Smart Cities - Phone for Seniors with Vision Impairment

Building a simple telphone for seniors with vision impairment

Building a simple telephone for seniors with vision impairments using a Raspberry Pi can be an enriching and functional project. Below are the steps to create a device that allows seniors to call loved ones, leveraging either the internet (e.g., VoIP) or interfacing with a traditional mobile phone. The design emphasizes ease of use, accessibility, and practicality.

Project Overview

Features: Large, Accessible Buttons: Physical buttons for calling predefined contacts. Tactile feedback for easy navigation. Voice Assistance: Text-to-Speech (TTS) for confirmation of actions. Simple voice commands to perform tasks. Internet Calling: Using VoIP services like SIP (Session Initiation Protocol). Mobile Phone Interface (Optional): Interfacing with a traditional mobile phone via Bluetooth. Speaker and Microphone: High-quality audio input/output for calls. Materials Required Raspberry Pi (Model 3, 4, or Zero 2 W recommended for performance). MicroSD card with Raspberry Pi OS installed. USB speaker or 3.5mm-compatible speaker. USB microphone or headset with a mic. Large tactile buttons or a numeric keypad. Breadboard and jumper wires (for prototyping buttons). A touchscreen or an e-ink display (optional for feedback). USB or Bluetooth module (for mobile interfacing, optional). Power supply for the Raspberry Pi. Step 1: Setting Up the Raspberry Pi Install the OS: Install Raspberry Pi OS on the MicroSD card using the Raspberry Pi Imager. Enable SSH, Wi-Fi, and audio support. Update and Upgrade: Run the following commands: sudo apt update sudo apt upgrade Install Required Libraries: Install libraries for GPIO, audio processing, and VoIP: sudo apt install python3-pip pyaudio alsa-utils libportaudio2 pip3 install gpiozero pyttsx3 Step 2: Adding Physical Buttons Connect Buttons to GPIO: Connect large tactile buttons to GPIO pins on the Raspberry Pi using jumper wires and a breadboard. Each button corresponds to a contact. Write a Button Script: Create a Python script to detect button presses and initiate calls: from gpiozero import Button from subprocess import call import pyttsx3

1. Define buttons and actions

button1 = Button(17) # GPIO pin 17 button2 = Button(27) # GPIO pin 27 engine = pyttsx3.init()

def call_contact(contact_name):

   engine.say(f"Calling {contact_name}")
   engine.runAndWait()
   call(["linphonec", "-c", contact_name])  # Replace with actual VoIP command

button1.when_pressed = lambda: call_contact("Alice") button2.when_pressed = lambda: call_contact("Bob")

print("System ready. Press buttons to make calls.") while True:

   pass

Run the Script: Save the script (e.g., call_buttons.py) and execute it: python3 call_buttons.py Step 3: Setting Up VoIP (Internet Calling) Install a SIP Client: Install a lightweight VoIP client such as Linphone: sudo apt install linphone-cli Configure SIP Account: Sign up for a VoIP service provider (e.g., Linphone, Asterisk, or Twilio) and configure the SIP client. Test Calls: Test internet calls using the command line: linphonec > call sip:example@domain.com Step 4: Mobile Phone Interface (Optional) Bluetooth Pairing: Install Bluetooth tools: sudo apt install bluetooth bluez Pair the Raspberry Pi with the mobile phone: bluetoothctl Use Bluetooth Protocols: Use protocols like HFP (Hands-Free Profile) to route calls through the Raspberry Pi: Install and configure ofono and pulseaudio. Test Call Routing: Verify audio routing from the mobile phone to the Raspberry Pi. Step 5: Accessibility Features Text-to-Speech Feedback: Add TTS for actions like confirming button presses and errors: engine.say("Call in progress.") engine.runAndWait() Voice Commands (Optional): Install voice recognition libraries like SpeechRecognition: pip3 install SpeechRecognition Step 6: Enclosure Design Build a Custom Case: Use a 3D-printed or handmade case to house the Raspberry Pi, buttons, speaker, and microphone. Label buttons with Braille or large text for accessibility. Add Power Backup: Include a portable battery pack for uninterrupted usage. Step 7: Deployment and Testing Predefine Contacts: Configure contact details in the script or VoIP client. Test Audio Quality: Test speaker and microphone placement for optimal clarity. Stress-Test for Usability: Simulate real-world use with seniors to refine the interface.