A few quick questions

(Doug ) #1

Hey guys. had a few questions i was hoping someone might have a answer too.

  1. Is there a water temp sensor? I’m looking to make shower temp auto adjusting.
  2. Can i use the smartthings presence sensor with 2 hubs?
  3. What fires the mobile presence sensor? I noticed it is usually off but if i have the smartthings presence sensor in my pocket then the mobile presence will fire as soon as the smartthings presence does.
  4. Im curious about the wireless in wall light switch, How does it work? I am assuming that you can control the switch with a mobile device but what am i controlling? The power to bulb? or am i telling the switch to turn on and its turning on a group of devices that are associated with it? or both?
    Hopefully that makes since. Basically what i want to do is have a switch control my GE Link wireless bulbs via wireless. i want the power from the switch to the lights to stay active and powered on at all times.

(Nick D) #2

Here’s what I can throw in:

Need to ask someone else but I was eyeing this guy: Water and Temperature Sensor, Wireless, Z-Wave https://www.amazon.com/dp/B007TAWKWK/ref=cm_sw_r_awd_UirVub1VD63HY .

The 2 hubs thing is odd. 1 hub is for one location. (House, beach house, etc). You would be defining your home as 2 separate homes, thus splitting the houses zwave network. If rand is an issue, the way zwave works is its a mesh network. Each device takes a signal and passes it on. So for me, my hub is near my zwave thermostat, which is near my living room lights (zwave) which is near my harmony hub, which is near my zwave garage opener and tilt sensor. In other words, the zwave signal carried the hub signal to the garage door and tilt sensor and everything in between. (+ vice versa).

The presence sensor, I’m not an expert on. But I know that it a small zwave device that, when it gets in range of your zwave network, it can trigger something.

If you have GE connected bulbs, buy a smartthings hub and link the bulbs directly to smartthings. No need for a switch. Just find a way for always on power. (Connect cable to cable, etc.) To control the lights you could use your phone or buy a minimote/Jey fob and keep in in said room.

Hope it helps!

(Doug ) #3

I do have a hub, I was going to buy a secound one for my grandparents and just wanted to know if i could use my presence sensor on that hub too or if i would need two(One for my house and one for theirs)

I was asking about the light switch becuase there are times when my wife will use the switch to turn on a light then she turns it off. This creates a issue. I would like a switch that works as a switch but does not actually cut the power to my smart bulb.
Hopefully that makes since. We have a 1yr old and our schedule can change at anytime(Get up at 3am to put him back to bed) while holding him i dont want to have to pull my phone out and launch a app to turn on a light when im already walking past a switch…

(Brice; SmartRulesApp.com) #4

I think if you want to be able to use the switch, then you’re better off putting “dumb” bulbs back in the lights, and instead replacing the switch with a Z-wave switch (http://www.amazon.com/Z-Wave-Wireless-Lighting-Control-Switch/dp/B0035YRCR2/ref=sr_1_1?ie=UTF8&qid=1421679467&sr=8-1&keywords=z-wave+switch+ge). Then you get the ability to control it via the switch or the app, and the app works even when the switch is turned off.

(Gary D) #5

It depends on the switch. Typically, both the physical toggle on the switch, and the z-wave radio are controlling a relay inside the switch. The relay is closing or opening the circuit between the “hot/line” and “load” wires attached to the switch.

(I think) There are some switches that support associations, in which case the relay can also trigger other z-wave devices to do something.

Using a typical z-wave wall switch is NOT a good idea for the GE Link bulbs, as they’ll typically cut power to the bulb.


I believe the SmartThings presence sensor is a zigbee device, not zwave. The SmartThings hub can handle both zigbee and zwave protocols.

The ST presence sensor registers as “on” as soon as it is within range of the ST hub, typically about 50 feet. (The store description says “35 to 50 feet” but sometimes it’s a little further. It can get thrown off by all the usual things that can block zigbee signals.

The only reason you’d want to know that it’s zigbee, not Zwave, is if you want to put a repeater device in your garage or a street-facing room so you get a little further range. The most typical repeater people seem to use is the ST old motion detector, which can act as a zigbee repeater.

The mobile presence phone detection works using the GPS in your phone. Normally that triggers somewhat further away than the ST device, around 500 feet. However, geolocation services for cellphones are using range as well and your hub might get sent the location of the cell tower that found you (I don’t know if that’s always how that works), so you yourself could be in a slightly different location, a block or two nearer or farther.

If both your ST PRESENCE DETECTOR and your mobile phone are being detected by the hub at the exact same moment, it’s likely a coincidence based on some local geography that blocks or strengthens signals. (“Geography” in this case including houses, mail boxes, etc.)

If you set up a similar setup at your grandparents’ house, it’s quite possible the ST device would cover a smaller area than the cellphone detection.

So the ST presence detector is detected when a zigbee signal is successfully completed between your ST hub and the device. Typical range is 50 feet. A zigbee repeater can be used to extend this range another 50 feet or so if needed.

The mobile phone is detected when geolocation services tell your ST hub it’s in range. Typically around 500 feet, but varies, I believe depending on exactly which cell tower pings your phone.


Did a little more research. Apple devices handle geofencing through the operating system, and will often use the WIFi SSID if it is available, which is a little more accurate than the GPS and supposedly has less impact on battery life.

Anyway, if both cellphone and ST presence sensor are being detected at the same time, it could be because the phone is detecting your WiFi network then.

So again, it could work differently at your grandparents’ house, with the phone having a wider range.

(Doug ) #8

Thats how i was thinking it worked but i wanted to make sure. I love the automation i get but would like some physical control. Maybe i just need a “Button” on the wall that controls the “Lights” Via the smartthings hub. I do love the GE Link bulbs!

(Doug ) #9

I guess i could bypass the switch so power is always at the bulb. When you hit the physical switch button (Toggle) the lights does it also send out a signal?

In case that does not make since>> If the switch is in the on position and you flip it off. Will the smartthings hub know you turned it off?

(Gary D) #10

If you bypass the switch, how will the switch be powered? There are a couple of different ways to do it, but you’ll need to ensure that the switch has power. Once that’s done, most switches will send an ‘on’ command (even if they are already on) and an “off” command (even if they are already off.) So, it’s possible…

(Doug ) #11

I would just Tee the connection. Which would give me 3 connections
1st connection - Hot wire
2nd Switch
3rd to the light.

If the switch does a on/off command then this would work great. Ill stop by the store on the way home and grab a light switch and give this a try

(Brice; SmartRulesApp.com) #12

Yes, you can replace the switch with the z-wave switch and just not connect the load wire (the one going to the switch). Then, just connect the load directly in so it is always powered. In SmartThings, then you would add a SmartApp (something like The Big Switch) that subscribes to that switch and turns your GE Link bulbs.