I have just set up a new Smarthings hub and sensor network and I am running into an odd issue. I have a button that I am using as a temperature sensor and light control in my shed. It works normally but goes offline at temperatures above 42 C. Is this expected behaviour or is there something wrong with the button? and if it is expected what is the max-min temperatures that the sensors can be used at?
Well above the operating temperature (40C)
I’m sure it is, but should it go offline like that?
Yes, if it overheats.
Well I agree that it is annoying!!! Some electronics do not do well with high heat.
I have an iris open close sensor that I am using for temperature monitoring and it goes offline almost every day in the middle of the day in the summer when the area it is monitoring gets above 100 or so.
This issue is most often the batteries, not the electronics. If you choose a mains powered device, you can usually get a broader temperature range. Just check the specifications before you buy.
However, you can’t just convert a battery operated device to mains power, as many have internal monitoring mechanisms that shutdown when the temperature gets out of range because they don’t know you now have mains power.
To @JDRoberts point, I do not know where the failure is from, battery or electronics, EXCEPT for this annecdotal evidence, in the past when I have looked into this, putting in fresh batteries usually did NOT help, BUT placing a NEW unit in that location seemed to fix the issue for some period of time, leading me to believe that there is some kind of “damage” that the heat does that happens over time, like there is a PC Board trace or something that becomes marginal and when the PC Board heats up, connection is no longer made. That the connection is normally fine at normal temperatures and might normally be okay at higher temperatures, but over time the PC board electric trace becomes more marginal works less reliable at higher temperatures.
I hope it is not the batteries, considering the button is less than a week old. I might change them anyways just to see if it helps though. I would have gone with mains power, but that isn’t an option in it’s current location.
Edit: Seems to still be online at 43C so far
To clarify, I am not saying that the batteries go immediately bad at that heat and I am definitely not saying that new batteries will help.
What I’m saying is that generally batteries are designed to operate in moderate temperatures and the rest of the device is designed around the idea that you will not exceed the specified operating temperatures.
Batteries can overheat, out gas, explode, or just be unreliable, any of which can then cause damage to the other parts since they were not designed to operate at those temperatures.
The device may be designed to shut down above certain temperatures to try to prevent damage from the battery overheating, but that’s a whole different issue.
Just find a device which is Spec’d to operate where you want to put it. That’s typically easier with mains powered devices, but there are some battery operated devices which can work in a broader range. They will usually be harder to find and cost more. As well as using more expensive batteries. But they do exist.
Just as one example, available in the UK, the Aeotec 4 button zwave key fob, which they expect people to keep in their cars, has a wider operating temperature, up to 50°C
It’s available on both the US and the UKZ wave frequencies, so make sure you get the frequency that exactly matches your hub.
I know that doesn’t have a temperature sensor, so it’s not exactly what you want, I just wanted to give you an example of a battery operated device with a wider operating range. If I think of one with the temperature sensor I will put it up.
There are other devices as well, that was just the first one that came to mind.