Light Automation based on Head Counts

[billykwan88 0]

Hi everyone, I am still new here so please correct me if I am wrong. I was trying to search about light automation and there are still nothing mature in the market. This is what I found about how people do it now:

1.) Pairing PIR sensors with the light switch, as the sensors are infrared sensors, the lights may turn off while you are sitting still or lying on bed.

2.) Pairing door sensors with lights, this is not quite useful as I don't usually close my door.

3.)

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, this actually makes more sense but I prefer plug and play solutions.

So, I am thinking maybe we can think of a better way to do light automation with current tech based on headcount. If you have a better way, please share. If you are good at coding, please see if you would like to help.

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Here is an idea...

- Place one PIR sensor (PIR1) outside the room, and one PIR sensor (PIR2) inside the room, there will be an area that two sensors overlap and both can be on at the same time.

- Set up a counter (HEAD) to count the number of people in the room.

- Set up a variable (STEP) to see whether the person is entering or exiting the room.

- HEAD=0

- Loop for every second

- If PIR1=OFF and PIR2=OFF, then STEP=0

- If STEP=0 and PIR1=ON and PIR2=OFF, then STEP=1

- If STEP=0 and PIR1=OFF and PIR2=ON, then STEP=3

- If STEP=1 and PIR2=ON, then STEP=2 and HEAD=HEAD+1

- If STEP=2 and PIR1=OFF, then STEP=3

- If STEP=2 and PIR2=OFF, then STEP=1 and HEAD=HEAD-1

- If STEP=3 and PIR1=ON, then STEP=2

- If HEAD > 0, then LIGHT=ON, else LIGHT=OFF

- End Loop

Does anyone have comments on above setting?

Would it actually work?

Could you find any bugs in there?

Any expert would like to try to write a set of code that can be copied and pasted and used by everyone?

Any sharing would be appreciated!!

Thanks!!

[skoTner 0]

A good solution would be if there existed a thermographic network camera with a good API. Ask the API for objects within camera range that has a heat signature. Then you would know realtime if the room had living souls in it or not. But I guess the search for such a camera would be endless, and if one were to find a camera... the price would probably kill you.

[billykwan88 0]

Yes skoTner! I guess that might be quite expensive and some may find it insecure to have so many IP cameras across the house, including washrooms.

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[skoTner 0]

Yes skoTner! I guess that might be quite expensive and some may find it insecure to have so many IP cameras across the house, including washrooms.

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A hackers dream?

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[umbex 3]

Nice idea. It seems you are not really counting "heads" but "entrances": what if two heads enter exactly at the same time, and just one leave the room?

Or while one enters, another exits?

[billykwan88 0]

Thanks umbex! You are right! It gets complicated if there are more than one person. Adding below might help a bit

- If HEAD=0 and PIR2=ON, then HEAD=1

- If HEAD>0 and PIR2=OFF for maybe 30 mins, then HEAD=0

[Guest Kuuno]

my personal opinion is that it might be cool but probably is little "over automation"

most precise things would be cameras looking or some rfid/nfc counting probably like mentioned earlier?

[ivan.ruban 3]

Would it actually work?

Could you find any bugs in there?

It's diffucult to say since algorythm is quite complicated. It's best if you implement it and try. But it can be really tricky in situations that umbex mentioned:

what if two heads enter exactly at the same time, and just one leave the room? Or while one enters, another exits?

I personally don't have a solution for "light on presence" and reading this post with a high interest. Nevertheless I have one scene that I use in my bathroom - I use both door and motion sensors there to control lights. The light will never turn off if the door is closed and motion is detected inside. But this will work only for bathroom where people usually close the door, so not an option for other rooms. Code is available here if you are curious but it is not so good:

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Finally I think the easiest solution for "light on presence" problem will option 1 in your list:

1.) Pairing PIR sensors with the light switch, as the sensors are infrared sensors, the lights may turn off while you are sitting still or lying on bed.

To avoid turning off whlie your are lying on a bed, put a much bigger timeout (=30 min). Not so energy efficient but the comfort is more important!

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