Automating Kitchen Ceiling fan

[sirmeili]

So, I've installed a ceiling fan in our kitchen (a small 34"). I would like to automate it, but the room itself offers some unique (to the house) differences to other rooms.

So for other rooms, I automate the ceiling fans (Where I can) based on occupancy. The problem with the kitchen is that it's a pass through room, so people often pass through staying very little in the actual room. This is ok for lights where you want them on even if you are passing though, but it's a waste to turn on the ceiling fan just for someone to pass through and to have it on for any length of time. Also since the kitchen can contain very little movement while in the room, the occupancy timeout is higher than in other rooms.

Current State:
Right now I have it set so that if the room is occupied for 10 minutes, then it turns the ceiling fan on - seems to work ok, but having that number lower might be better (still testing it)
If the room is unoccupied for 15 minutes, turn it off (this accounts for leaving the room while cooking and coming back in). - This has the issue that if it's 13 minutes unoccupied and someone walks through the room, you start over!

I do think the 15 minutes is too long as the past few days it seems that the fan never turns off.

potential "enhancement"
I was thinking I could have some kind of timer system in place. for instance, only turn on the fan if it has been occupied for X of the last Y minutes (8 of the last 10 minutes), but only count time where the occupancy of the room is "Occupied" for more than 1 minute (The timeout of the sensors). I think I could do this with timers, but I haven't looked too heavily into it.

I was thinking the same for unoccupied. If it was unoccupied for say 8 of the last 10 minutes and it's currently unoccupied, then turn the fan off (maybe add that it's currently unoccupied for a set amount of time, like 1-2 minutes).

My biggest issue is keeping a "rolling" count. with a timer I would have to reset it after some kind of "timeout", which might not be optimal. Optimally I would be able to say "give me the amount of time this device was active in the last 10 minutes from "now". I'm wondering if this should/could be a plugin as I can't think of a way to accomplish this at all.

Any thoughts or am I just being silly and I should have the fan turn on with the lights?

[Uncle Michael]

Another option to consider is a counter. Run an event periodically, say every 15-30 seconds. If motion is detected in that period, increment a counter. In another event, if no motion was detected in the last nn seconds (where nn can be longer than the period for the increment event), decrement the counter if it is greater than zero.

When the counter is greater than a set value and the fan is off, turn the fan on. If the value is smaller than a (different) set value (to allow for hysteresis), turn the fan off if it is on.

To limit the time required for no motion to turn the fan off, you can set an upper limit for the counter. That will prevent the counter from increasing to astronomical values when the kitchen is continuously occupied for an extended period of time.

[Black Cat]

You did say kitchen, I wonder if you have a electric stove? If you have then you could use a current sensing device to indicate the status of the stove/hotplate to determine your occupancy?

[sirmeili]

You did say kitchen, I wonder if you have a electric stove? If you have then you could use a current sensing device to indicate the status of the stove/hotplate to determine your occupancy?

I did, and I currently do, but...

Being in the kitchen doesn't always mean the stove is used. We often us an electric griddle to cook for the fam. We are also getting ready to convert to gas. I would like to at some point monitor the power usage at the box, but we just aren't there yet.

I do have an extra aeotec power monitor so maybe I'll monitor the stove anyways for now until we switch. I'm a fan of having multiple ways to detect occupancy. The more the better

Sent from my XT1585 using Tapatalk

[Rvtravlr]

We use HSM200's in our open concept kitchen. They are set to 1 minute for motion reporting.

With a timer, luminence and temperature, we control Lights on, off and fan on and off.

With the fan, the trigger is temperature and the condition is occupied (when motion is detected a virtual device, Kitchen Zone, becomes true). When the zone becomes unoccupied, or false, the Lights and fan are turned off.

My rationale for the fan is that it circulates air which helps in our open concept design and the extra electricity used when the timer is counting up even though there may be no motion is negligible. I'd rather the ceiling fans rotate the air and make the living space comfortable rather than have the A/C come on.

Event 1:

If Kitchen HSM200 temperature is set and is > 73
And if Kitchen Ceiling Fan is off
And if Kitchen Zone is Occupied
Then control device Kitchen Ceiling Fan to 20%

Event 2:

If Kitchen HSM200 is set to motion
Then control device and set Virtual Kitchen Zone to True
Restart timer Kitchen

Event 3:

If timer Kitchen becomes > 30 minutes
Then control device set Kitchen Lights to off
Then control device set Kitchen Ceiling Fan to off
Stop timer Kitchen
Set timer Kitchen to 0
Set device Virtual Kitchen Zone to False

Hopefully Randy, rprade, will chime in because there may be a more efficient logic; that is what makes HS3 so powerful, there are many ways to achieve the final result.

Michael

[randy]

Michael's events would work fine.

I will share my approach to determining if a room is occupied vs someone just passing through. Unfortunately it only works with very fast response PIRs. I use DSC hardwired PIRs that are virtually instant, with no motion timeout. These sensors will toggle to motion and continue switching between no motion and motion as long as there is motion within their range. This gives me the ability to determine occupancy with a counter and timer. I use this method in a number of rooms. The concept is to increment a counter and resume a timer with each motion. Another event will reset the timer and counter when the timer reaches XXm, XXs. You can then trigger an occupancy event off of the counter. For example our bathroom fans will turn on after the counter exceeds 5, the counter and timer are reset after 2 minutes. The end result is the fan will turn on if there is constant motion (6 indications of motion within a 2 minute period), but will not if we just visit the medicine cabinet. The fan and lights are turned off after the PIR has been No Motion for 30 minutes. The fan is turned off 10 minutes after the light is turned off as long as there has not been motion in the interim.

In the kitchen you could stack conditions and triggers to look at the stove being on, motion recently, lights on, etc. We don't use the stove to detect kitchen occupancy since there are many occasions where something is simmering with no one in there. The kitchen lights use the same motion timer and counter as above, only to turn them off when the room has been vacant for a specific period.