Triggering Alexa tone/notification using NO/NC relay or 12v DC output from RE-4K Plus Receiver (driveway alert system)

Ok, I am a newbie with all this smartthings stuff. I searched for hours but couldn’t find a solution I could understand. So I am hoping that I can get some assistance and possibly add some useful content for anyone looking for a similar solution. I did see some topics about using a 12v DC output from an alarm panel and hooking that up with either a stepdown converter or a relay to a Z-wave door or water sensor and using that to trigger events. But that was about as detailed as those threads got and that was from a few years ago so I thought I would post this again and see if there were any known 12v DC triggers out on the market yet.

Here is the situation. Our driveway is on the side of our house and there is only one window facing it. If we are not in the breakfast room then we don’t get to see the driveway. We want to know when we get visitors whether it is a delivery driver that doesn’t bother walking around to the front door or a guest. So I found the metal detecting Dual 4k Plus driveway alert system. This kit comes with 1 DAPT-4000 and one RE-4k Plus receiver. The receiver puts out a tone when the sensor detects a vehicle. However, we have a large house and a large outbuilding. I could get several of the receivers and put them all around the property but at $60-$75 each that would add up fast. The receiver also has two NO/NC relays and a 12VDC output terminal. So I thought why not use the Alexa devices to send a notification/doorbell tone to all the dots and echos we already have spread around. Unfortunately, the receiver is not a smart device. So I am looking for some way to use one of the relays or 12v DC output to send a doorbell type tone to our Alexa devices.

So I know how to solder and can do some circuit hacks/bending if needed. I just need to follow a plan to do it. I am also not quite sure how to use a water sensor to send a tone to all the Alexa devices. I searched Amazon for water sensors that work with Alexa and didn’t see any sensors in the results.

Does anyone know of a device or somewhat simple solution that can be used?
Can you walk me through the basics of how to do it?

If I understand what you’re asking for, assuming that you also have SmartThings (this forum is for people who are using the Samsung SmartThings ™ home automation platform), this is easy. :sunglasses:

  1. Connect the driveway sensor to any open/close sensor that works with SmartThings.

See the following FAQ for some typical devices of this type. (The topic title is a clickable link.)

These devices will then show as “open “ to SmartThings when the relay is activated. And smartthings will pass that information along to Alexa.

  1. when that sensor shows as open, use that as the
    “When this happens” in an Alexa routine (not a SmartThings routine)

You can have the action in that routine be having any or all of your Alexa devices make a specific announcement. Or you can have them play from a set of available sounds, including several different chimes. You create this routine in the Alexa app.

So it should be very straightforward.

If by chance you aren’t using the Samsung SmartThings system, you would need to find any standalone Wi-Fi open/close sensor that works with Alexa that can act as a dry contact and you should get the same result. I just don’t happen to know specifications for those since, again, the assumption is that all of the questions and answers in this particular forum are for people using Samsung SmartThings.

Alexa routines can be triggered at the present time from an open/close sensor, a motion sensor, or a lock. So that’s what you need as the trigger.

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Than you for the reply. Yes, I have the Samsung Smartthings Mesh WiFi hub system.

I also just found this video showing how to hack a door sensor:

So I am thinking I can do this with the door sensor but instead of hooking the wires up to the contact panel as shown in the video I could just hook the wires up to the NC contacts on the RE-4k Plus receiver. I should be able to directly connect the wires to the relay contacts, correct? Then when the receiver gets the signal from the driveway sensor it will open the relay contacts and the door sensor will read that as open and then I can set up the push notification from that, correct?

The physics are different in that. The water sensor isn’t carrying a charge.

Just buy a device which is designed for this purpose, that is, which already has dry contact points in it. It will be way easier and safer.

Also, Wyze sensors don’t work with smartthings. So, as always, the first rule of home automation applies: the model number matters.

Check the community FAQ for the list of devices that are already designed to accept external input and you should be good to go. They will have internal screw terminals, so you don’t have to solder anything or take the device apart the way the guy did in the video. You just open the case, and attach the wires.

Btw, it’s hard to beat the zooz zen17 for this purpose as long as you’re on the North American frequency.

Right, you couldn’t hook it up to the 12v DC output but the built in relay shouldn’t put a load on that circuit. That is what a relay is for, right? I was using the video as an example not necessarily saying to use the Wyze contact sensor but any contact sensor should work pretty much the same, physically speaking.

So you could do the same thing with this Samsung Smartthings contact sensor:

The Zooz Z-Wave Plus Universal Relay would work. I could just connect the 12v output to the Zooz relay. It says it needs a custom device handler to work with Smartthings. How hard is it to set that up?

Use an EcoLink Z-wave tilt sensor. It has a set of contacts that can be connected to the NC/NO contacts in the the driveway controller. It shows up in ST as a contact sensor, so it can also trigger Alexa Routines. And it is less than $12.


Wow, the EcoLink Z-wave tilt sensor looks like exactly what I need and it is so affordable. I will give it a try and report back. The driveway sensor will be coming in soon. Thanks.

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When I ordered the TILT-ZWAVE2-ECO a few months ago it was only $9 and the sent me the more recent version TILT-ZWAVE2.5-ECO.

Also it pairs with the new stock Z-Wave Sensor Edge Driver, so it will continue working with the new ST architecture

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This is the tutorial I followed. I have notifications sent to my phone via SmartThings, and Alexa announcing “someone is here”.

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Just thought I would post an update. I got the EcoLink Z-wave tilt sensor and added it to Smartthings. Used the Alexa Smartthings skill and then Alexa recognized the sensor so I just setup an Alexa routine. In order to get the EcoLink Z-wave tilt sensor dry contacts to work in any position I had to cut one lead on the tilt sensor attached to the circuit board. That is the cylinder shaped object which sounds like it has a ball bearing rolling back and forth. Connected some wire leads to the dry contacts and now when I cross the wire the sensor shows closed and when they are not touching it shows open.

I setup the Alexa routine to make an announcement when the sensor shows closed. I tested the sensor by crossing the wire leads and the Alexa routine works. I then hooked up the wire leads to the RE-4kplus relay terminals. One wire to the Com terminal and the other wire to the NO terminal.

I tested the driveway alert and it is not triggering the Alexa routine. I extended the contact time on the relay to 5 seconds and still not working. The RE-4k Plus receiver goes off but the relay is not triggering the Alexa routine. I will do some more testing on it later… maybe try the other relay (there are two on the RE-4k Plus. If it still is not working then I guess I will have to call Dakota Alert about the receiver. I have double checked and from what I can see I am using the correct terminals and all dip switches are setup correctly on the RE-4k Plus.

Well, I set the RE-4k Plus for a 15 second relay trigger and I just got a notification from Alexa when it went off. I will do some more testing on it later. I am not sure if that is what made the difference… When I crossed the wires I only had to touch them for a second. Anyway, it appears to be working properly now. I will post another update later.

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I still need to do some more testing on the Alexa announcement. I also set a routine in ST to send me a text for now so I can see if there is a breakdown in the communications and where it might be happening (IE between the tilt switch and the ST hub or in the Alexa routine.

I looked a few times in the ST app to see how I can set up a ST routine to make Alexa do an announcement but I don’t see an option to push anything to Alexa in the ST app. The only options I see are “Notify Someone” and Change this location’s mode".

I am just starting out to setup a smart home system so I don’t have any other devices to control or scenes setup so that is why those options are greyed out. When I clink on the Notify Someone option I only see “Send notification to members” and “Send text message” Play message on speaker is greyed out.

I will try to do some more research on ST and Alexa integration. I can see in the settings that Alexa is integrated but I don’t seem to have any options to do anything with Alexa in the ST app.

The SmartThings /Alexa integration is at present one way. Smartthings will expose its devices to Alexa so that you can use voice control with them or, if they are a contact sensor, motion sensor or a lock, you can use them as the trigger for an Alexa routine (not a SmartThings routine).

Alexa devices do not show up in the smartthings app and you cannot issue commands to them from smartthings.

However, the good news is that an Alexa routine CAN have an echo device as the target, so you can create custom voice notifications there.

The question then is how do you put these two things together?. That is, have an event on the smartthings side trigger an announcement on the Alexa side.

This is a very popular use case, and it’s pretty easy, although you do have to do some setup work.

What you will do is use the Alexa routine to make the announcements. Then you will use a smartthings sensor (either real or virtual) to trigger that routine.

And specifically, if you want to use a virtual device, it’s usually best to use a virtual device which is BOTH a switch and a sensor, so that when you turn the switch on, the sensor looks like it opened. And when you turn the switch off, the sensor looks like it closed. That way you can turn the virtual device on and off by voice or with a smart things automation and the sensor piece will trigger an Alexa routine.

I’m surprised you haven’t found this in your research, as there is a community FAQ on it and it is a very popular use case.

Here’s the direct link to that FAQ. It also provides the information you need to create that special kind of virtual device.

FAQ: Can I trigger an Echo Action without Speaking to It?

In the future, you will probably save yourself a lot of research time if you start with the quick browse lists in the community-created wiki and look in the project reports section. For example, there are lists there for alerts and for voice projects: either would take you to this information. :sunglasses:

How to Quick Browse the Community-Created SmartApps Forum Section - Things That Are Smart Wiki

You might also want to take a quick look at the FAQ section of this forum, as many common use cases are discussed there. But the quick browse lists are probably quicker because they are more specific.

I did not know about the wiki page. I will check that out.

For this case, I did not need verbal control over the sensor. I can see how that would be useful in some situations so that you for the recommendation of a switch/sensor combo.

I have read some information about Alexa integration but didn’t see anyone specifically state that it was one-way or that Alexa could not be added to ST routines. In fact, I read some statements that seemed to indicate otherwise. So I thought I was missing something. Thank you for explaining it to me.

So here is my current situation… I have reliably been getting the text messages from the ST routine. Everytime we have a visitor the contact sensor is triggered and I get a text. The Alexa routine seems to be the problem. Either there is an issue with the Alexa Skill communicating with ST or a problem with the Alexa routine itself. My echo device has only made an announcement a few times. I would say it has been about 20% effective.

I am not sure where to go from here or what I can do to fix the issue between Alexa and ST.

Also, I was a little disappointed to see that I could only specify one echo device on the routine. So I would need to create separate Alexa routines for each echo device I want the announcement to occur on.

You can have multiple devices or all devices. You do it as an announcement.

Can you post a screenshot of your Alexa routine that isn’t working?

Back in 2017 or 2018 there were a couple of smartapps that could go the other direction but they turned out to be too resource intensive and smartthings shut them off. Two popular ones were echo speaks and Alexa assistant. So if you found very old posts, that could be the confusion.

Oh, I see. I had it setup with “Alexa Says” instead of announcement. I just changed that.

Here are a couple images to show what the routine looked like before and what it looks like now.

It seems when I change a device setting I have to select the device that the setting will be changed on. So I can’t have her increase the volume of the statement but maybe the announcements are at full volume by default?

Well, my Alexa routine is still not working. I am reliably getting the text message from ST so the sensor setup and the ST routine is working fine. I haven’t had this kind of trouble with my other Alexa routines so I am guessing that there is some kind of breakdown in communication in the ST Alexa Skill.

I am probably just going to end up getting another Receiver from Dakota Alert for the other building. Unfortunately they are not loud enough that you can hear it everywhere in the house. I might eventually use the 12v relay with another chime device and put that somewhere else in the house. I was really hoping to use the Echo devices we already have. At least there is one good thing about connecting the ST sensor to the DA receiver… now I have a record of every time a vehicle pulls in our driveway. If I ever need to I can use that to cross reference our security camera feeds.

Have you tried having the Alexa routine do something else like turn on a light? Just to see if it’s the ST integration or the routine details.

Also, if you post a screenshot of the new Alexa routine and of the details page from the ST app for the trigger device, that might help.

Are you seeing the virtual sensor open and close in the ST App? Just as an example, the ST routine might be able to trigger from a virtual switch but the Alexa routine ignores switches (any switches, virtual or physical) and requires a sensor device as a trigger.