A doorbell and intercom solution running on Raspberry Pi.

Note: This project is not ready for production. It does run the doorbell in my house, but you should not expect to install this and get a ready-to-use solution without doing significant modifications.

Features

• Ringing the door from another instance or with a switch.
• Intercom system with audio and video streaming.
• Touchscreen interface.
• Access control using numeric keys and RFID tags.
• Using a PIR motion sensor for controlling the screen saver.

Hardware Requirements

Each instance needs a Raspberry Pi with the following accessories. The software was currently tested using the Raspberry Pi 3 B+ and Raspberry Pi 4. Other models might or might not work.

• Raspbian Buster (earlier versions don't work).
• Connection to a local network.
• An official Raspberry Pi 7" touchscreen.
• A USB webcam with a microphone.
• A speaker on the Raspberry Pi audio jack.
• A Raspberry Pi camera module for video streaming (optional). USB webcams might or might not work since they can be quite broken on the Raspberry Pi's USB port.
• An RC522 RFID scanner (optional).
• A PIR motion sensor (optional).
• A relay shield from Sequent Microsystems (optional).

Software Setup

Cross-Compilation

The build directory contains a Docker image and a CMake toolchain file with all necessary dependencies to cross-compile the project for a Raspberry Pi. To build a deb package, simply run

./build/build.sh

Installation

To install the project on a Raspberry Pi, first download and flash a recent Raspbian to it (Raspbian Buster is required). Connect the Raspberry Pi to a network and install the deb package to it.

For convenience, there are some scripts in the build directory to simplify deployment over SSH. To use them, you will need to enable SSH on the Raspberry Pi by executing

sudo systemctl enable ssh
sudo systemctl start ssh

Note that enabling SSH might be a security issue. You should at least change the password of the pi user. Deploy your SSH key to the device using

ssh-copy-id pi@<IP ADDRESS>

on the host. You can then build and install a deb package by calling a single script:

./build/install_remote.sh pi@<IP ADDRESS>

The project is installed as a systemd service. It is enabled by default and will automatically start after a restart. You can manually execute

sudo systemctl start/stop dingdong.service

to control the service. The settings can be edited in /opt/dingdong/settings/settings.json.

Dependencies

For build dependencies see the Dockerfile in the build directory. Building for x64 (for debugging purposes) requires the amd64 version of the same libraries whose armhf version gets installed in the Docker image.

Runtime dependencies are declared in the deb package. In addition to the libraries required at build time these are:

• gstreamer1.0-omx-rpi for hardware accelerated video encoding.
• gstreamer1.0-pulseaudio for using PulseAudio sinks and sources in gstreamer. As a gstreamer plugin, this is not a shared library dependency, but only loaded at runtime.
• pulseaudio is used for all audio functionality in the project. Launch scripts assume that they can control audio settings through pactl and with PulseAudio environment variables.
• sox for the play binary that is used to generate beep tones.
• wiringpi for the gpio binary.
• x11-xserver-utils for the xset command that is used to control the screensaver.

Hardware Setup

Touchscreen

Connect the Raspberry Pi touchscreen as described in https://www.element14.com/community/docs/DOC-78156.

Camera

If you want to use a Raspberry Pi camera module, connect it to the Pi and set the option videoDevice to the video device you want to use (e.g. /dev/video0). Instances which accept calls automatically will also start the video stream automatically when a call starts. Other instances will get a button in the call screen that allows to enable transmission of the video stream.

RFID Scanner

The application supports using an RC522 RFID scanner with 13,56MHz RFID tags for access control.

Connect it as described in https://github.com/ondryaso/pi-rc522. For a reference with images you can also see https://pimylifeup.com/raspberry-pi-rfid-rc522/, but don't forget the IRQ pin which is not connected there.

GPIO Actions

You can set up actions in the settings file. These can be executed after entering a key codes or scanning an RFID chip. For each action, add an entry to the actions object in the settings file.

"actions": {
    "key": {
      "caption": "Some Action",
      "pin": 1,
      "duration": 1000,
      "order": 1,
      "remote": false
    }
}

Actions can have the following properties:

• The key of the action must be a unique name and is used to reference the action in the settings.
• pin is the number of a GPIO pin that gets set to high when the action is executed. See https://pinout.xyz for the pin layout of the Raspberry Pi. We use the BCM numbers of the pins.
• duration is the duration (in milliseconds) the pin gets set to high.
• order is a number that controls the order in which actions get shown on screen.
• If remote is set to true, this action can be executed from another instance while it has an open call with the instance of the action. This can be used to e.g. open the front door remotely.

You can also use a relay board from Sequent Microsystems (documentation can be found here). At the moment just one of them is supported using the address 0 (no jumpers set). An action's pin number refers to an output of the relay board instead of a GPIO pin when you add a flag relay to the action definition and set it to true.

Ring Button

To allow ringing with a button (e.g. from your apartment door), connect a GPIO pin to ground through the button. Specify the pin and a ringtone for when the button gets pressed in the settings file.

Motion Sensor

The application can control the screen saver with a PIR motion sensor. Connect it to any pin as described in https://thepihut.com/blogs/raspberry-pi-tutorials/raspberry-pi-gpio-sensing-motion-detection and enter the pin number in the settings file.

License

Copyright (C) 2020-2021 Daniel Saier

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

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This repository includes some external dependencies, which are licensed under different terms. See the license and readme files in the subdirectories for more information.