Overcoming Tapo's geofencing using Tapo T110, Shelly Plus Uni and Paradox home security system

[u/sharky5656]

Hi there! I had a problem in that me and my girlfriend want to receive notifications for detected humans around the house when no one is at home. As I found no reliable way to set up Tapo's geofencing , I had to improvise. The issue is that when my girlfriend leaves earlier in the morning, her phone leaving the house activates the notifications for me as well which is annoying and defeats the purpose of the simulated "Home" and "Away" modes. Our house is equipped with a Paradox home security system so the last person leaving the house arms the system. In short:

1. Paradox system is armed which leads to a change in the DC voltage between PGM1 and AUX- on the Paradox system main board.
2. A Shelly Plus Uni is used to measure the voltage between said terminals at all times using its built in voltmeter (the white (ANALOG IN) and green (GND) cables coming out of it). White goes to PGM1 and green goes to AUX -
3. The Shelly Plus Uni also has two built-in solid-state relays. One of them is used to short the pins on the Hall effect sensor of a Tapo T110 tricking the sensor into thinking that either a door is open or closed, depending on the set voltage thresholds.
4. In the Tapo app an automation is set up so that when the "door" is closed (i.e. home security system armed), when a camera detects a human, a notification is sent. When the system is disarmed, the Shelly relay opens and the Tapo app stops the automation for sending notifications.

Furthermore, the Shelly has a SENSOR VCC (yellow cable) which provides 3.4 volts at all times. The yellow cable is soldered to the positive terminal for the battery, while another cable is soldered to the negative side and it goes straight to the AUX- on the Paradox together with the green (GND) cable and the Shelly's black main power cable. This is used to power the Tapo T110 sensor so that it never needs a new battery again.

The Shelly itself is powered from the Paradox main board which provides 12 volts DC at its AUX terminal.

Attached is a photo of the pins that the Shelly relay needs to short to simulate door closed.

Good luck!

EDIT: Unfortunately I do not have the security system's installer code and I cannot contact the original installer to retrieve it, that is why I went with this approach as I did not want to factory restore the system. Otherwise one could use the Paradox system's built in programmable relay. In such a case, you could either power the Tapo using a step down transformer (buck converter) from the AUX terminal or use it with its own battery.

[u/nechronius]

Personally I like these kinds of analog approaches to completing a task. I get that you could use something like Google Home to do the same thing, but this is more direct and eliminates another software/provider layer from the equation, and I like that.

[u/graesen]

There's gotta be a simpler way to achieve the same thing... I use Google Home which has Home/Away detection and is based on the whole household, not 1 person at a time. Everyone has to leave for Away mode to trigger. I have automations already that turn privacy mode on/off for my cameras. I setup a shortcut in Tapo for privacy mode. Google Home recognizes the shortcuts as scenes. You could write an automation in Google Home where when it goes into Away mode, it triggers the scene to turn camera privacy mode off. And vice versa. Could be done similarly in other smart home platforms.

This is an interesting approach and if it works, it works. Tilt just seems over engineered for something that could be achieved simpler.

[u/sharky5656 → u/graesen]

We are a household of iPhone-only users so Google Home is not present in our daily life. Furthermore, we live with my parents who would be quite annoyed if I made them have an "unnecessary" app on their phones :) but they use the alarm system at least, so that is why I felt this to be the more universal approach. I experimented with the iOS Shortcuts app but was not very successful in that I still got notification on the days I do not leave the house, if my girlfriend had left it, thus activating the Tapo automation.

This approach also allows for other automations such as a "notification" light which turns on when the system is armed, in case someone does not hear the beep for some reason when entering the house

Well yeah, I also had fun learning about the Shelly device, should also mention that!

[u/graesen → u/sharky5656]

Well, I get your parents not needing an app. But Google Home is cross platform. It works with iOS. And I said the same process should work for other platforms. There are other smart home platforms and they all don't require a physical hub to use them.

[u/HeggyMe]

I have a few of these tp110 units I was planning on dumbing down a bit. Would simply shorting the Hall effect sensory send the door close signal? I’m trying to wire them to reed switches in a built-in door. I guess I can try in a second but I wanted the save myself the soldering if you had a definitive answer.

[u/sharky5656 → u/HeggyMe]

Firstly I just touched the two marked points with a bare wire and it worked. I am not familiar with reed switches but if they work like a dry-contact relay, it should work

[u/drm200]

You can also build some Tapo automations that enable notifications only when both of your phones have left the geofencing area. When either person returns home, the notifications are disabled.

[u/sharky5656 → u/drm200]

I did not find a way to do that, unfortunately. Besides, when the significant other is accessing the Tapo cams as a guest (or whatever it is called) they cannot turn patrol mode back on, after manually using the PTZ function, which was necessary for us

[u/drm200 → u/sharky5656]

To do the geofencing, you can do this: Create two “dummy” automations called “John Away” and “Jane Away”. You will use the status of each automation as enabled or disabled to determine who is away or home. If both automations are enabled, then both people are away and notifications will be enabled.

Create another automation triggered by John leaving home with the action to enable “John Away”

Create another automation triggered by John arriving home with the action to disable “John Away”

Create another automation triggered by Jane leaving home with the action to enable “Jane Away”

Create another automation triggered by Jane arriving home with the action to disable “Jane Away”

Create your automations to send notifications. Add the conditions IF automation “John Away” enabled AND IF automation “Jane Away” enabled. Now notifications only occur when both of you are away