Finding your lost smartphone with Home Assistant

Your smartphone keeps hiding in from you? Every time you want to leave it is missing? Fear not, my Home Assistant smarthome helped me solve that problem and here is how I did it.

Losing your smartphone

Today (nearly) everyone carries a smartphone most of the time, me and my girlfriend included. Now at home you might put it on a table, sofa, bed or somewhere else and before you know it… ups it is gone. Now imagine you want to leave or need your phone for any other reason: the search begins. The last time this happened in my apartment I thought there must be a smarter solution then running through every room searching manually.

If you use multiple modern Apple or Android devices you might be able to use “findmy” or similar services to do this but that requires some second device to trigger the search. That device itself might be playing hide and seek at the same time… But why do all of that if we already have a perfectly functional smart home setup with apps on all devices?

Integrating your smartphone with Home Assistant

The first step to finding your phone is to integrate it with Home Assistant. Doing that is fortunately quite easy: just install the free official app (Android for example) on your device. That works for iOS, Android and even smart watches.

The app allows you to easily control your devices from the phone but it also (if enabled via settings – companian app – sensor management) expose a bunch of sensors to Home Assistant representing the status of your phone.

I use this sensor data for example to slowly dim up my lights in the morning to wake me up without an alarm sounds. Very useful and probably a future blog post here. Now the important part is that it also allows you to send notifications to the phone.

Letting your phone ring

The easiest way to find your phone – if you know it is somewhat close by – is to let it ring. Fortunately the notifications you can send via Home Assistant do support sounds and can even break through the do not disturb mode if set to the highest priority.

The official documentation for the companion app describes the whole process quite well here. It includes examples for iOS and Android. There is a second page here with more information on selecting sounds.

The automation

I decided to start with a simple automation. I have a smart wireless button (Aqara, set up via ZHA) next to my door that already triggers some automations:

• a single click turns off all lights when I want to leave
• a double click starts my robot vacuum (migrated to Home Assistant now)

It is time to add a third one now. On a long press I want the phone to start playing a sound so it can be easily found. In this case I am looking to trigger this alarm for my girlfriends iPhone.

alias: Find phone alarm
description: "Triggers an alarm on the phone if the button next to the door is long pressed"
triggers:
  - trigger: event
    event_type: zha_event
    event_data:
      device_ieee: 00:15:8d:...
      unique_id: 00:15:...
      command: hold
conditions: []
actions:
  - action: notify.mobile_app_name_iphone
    metadata: {}
    data:
      message: I am here!!!
      title: Phone looking for you!
      data:
        push:
          sound:
            name: default
            critical: 1
            volume: 1.0
mode: single

The trigger uses the events published published by ZHA (my setup, coordinator) to listen to a long click (“hold” command). There are currently no conditions but for example a check if the phone is connected to the local network could be added.

If you want to support the blog consider buying your hardware via the affiliate link below:
Sonoff Zigbee 3.0 dongle plus (great and cheap but might not be powerful enough for bigger networks)
TubesZB coordinator (expensive but very powerful)
Pixel watch
Roborock vacuum (I use an older S50)

The action then sends a high priority notification to the phone. This always rings (ones), even during do not disturb mode and makes it easy to find the phone. The important part is in the data block: critical makes the notification important enough to show right now and the volume: 1.0 sets the volume to 100% so it is easily heard.

This works quite well although I will spend some more time on this later trying to create a longer alarm, maybe with a custom sound and to get the same behavior on Android (where my phone was not playing any sound with the notification so far).

So far the automation has been simple to set up and quite the success, already allowing us to find the phone(s) a couple of times.