LIghtwaveRF & Pseudo State / Multisensor -- would this work?

(Daniel) #1

Hi All,

I’ve read many of the posts about the limited lightwaverf integration that exists. I had this perhaps wacky Idea but wanted to get peoples thoughts on this…

I have around 50 hue light bulbs in my house and also some inline relay switches behind some of none hue lights e.g. for outside lights etc. This is all turning in to a rather expensive hobby!

I have some less used areas of the house that I’d stil like to automate the lighting of, mainly motion sensing, but also be able to turn on/off based on routines etc.

LightwaveRF in the UK is so much cheaper, I realize there are imitations though including it being stateless.

So take a small ensure bathroom.
Two light switches outside the bathroom
I want lights to turn on when I walk in (at night only)
I want my away routines to turn off the lights
Ideally I’d want to know if the lights are on or off at any given time

So, I install a lightwaveRF switch to control the two lights (very cheap)
Buy a smart things compatible multi sensor and mount this on the ceiling right next to one of the light bulbs
If the light level picked up by the multi sensor are > X then the light must be on and so turn a virtual switch (bathroom lights on)
If the light level drops below < X then the lights must be off and so turn the virtual switch off

If the virtual switch is toggled through smart things to on, then turn the lightwaveRF switch on and vice versa

Use the multi sensor to detect motion as well and turn the lights, on/off accordingly.

Would this work? I’d know if lights are on and off via the light levels - maintaining pseudo state leverage lightwaverf for the low cost control over the switches.

What are peoples thoughts on the practicalities of this? Could it work?



Just looked at from an if A then B sequence, it should work. Assuming of course that you have something set up that allows you to tell lightwave RF to come on after a SmartThings action.

Whether it’s practical or not, though, depends very much on your specific situation, and in particular the amount of lag.

Most customer satisfaction studies have found that people expect a light triggered by motion sensor to come on in under half a second. Closer to 300 ms is usually preferable. Any longer than that, and people perceive themselves as moving into darkness.

I would doubt very much if the set up as you describe can achieve that target timing. But you would have to test it to find out.

My own tendency would be to get a lightwave RF motion sensor to provide motion activation of the lights, and to use the SmartThings integration for the other aspects of the use case you’ve described.

The next question is which lux sensor to get. These vary quite a bit in sensitivity, and some of them only report every 15 minutes. That’s probably not going to match your requirements here . But you just need to read the specs carefully before purchase. Do be aware that the more often you have the sensor checking the environment, the faster the batteries will run down.

The easiest case will be the one where you want to turn the lights off when you leave the home, because then lag won’t matter very much.

So while it’s doable to have a SmartThings-controlled motion sensor turn on a virtual switch which then triggers turning on the lightwave RF switches, i’m just concerned about whether the delay will be too long to be acceptable.

(Daniel) #3

Thanks for the reply on this - food for thought…