cat-doorbell

README

cat-doorbell

Receive a notification when the cat wants to come inside (Bluetooth Low Energy).

You'd think just keeping an ear out for meowing would work, but if the house is closed up and the cat is trying to enter through a different room, it's very easy to miss the sound. This project is a simple way to get a notification when the cat is at the door.

Build

Debian

sudo apt install libasound2-dev libgtk-3-dev libayatana-appindicator3-dev
go build

MacOS

brew install create-dmg
./build-darwin.sh

Usage

To receive a notification when the MAC address AA:BB:CC:DD:EE:FF is detected by the Bluetooth receiver, run the following command:

./cat-doorbell -a tcp://doorbell-receiver:1883 -u cat-doorbell -p mypassword -m AA:BB:CC:DD:EE:FF

Debian System Tray

To run the program in the system tray on Debian, you can use the following:

sudo apt install gnome-shell-extension-appindicator

Log out and back in, then enable the extension:

gnome-extensions enable ubuntu-appindicators@ubuntu.com

mkdir -p ~/.config/autostart
install -m 755 linux/CatDoorbell.desktop ~/.config/autostart

Bluetooth Receiver Setup

You'll need a machine to act as the Bluetooth receiver. I'm using an old intel NUC running Debian bookworm. The receiver will run a MQTT broker, and a client to listen for Bluetooth Low Energy device advertisements.

Prerequisites

• Docker

Tools

sudo apt install bluez mosquitto-clients

Configure Broker

mkdir -p config
cat > config/mosquitto.conf <<EOF
password_file /mosquitto/config/passwordfile
allow_anonymous false
listener 1883
EOF
docker run -it --rm -v $(pwd)/config:/mosquitto/config \
  eclipse-mosquitto:latest \
  mosquitto_passwd -c -b /mosquitto/config/passwordfile cat-doorbell mypassword

Run Broker

docker run -d --name mosquitto_broker -p 1883:1883 \
  -v $(pwd)/config:/mosquitto/config \
  eclipse-mosquitto:latest

Run Bluetooth Receiver

You can now listen for Bluetooth Low Energy devices and publish their MAC addresses to the broker.

sudo hcitool lescan --passive --duplicates | awk '{print $1}' | \
  mosquitto_pub -h localhost -p 1883 -u cat-doorbell -P mypassword -t "bluetooth/devices" -l