Doorbell notification to phone

 Doorbells are useful in that they let you know when someone wants to come into your house or deliver a parcel.  But what if you are in the garden or away from home?  You can buy expensive doorbells with video and the ability to let you talk to the person at the door via your mobile phone or you can try to do something simpler on the cheap.

We had a bell push button linked to a 6 volt battery operated ding-dong chime.  I added a wire from the push button circuit, reduced the voltage to 3 volts, and connected this to a GPIO pin in the Raspberry pi model 4.  It could then sense when the voltage went on/off on a bell button push and, in theory, send a notification to my mobile phone.  It sort of worked but the notifications seldom came through so I guess I had something wrong in the code.

We were struggling to hear the ding-dong chime, partly due to increasing age and partly due to the cheap bell push button, which people never seemed to press in the middle so it would not operate.

In January 2023, I bought a Byron doorbell.  This has a small battery in the unit at the front door that transmits via radio 433 mHz frequency to two speakers.  One is mains powered and is plugged into a socket on the landing upstairs.  The other is battery powered and mobile.  It sits in the kitchen and could be taken into the garden e.g. if a delivery was expected.  The chime is plenty loud enough and the mobile speaker seems to solve 99% of the previous issues.

However, wouldn't it be nice if I got a notification to my mobile phone for when I am out.  I bought a cheap receiver (£2) and transmitter from eBay.  Plugged them into a pi model 3B, downloaded some python code and listened for the doorbell.  Nothing much.  I put the doorbell next to the receiver and it worked.  I had attached an antenna as per youtube but it still only had a range of a few feet or so.  My friend Julian lent me a 'better' one from RF Solutions (still only £4) and it worked perfectly!  I could now pick up signals from the doorbell when it was at the front door.

The install software needed is available from https://github.com/milaq/rpi-rf,  plus download the python 'receive' script.

When you press the doorbell, it sends a radio signal to the speakers.  It sends a code that is unique to your doorbell to avoid street confusion!  When I had noted the 2 numbers it used, I could adapt the 'receive' script to filter out unwanted signals (I am getting half a dozen on average every minute from random nearby equipment in the street).

I send the code to Home Assistant via MQTT.  I have set up a MQTT doorbell 'sensor' in the HA configuration.yaml file.  

- id: '1675931614708'

  alias: Bell rung

  description: 2nd doorbell

  trigger:

  - platform: numeric_state

    entity_id: sensor.doorbell

    above: 10

    below: 40000000000

  condition: []

  action:

  - service: notify.mobile_app_hry_lx1

    data:

      message: Bell rung

  mode: single

On my 'Overview' screen, on my PC and mobile phone, the code number is displayed (but reset to 0 after 5 seconds) and, through an 'automation', a notification is sent to my mobile.

All seems to be working but the filtering could be refined.

Updated to send info to a newer phone in Jan 2024.

System changed later in 2024 to a Byron doorbell, so no notifications are now being sent.