room is above 78 degrees. The biggest question is how do I have it monitor the temp and re adjust so it does not always do this when we have left the room or stopped watching TV.

Any help is greatly appreciated.

Reading this post I have as many questions as answers. The first question is why do you want the overshoot for the room temperature - setting the temperature to 76, then setting it to 78 when it reaches 77?

You don't indicate that you have any sort of room occupation device like a motion sensor so I don't understand how you can detect "when we have left the room". If we knew if you had such a device, then the events could be modified.

I would just utilize the thermostats own capabilities with these two events



In the on event the AC is turned on and set to 78. The room will cool to 78 degrees and keep it within the normal range of the thermostat. Mine are +-
1 degree. In the events you could set the mode or the set point, I have set both. By habit, I tend to set things based upon the assumption that either could be set incorrectly when the event runs. In the Off event the thermostat is set for future manual operation by setting the set point high as well as setting the mode to Off.

An air conditioning system cools at the same rate, no matter where the thermostat is set, so I don't understand what the overshoot does. If you want the overshoot, modify the TV On event to set the thermostat to 76 and add a third event to set the thermostat to 78 when the room is 77 degrees.



If you have a PIR or some other occupancy detecting device, it could be incorporated as well. For example you could use this event



If these don't hit the mark, then let us know what sort of devices you have and we might be able to cobble together some effective events.

[logbuilder]

I have mentally toyed with the idea of building a wifi arduino based thermostat. In my situation, I would be only controlling a furnace but that is not important.

The notion of 'overshooting' has come to mind. The concern is to prevent short cycling of the furnace. I think that applies to AC units too.

Lets say the target temp is 72 degrees. Do you turn the furnace on when it hits 71 and off when it hits 72? That seems logical but..... under the covers, does that mean you turn the furnace on when temp is 71.9 degrees and off at 72.0 degrees which gives you a .1 degree swing? That would create severe short cycling. It might make more sense that when the temp hits 70.9, turn the furnace on and then off at 73.9 which would give you a 3 degree swing and no short cycling.

Anyway, those are my thoughts on why 'overshooting' makes some sense. I haven't built the Arduino thermostat yet but the temptation of spending $15 on parts to build a functional equivalent of a $100 z-wave thermostat is compelling. My current thermostat is an offline device which is not seen by HS3 at all and thus no control. I want control.

[randy]

I have mentally toyed with the idea of building a wifi arduino based thermostat. In my situation, I would be only controlling a furnace but that is not important.

The notion of 'overshooting' has come to mind. The concern is to prevent short cycling of the furnace. I think that applies to AC units too.

Lets say the target temp is 72 degrees. Do you turn the furnace on when it hits 71 and off when it hits 72? That seems logical but..... under the covers, does that mean you turn the furnace on when temp is 71.9 degrees and off at 72.0 degrees which gives you a .1 degree swing? That would create severe short cycling. It might make more sense that when the temp hits 70.9, turn the furnace on and then off at 73.9 which would give you a 3 degree swing and no short cycling.

Anyway, those are my thoughts on why 'overshooting' makes some sense. I haven't built the Arduino thermostat yet but the temptation of spending $15 on parts to build a functional equivalent of a $100 z-wave thermostat is compelling. My current thermostat is an offline device which is not seen by HS3 at all and thus no control. I want control.

On heating systems they used to employ heat anticipators that would do the opposite and shut off the furnace burner, while the blower continued extracting the residual heat. Electric baseboard heaters also employed the same technique.

My heating system is hydronic. When a thermostat is set at 70, they will demand heat at 69 degrees and shut it off at 70. They are a 1 degree swing. There is no need for a heat anticipator, since the water is a maximum of 185 degrees, there is not much residual energy to be recovered by the little bit of hot water in an 8-16 foot piece of 3/4" copper. We just shut the zone valve off when the room hits target. I did design a bit of logic to prevent short cycles. I look at the temperature of the boiler and determine whether the burner needs to be turned on at the same time as the circulator. If a single zone is requesting heat, I will delay the burner until the supply temperature is below 150 degrees or a second zone creates demand. Since we have 6 active zones for heat, 2 passive zones (bathrooms that are not constantly heated) and a DHW zone, I seldom have short cycles of the burner. I log the circulator times so I can see how it cycles. You will notice that the only short cycles are "Off" cycles. It is rare when I have a short run cycle. There are a couple in the log below, but this time of year is a little difficult because we barely need heat.

May-06 12:41:23 PM	 	Circulator	Circulator Started
May-06 12:41:23 PM	 	Circulator	Circulator OFF Normal Cycle - 06:16:38.7350377
May-06 6:24:45 AM	 	Circulator	Circulator ON Normal Cycle - 00:24:30.4019609
May-06 6:24:45 AM	 	Circulator	Circulator Stopped
May-06 6:00:15 AM	 	Circulator	Circulator OFF Normal Cycle - 13:39:11.0523699
May-06 6:00:14 AM	 	Circulator	Circulator Started
May-05 4:21:04 PM	 	Circulator	Circulator ON Normal Cycle - 00:18:58.1060372
May-05 4:21:04 PM	 	Circulator	Circulator Stopped
May-05 4:02:06 PM	 	Circulator	Circulator OFF Short Cycle - 00:00:11.9400048
May-05 4:02:06 PM	 	Circulator	Circulator Started
May-05 4:01:54 PM	 	Circulator	Circulator ON Short Cycle - 00:01:36.4940261
May-05 4:01:54 PM	 	Circulator	Circulator Stopped
May-05 4:00:18 PM	 	Circulator	Circulator OFF Normal Cycle - 08:21:27.7424673
May-05 4:00:18 PM	 	Circulator	Circulator Started
May-05 7:38:50 AM	 	Circulator	Circulator Stopped
May-05 7:38:50 AM	 	Circulator	Circulator ON Normal Cycle - 00:16:29.6789122
May-05 7:22:20 AM	 	Circulator	Circulator Started
May-05 7:22:20 AM	 	Circulator	Circulator OFF Normal Cycle - 01:42:48.2535253
May-05 5:39:32 AM	 	Circulator	Circulator Stopped
May-05 5:39:32 AM	 	Circulator	Circulator ON Normal Cycle - 00:15:50.3063821
May-05 5:23:42 AM	 	Circulator	Circulator Started
May-05 5:23:42 AM	 	Circulator	Circulator OFF Short Cycle - 00:01:04.9382179
May-05 5:22:37 AM	 	Circulator	Circulator Stopped
May-05 5:22:37 AM	 	Circulator	Circulator ON Short Cycle - 00:03:04.9681948
May-05 5:19:32 AM	 	Circulator	Circulator Started
May-05 5:19:32 AM	 	Circulator	Circulator OFF Short Cycle - 00:00:02.7930044
May-05 5:19:29 AM	 	Circulator	Circulator Stopped
May-05 5:19:29 AM	 	Circulator	Circulator ON Normal Cycle - 00:05:57.5979401
May-05 5:13:31 AM	 	Circulator	Circulator Started
May-05 5:13:31 AM	 	Circulator	Circulator OFF Short Cycle - 00:00:02.7130004
May-05 5:13:29 AM	 	Circulator	Circulator Stopped
May-05 5:13:29 AM	 	Circulator	Circulator ON Normal Cycle - 00:11:57.9067248
May-05 5:01:31 AM	 	Circulator	Circulator Started
May-05 5:01:31 AM	 	Circulator	Circulator OFF Short Cycle - 00:00:02.4759994
May-05 5:01:29 AM	 	Circulator	Circulator ON Short Cycle - 00:01:13.2963152
May-05 5:01:28 AM	 	Circulator	Circulator Stopped
May-05 5:00:15 AM	 	Circulator	Circulator Started
May-05 5:00:15 AM	 	Circulator	Circulator OFF Short Cycle - 00:03:51.0686106
May-05 4:56:24 AM	 	Circulator	Circulator Stopped
May-05 4:56:24 AM	 	Circulator	Circulator ON Normal Cycle - 00:25:50.9819832
May-05 4:30:33 AM	 	Circulator	Circulator Started
May-05 4:30:33 AM	 	Circulator	Circulator OFF Normal Cycle - 00:06:20.1724801
May-05 4:24:13 AM	 	Circulator	Circulator Stopped
May-05 4:24:13 AM	 	Circulator	Circulator ON Normal Cycle - 00:23:42.1049540
May-05 4:00:31 AM	 	Circulator	Circulator OFF Short Cycle - 00:00:00
May-05 4:00:31 AM	 	Circulator	Circulator Started
May-05 4:00:31 AM	 	Circulator	Circulator OFF Normal Cycle - 11:38:46.8834006
May-04 4:21:44 PM	 	Circulator	Circulator ON Normal Cycle - 00:21:22.5723298
May-04 4:21:44 PM	 	Circulator	Circulator Stopped

The short Off cycles are not a problem, since it is only the circulator, the burner is controlled by my logic or the burner control module. While I sometimes override the built in logic on the burner by delaying it, it will normally cycle on when there is demand and the supply temperature is below 175 degrees and cycle off when it reaches 195 degrees.


I also extract as much heat out of the boiler as possible when heating hot water, but no heating zones. The burner is shut off about 8 degrees before DHW target, with the circulator continuing to run until the tank temperature is equal to or above the supply from the boiler.

Thermostats are usually designed with a 1 degree swing, though I have seen some that can be set to 2 degrees. The bi-metal strip with a mercury bulb usually has a 3-4 degree swing and have an adjustable heat anticipator - a nichrome wire heater in the thermostat housing. An Arduino "thermostat" could work the same as a conventional thermostat, where you set the swing and even heat anticipation based on your needs.

[nofreeze]

Awesome!

First off I want to say you guys are awesome! I did not see notifications of responses and when I logged in I found all of your responses and they are all very helpful so thank you!

I main reason that I am doing this is because the room that is a problem is a bonus room above our garage which is around 8-10 degrees hotter/colder than the rest of the upstairs. Living in Arizona that is uncomfortable to be in the room. The reason why I want to then "monitor" the room is because I dont want to cool the rest of the upstairs too much. We have spent alot of money redoing AC ducts and insulation to get where we are right now so there is not much else I can do besides use technology to try and cool the room when we are in it.

Thank you for the ideas of creating a virtual device.
The devices that I have in the room are the HSM200 Multi-sensor, 4 z wave dimmer switches a Z wave fan switch and a in wall Controller switch. I also have Harmony hub and I am adding the zwave extender today.

The Cycling of the AC system is a concern for me as that is not good to do. The reason why I am overshooting the cooling point is because the room heats up much faster than any other room in the house and I only want to keep that room at a comfortable temperature when we are in the room. I thought over shooting would help with the AC cycling too much. I am sure there is a better or more efficient way of doing it?

Any ideas on how to limit the AC from cycling too fast? I created a simple event as was in the first post and it worked ok but I could tell that it was cycling the AC faster then normal.
Thanks again for the help!

[Kerat]

Event Help to monitor a device

I recommend Tapatalk to monitor the forums from your phone. We have a really good forum environment that seems pretty well developed and helpful.

To protect against short runs you could create a new timer and tie it into the events.

Add an action to the event that is ran when the occupancy virtual device changes states to on and has an action that turns the cooling system on. The second action should restart the timer.

Do 2 things to the "off at 77 degrees cooling" (with a condition of occupancy is yes) event. The first should be a condition that states "and if the timer is at or greater than x minutes. The second thing is to add an action that stops the timer.

At this point your structure could theoretically miss turning off the cooling system if you got to 77 degrees before the timer was greater than x minute. We probably need to adjust the events to catch the cooling system and turn it off after x minutes.

Then create a second "cooling off event" that runs when the timer reaches y minutes (which would be the absolute maximum time you want the cooling system to run), with a condition that the virtual device is on. The event should turn off the cooling system and stops the timer.

Add an action to the "occupancy off" event that turns the cooling system off. The action should stop the timer.

The reason I recommended the occupancy virtual device was that you can create a few triggers by adding a few sequential "or if"s to the event that turns the virtual device to on or off. This allows you to tie a few detection methods together for better accuracy.

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[Uncle Michael]

I main reason that I am doing this is because the room that is a problem is a bonus room above our garage which is around 8-10 degrees hotter/colder than the rest of the upstairs. . . . The reason why I want to then "monitor" the room is because I dont want to cool the rest of the upstairs too much.

Have you considered a dedicated auxiliary unit for that room? That would allow you to focus the extra conditioning on just one room and avoid over cooling other rooms. If you sized it appropriately you could maximize its efficiency and short cycling could be designed out from the start. You'd definitely improve the comfort in the room, and you might even recover (at least some of) the extra cost from increased efficiency.