Turning light on and off for a specific period of time?

I’m not finding this capability natively in the Smartthings app, is there another way?

Specifically I want to turn on a 120VAC outdoor strobe light for 2-3 seconds through this gizmo when the gate sensor is crossed. Basically “If sensor is opened, turn light on, wait 3 seconds, turn light off”.

This is a way to tell someone entering the property “hi, we know you are here” (opportunistic thief deterrent).

Similarly I want to turn on the strobe continuously when specific sensors remain open or closed, such as a burglar alarm or a smoke alarm then turn it off when the sensor returns to normal.

I looked into the iOS SmartRules app but it does not seem to offer that capability either though it seems basic to me, maybe I’m missing something?

The official smartthings features won’t schedule anything in intervals of less than one minute because with mesh, you can’t guarantee forced sequencing. Messages can and do bounce around the network in unpredictable ways.

That said, webcore will let you schedule down to the second, so you can just try it and see if it does what you want. I think that’s what most people use.

Separately, some Z wave devices and some zigbee lightbulbs do have this capability built into the device itself. So if you happen to have one of those you should be able to send one command that causes a blink.

For example, you can do this with hue bulbs connected to a hue bridge through their IFTTT channel.

You can also do this with Cooper Z wave switches if you have a smart app that can send the command.

So there are a couple of options, but Webcore is probably going to be the simplest. :sunglasses:

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BTW, If you are interested in it as a burglar deterrent Or safety alert, the fortrezz siren has a strobe option which is popular and works well with smartthings. It’s much more likely to get attention then just a regular bulb blinking on and off. It’s officially supported, but there’s a community device type handler with more options.

@krlaframboise Should know if there are other security devices that can also strobe, he has written several device handlers for these. :sunglasses:

Thanks, I’m familiar with this one but it’s an indoor device, I was planning on installing a powerful waterproof strobe light, it will be exposed to rain.

thanks. Been reading about webcore here and there, sounds like I need to get more familiar with it.

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more webcore info for you…



If this does not work, the work around I’m thinking about is to use a programmable relay.
Some relays can be programmed to toggle on/off once triggered but then I would need to use 1 relay for each scenario of lighting which is not ideal and can get costly.

If it’s an outdoor light and you are in the US, check with your local township as many prohibit strobe lights that would be visible from a neighbor’s or from the public street under their “nuisance light” or “light pollution” or “light trespass” laws. This is true even if they are part of the security system. And if they are part of the security system, they are typically limited to no more than five minutes of operation at one time.

So it’s just something you need to research.

If it is legal in your area, I would look for a device which does the blinking or Strobe on its own, and then all you would need to do is turn the power on.

As far as a burglar deterrent, most police departments recommend just having a normal bright light come on and stay on, not blinking, as burglars do not want to be seen attempting to enter the home. Strobes are more often used as warning signals to people living in the home.

FWIW :sunglasses:

Thanks for the tip, I’ll check with the town indeed.

I already have flood lights, some on movement sensor some on dusk/dawn automation, this would strictly be used for entry warning and in case of alarm.

I was planning on indeed using an actual strobe light that does the blinking on itself. Powering it on is easy, what I was not finding is how to power it off after a short time laps of about 3 seconds or so for the entry warning purpose.

For the alarm purpose it is easier as I can turn it on when the sensor is open and turn it off when the sensor is closed.

If I turn a light on using a smart plug, is there a way to time it to off?

For example I set a custom SHM rule to turn it on if the smoke alarm is triggered. However there is no time setting so it stays on until I turn it off manually.

Sure. :sunglasses:

Assuming you don’t want to use Webcore, then this would be a classic case for a virtual timer.

Rather than turning on the plug directly, you would turn on a virtual device which has a countdown timer using the “power allowance” feature. And you would set up a separate smart lights automation to have the real device follow the countdown timer. Then when the countdown timer goes off, the real device will turn off also, but you will still be able to use the real device in any other automation without triggering the countdown.

There’s a how to article for this in the community – created wiki:


It’s often used for porch lights, where people want to have the porch light turn on when they get home and automatically turn itself off after five minutes – – but they also want to be able to turn it on from the switch without having it turn off again on its own.


Thanks. It’s really disappointing that such a basic thing is not natively available though.

Then I’m afraid you’re in for a great deal of disappointment. SmartThings is a very flexible, powerful platform, but the official features are indeed quite limited. If what you want is a full-featured official rules engine, you aren’t going to find it here. :disappointed_relieved: There isn’t even an official way to group dimmers together.

At the same time, a great deal of the platform is exposed for custom code, and the community is both helpful and generous with time and solutions. So it just depends on what you’re looking for.


Agree what makes it good (and keeps it alive) is the community and open source. For what I am doing with it so far it’s working for me but its native limitations and lack of reliability are surprising considering a multi billion dollars company owns it. On the other hand I hope they keep it open.


All of the strobe related devices I’m aware of can only be used indoors.

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I’m using an automotive strobe light actually, it is weatherproof but of course it is not directly connected, thus the smart switch. I’ve found a workaround using the siren that is much better, just more expensive see this post

Apparently the link is broken, could you please update it?

The link is fine, the host for the wiki is having problems today. :disappointed_relieved: Hopefully it will be fixed soon.