Raspberry Pi Doorbell Application

This application plays a sound through the Raspberry Pi 3.5mm headphone jack. This is a nodejs application.

This application uses a Raspberry Pi connected to two Battery Operated Wireless Door Chimes (https://www.bunnings.com.au/hpm-battery-operated-wireless-door-chime_p4061828). The circuitry for the chimes has been removed from the plastic housing and connected to Raspberry Pi GPIO ports.

The sound that is played is the file found in config/sounds/default.mp3. This application assumes that the mplayer application is installed on the Raspberry Pi.

This application allows you to set up notifications to be sent via services to alert you of a doorbell press. The services that are currently set up to receive a trigger are:

• Facebook Messages (https://developers.facebook.com/docs/messenger-platform/send-messages/)
• Pushbullet (https://docs.pushbullet.com/)
• SMS Gateway Me (https://smsgateway.me/sms-api-documentation/getting-started)

The parameters for these services are configured in config/default.json and bin/start_door_bell.sh files.

Prerequisites

• Hardware

  • This uses modified HPM doorbell chimes and buttons connected to Raspberry Pi GPIO ports. Specifically the HPM D642/05 model has been used but you can use a similar one. (See also the Instruction Manual). Each doorbell was modified by replacing the speaker with a 47 ohm resistor. The GPIO was then connected to one side of this resistor to await a trigger of the doorbell button being pressed.

  See the attached circuit diagram:

  For doorbell modifications, see

  For Raspberry Pi connections see

• Software Dependencies

  • This is a nodejs application. In order to install this application you need to install npm.
    • See https://docs.npmjs.com/downloading-and-installing-node-js-and-npm for more details.
  • mplayer application
    • See below instructions under Getting Started for installing mplayer.

Getting Started

1. Connect the Raspberry Pi GPIO port one or two Doorbell chimes. Update the config/default.json parameters (doorbell_pin_1 and doorbell_pin_2) with the appropriate port numbers. Note that these will be the GPIO port numbers and not the physical pins from the head. See https://pinout.xyz/pinout/wiringpi#.

2. Install mplayer application. Ensure that the mplayer application is installed. If it is not then use the following commands to install:

   sudo update
   sudo apt-get install mplayer
   

   To test, ensure you have connected a speaker to the headphone jack and run the following commands:

   cd <directory_where_application_is_cloned>/config/sounds
   mplayer default.mp3 
   

3. Install the node modules. Use the following commands to download and install the modules:

   cd <directory_where_application_is_cloned>
   npm install
   

4. Create a symlink from /home/pi/bin/start_door_bell.sh to <directory_where_application_is_cloned>/bin/start_door_bell.sh:

   • for example if you have cloned the application into the directory, /home/pi/my_pi_doorbell, then use the following command to create a symlink:

     ln -s /home/pi/my_pi_doorbell/bin/start_door_bell.sh /home/pi/bin/start_door_bell.sh
     

   Test that the startup script is working by running the following command:

   /home/pi/bin/start_door_bell.sh
   

   Try each of the doorbell buttons to confirm that you hear a sound.

Congratulations! You have installed the application successfully! To have the application start automatically when you start the Raspberry Pi, follow the instructions for doorbell.service under the Pi Doorbell bin directory heading below.

Application and Service Configuration

The config/default.json file is used to configure parameters for both the doorbell set up connected to the Raspberry Pi and the services that you wish to use when a doorbell press is performed.

• Doorbell parameters:
  • doorbell_pin_1 : sets the GPIO pin of the first doorbell
  • doorbell_pin_2 : sets the GPIO pin of the second doorbell
• Service parameters:
  • Parameters for the services that you wish to use are defined under the services parameter in the config/default.json file.
  • enabled : Each service can be enabled using this parameter by setting it as true or false.
  • params : This is service specific parameters. These are detailed in comments for each Service in the config/default.json file.

Pi Doorbell bin directory

This directory contains the following files:

• start_door_bell.sh

  • This file is a bash script to start the application.
  • This holds the API Key information, as environment variables, for the services:
    • Facebook Messages (https://developers.facebook.com/docs/messenger-platform/send-messages/)
    • Pushbullet (https://docs.pushbullet.com/)
      • Currently only Notes are sent using Pushbullet.
    • SMS Gateway Me (https://smsgateway.me/sms-api-documentation/getting-started)
  • The following environment variables are used:
    • Facebook Messages
      • FB_PAGE_ACCESS_TOKEN : Access Token for Facebook Messages API
      • FB_RECEIVER_ID : Receiver ID for Facebook Messages API
    • Pushbullet (https://docs.pushbullet.com/)
      • PB_API_KEY : Pushbullet API Access Token (https://docs.pushbullet.com/#api-quick-start)
    • SMS Gateway Me (https://smsgateway.me/sms-api-documentation/getting-started)
      • SMSG_PASS : Smsgateway password for your account
      • NOTE that at the time of writing this Android app was removed from Google Play
  • If you do not wish to use these services then you can leave these environment variables commented out.

• doorbell.service

  • This file is used as a Raspberry Pi systemd service to start the application at boot time

  • This file assumes that the startup file (start_door_bell.sh) is in the directory /home/pi/bin/start_door_bell.sh

  • In order for this to take place you need to copy this file to /etc/systemd/system as root user.

  • Ensure that the access permissions are set to -rw-r--r--

    • You can use the command sudo chmod 644 /etc/systemd/system/doorbell.service.

  • You can also run the commands to stop, start and review the status of the application:

    • Stop the service:
      • sudo systemctl stop doorbell
    • Start the service:
      • sudo systemctl start doorbell
    • Show Status of the service:
      • sudo systemctl status -l doorbell

• www

  • This starts the application http server.
  • This is currently only as a default Express server.